Fixing a Realistic TRF radio's scratchy volume control the easy way

Realistic TRF 655 AM long distance portable radio, as it was when I bought it a few years ago at a thrift store -- this is before I fixed the volume control.

The Radio Shack, Realistic TRF is a well-known Long Distance AM band radio (known among radio nuts as a "DX radio") which was made in the 1970's. Some can still be found at garage sales, online, or at thrift stores -- where I got mine a few years ago.

A COOL THRIFT STORE FIND

I got my Realistic TRF 12-655 at a thrift store. The person who had it before must have been a painter, or had done some painting, as there are a few tiny specks of white paint on the case.

No sooner than I put batteries in the radio I found it worked great. The only glitches were two points on the dial where it will pop slightly if I tune across them very fast (common to older transistor radios with plastic mesh tuner capacitors), and -- well -- the reason I've written this article: the Volume Control was noisy.


This problem is one that is common to older radios, and especially common to older radios with slider potentiometers: scratchiness from use and internal wear in the slider.

In fact, the volume control on mine was so scratchy it was difficult to use with headphones, sometimes painful. It would pop. I found myself not ever using the radio.

The tone slider, however, was clean as a whistle.

SOME BACKGROUND ON THE TWO REALISTIC TRF MODELS

Before I go into how I fixed my volume control, I'll write a little bit about the TRF itself, because there are still radio distance-listeners out there who have these radios, and there isn't a ton of information out there about them.

The TRF came out in two different models, the 12-655 and 12-656 (there was an earlier variant in the 1960's apparently, I know very little about that one).

The 12-655 is the more well-known of the two, and many believe it is the better performer. Both radios have your standard RF amp - Converter - IF amp - IF amp - Detector - AF section radio circuitry. The main difference is that the 655 has a ceramic filter in front of the first and second IF amps, and the 656 has an extra IF can in between them instead.

Realistic TRF model 12-656, with slightly different styling, slightly different circuitry, and a tone switch.

A Realistic TRF 656 with its back off. This is the TRF model that came out after the one in the top picture. The shorter antenna and slightly different components can be seen. This is not the radio that needed the tone and volume switches re-wired -- photo just put in here for comparison.

The AF section in the 656 is a chip, the 655 has four discrete transistors.

The antenna in the 656 is shorter than the one in the 655 (as can be seen in the above photo). The 656 has a tone switch, and the 655 has a tone slider. The 655 has 'narrower skirts' in the selectivity, the 656 has wider skirts. That means, basically, that with the 656 you get a little more treble in your listening, but in the 655 you can tune to a weak station that is right next to a strong station, and hear it better.

The 655 seems to have an overall edge in performance, much of it due to the larger antenna and the selectivity may give it a slight edge as well.

The Realistic TRF 655 with the back off (after I fixed it). The loopstick antenna is about 180mm long or so, and fairly thick -- which pulls in signals quite well. You can see the yellow coded IF can with ceramic filter in the middle of the radio's PCB. It's a large metal 'can', which has the IF coil and ceramic filter all in the same enclosure.

IT WAS AN EASY FIX, ACTUALLY

Just before last winter's lousy Long Distance / DX season, I decided to fix the problem with my TRF's Volume Control. Not having any spare slider potentiometers handy, I did the next best thing: I swapped the wiring between the two sliders (tone slider and volume slider). That way the clean tone slider would be used for the volume, while the scratchier volume slider would be used for the tone, which I used less, anyway.

It wasn't that difficult to do -- in fact, it only took about 15-20 minutes, including disassembly, re-assembly, double checking to make sure I wasn't messing up the wiring, etc.

This is how the TRF's two slider controls, tone and volume, looked before swapping the wiring. The way the radio is wired at the factory, the tone slider is on the left hand side of this picture, the volume slider is on the right hand side in this picture. After being  re-wired, the new volume slider will be on the left side of this picture, and the new tone slider will be on the right.

The wiring swap is very simple: you just remove the wiring from the volume control and apply it to the tone control, and vice versa... and you must move the green capacitor in the picture above to a different pair of terminals. You don't have to know radio circuitry to do this fix.

WHEN REWIRED, THE CONTROLS ARE REVERSED

Now that the controls are reversed, and they also work in reverse: Full volume is when the slider as at the bottom of the radio, not the top. Full treble is when the tone slider is at the bottom, not the top. It's not that difficult to remember. The easiest way to remember is to make sure and shove the controls all the way back to the top when you're done listening to the radio.

(You could also swap the actual controls themselves, which would allow for them to work exactly in the same direction they did before fixing the problem -- but that would take a lot more work than just swapping the wires and remembering that the controls and direction you slide them is reversed).

The Realistic TRF's tone and volume controls with the wiring swapped. Now the old tone slider is the new volume slider, and the old volume slider is the new tone slider. Note the new position of the green capacitor -- it was on the top of the two controls, now it is on the bottom. Full bass and low volume are now when the sliders are all the way to the top. You now push them downwards to get more treble, and more volume.

So, if you do this fix the way I've shown it here, as soon as you're done -- push both knobs to the top. The tone will be on full bass (muffled), and the volume will be all the way down.


Otherwise, as soon as you turn on your TRF, it will be at full blast. You don't want that.


The Volume control will now be on the far right side (actually, a more convenient place for it, especially if you're right handed), and the Tone control will be on the inside, nearer to the speaker (also more convenient, as most people use the volume more than the tone control on these radios).

The original tone slider on these radios is linear taper, and the original volume one is audio taper. With the wiring swapped, that isn't all that much of a problem. You just have to use finer increments in setting the volume than before, that's all. It's not a problem for me at all. There still is enough play in the Volume control to make it very usable

With the wiring swapped, the new tone slider on mine works fine (with no noise) and so does the new volume control. 

WAITING FOR THE NEW LONG DISTANCE AM/MW SEASON

Last Long Distance ('DX') listening season was a stiff, of course. Consequently, I haven't DX'ed the AM band probably in nine months now. But I will haul my TRF out of the closet this October or so, plug in the headphones, and give the band a listen, and see if there is anything worth listening to.

The Realistic TRF is a very capable radio. I've heard Radio Rebelde from Cuba, about 2770 miles away, on just the internal antenna of my 12-655 (the radio pictured below) more than once. It works great with an external loop, too (also shown in the picture below).

A recent picture of my Realistic TRF as it is now. The volume control is now on the right side, and when the control is all the way up, the sound is all the way down. Where I have the volume set in this picture is where I usually have it. It's plenty loud. The tone control is now on the left, and where I have it set in the picture is a nice mix of treble. The circular thing to the left of the TRF is a Select-A-Tenna, a loop antenna that boosts signals to the radio. The dial in the middle of the Select-A-Tenna 'tunes' it to the radio. You just set the Select-A-Tenna next to the radio, turn the dial until the signal peaks, and you can hear AM radio stations on Mars! :-)

THE TRF's SOUND

Through the speaker these radios sound -- well -- like medium sized transistor radios. They have volume, especially the 12-655 model. But tone wise, they are a little bit thin. OK for talk radio, though.

But through headphones you get a much richer sound. The best way to Distance listen ("DX") with a TRF is using headphones. It's the best way to get the most out of these remarkable old radios.

A pic of me a couple years ago, a bit heavier and with a beard. The camera I used in this pic was a $20 digital snapshot camera.

Hope everyone is having a good October. Here it's 60+ degrees almost daily, and decent weather. The big-leaf maple trees here are getting orange leaves. Hopefully it will hold until the end of the month. I have been taking photos of them -- will put them up in a post soon. Thanks for reading!

CC 10-18-2014

Da Kommer Høsten -- Then Comes The Fall

Leaves from Oregon big-leaf maple trees. Big-leaf maples can turn pretty colors in the Fall, but usually are not as pretty as their Eastern maple cousins.

Summer lasted a bit longer than usual here in the Seattle area this year. Then came Fall.

Fall sometimes is my favorite season. Often it rains here in the Fall too much, and usually the weather starts to turn colder, which isn't fun when one remembers the warm summer temperatures.

The leaves here will turn yellow and orange during a good Fall but sometimes here in Sea Town they fall from the trees too quickly due to rain.

But my birthday is in October, and so is one of my favorite holidays: Halloween. So Fall always has a magic quality to it.

Halloween season always means the stores have lots of pumpkins out front, for carving into jack o' lanterns, table decorations, and making pies.

This is the time of year I guess my Irish ancestry begins to take over, as Halloween is a Celtic holiday. In fact, it was the Celtic New Year. When Christianity took over the Celtic countries, the Catholic Church created two separate Christian holidays that more-or-less covered the Celtic New Year: All Saints Day (November 1st) and All Soul's Day (November 2nd). Some of the ancient customs from the Celtic holiday made their way into All Soul's Eve festivities (caroling for 'soul cakes', for example, slightly resembled modern trick or treating), and All Saint's Eve became Halloween.

My grandfather grew up in rural Northern Wisconsin, in farm and forest country. When he was young, the trick or treating on Halloween was more trick oriented. One time my grandfather and his friends took apart a farmer's wagon, and re-assembled it on the roof of the farmer's barn.

Anyway, this time of year I pull out my Celtic Fairy and Ghost story books, and read some folklore. William Butler Yeats produced a terrific book for anyone who may be interested in Irish fairy folklore. It's called "Fairy and Folk Tales Of the Irish Peasantry", and is available online at various prices (including free, as the book has apparently passed into public domain). It has numerous fairy folklore stories collected by Yeats, many of them written by him, and a handful of excellent fairy folklore poems written by Yeats and other Irish poets.

I usually re-read the Yeats fairy book this time of year.

I also tidy up the place, and get the decorations out for Halloween, and start preparing for the other holidays.

One of the last photos I took with my Fuji AX655 snapshot camera, which locked up a day or so after this photo was taken. This photo was taken in the morning -- later in the day it was a 70 degrees out.

But this time of year I also begin to miss the sun. But it will be around again in about five to six months. 

The last photo I took with my Fuji AX655 before it locked up, on September 26th. It apparently doesn't like to be turned on or off with very weak batteries. The lens locked up so tight it would take a vise-grip to move it, and of course, that would break the camera. Now it is an SD card reader. :-) Other brands of cameras seem to have firmware to prevent this locking-up from happening -- hopefully. :-)

A lone maple tree lights up the otherwise green surroundings like a column of fire. Taken with my new Nikon Coolpix L32, which -- once you start using the 'Scene' button (which has all the light settings for the camera, and is very useful) -- is a great camera. So far.

Autumn leaves and some yellow and orange foliage along the Cedar River Trail earlier this week. Taken with my new Nikon Coolpix L32 snapshot camera, on its "Dusk/Dawn" setting.

Fall foliage around the Cedar River Trestle Frog Pond. When I first got this camera, I was unable to get good clear shots. Then I discovered the 'Scene' button, where the light settings are. This photo came out much better than I expected. Taken with the Nikon on "Dusk/Dawn" setting.

Soloppgang, October 6th, 2015. Taken with my Nikon L32.

One thing about Fall here in the NW is we often get nice sunrises. It must have something to do with the Fall cloud formations (i.e., more rain clouds in the sky). I was able to capture a couple of them with my new Nikon snapshot camera.

Soloppgang, Oct. 9th, 2015. Taken with the Nikon L32.

Aside from riding my bike, taking photos, and working, I have been still writing, and working out. Finally starting to reach the weight that I was pushing (bench presses) when I had to take a short break from it and start over again with better form. So I feel much better about that. It feels good to finally reach the point where I was in June, weight-wise.

I still have a few posts I promised about a month ago that I have to finish up and post here. I will probably dribble them out over the remainder of the year. There are quite a few pictures of Seattle I took over the Summer, some of which were really nice. It's just a matter of loading them up and making a post from them....

 A shot of the Cedar River Trestle in the morning sun in early October. Taken with my Nikon Coolpix L32 snapshot camera.

A wooly-bear caterpillar crosses the Cedar River Trail next to a small cottonwood leaf. Like with our local big-leaf maple trees, during most Autumns our cottonwoods generally turn yellow and then hit the ground. :-( Taken with my Canon A520 snapshot camera.

Harbinger of Fall: One of the last night softball games of the Summer season. I caught this game on the evening of October 9th. Softball is fun to watch because nearly every hitter seems to hit the ball into the outfield.

I hope that those of you who are reading this are having a good Autumn (at least those in the Northern Hemisphere), and may your trees have many Fall colors. For those who celebrate Halloween, have a fun, safe one.

CC -- Oct. 15th, 2015.

Fixing the SANGEAN PR-D5's low headphone volume

The Sangean PR-D5 is a very good AM-FM Stereo radio.

It looks like a mini-boombox, and is fairly loud through its high quality 2.5 inch speakers.

The Sangean PR-D5, an excellent Long Distance AM and FM stereo portable, with an AUX IN jack so you can listen to online, streamed radio stations and music also.

The PR-D5 radio is easy to use. It has five memories on AM and five memories on FM, which are easy to program: you just hold a memory button for about a second and it stores the station. It has a clock, and has an AUX IN jack (on the left side of the radio) which makes it even more useful.

There is a mono / stereo switch for FM, if needed for clarity (sometimes FM stations from the next metro come in clearer in mono than stereo, where you sometimes hear more flutter). FM, naturally, is stereo through the speakers and through the stereo headphone jack on the left side of the radio. Through its speakers FM stereo sounds great. Just like a small boombox.

The PR-D5 also receives RDS on FM, which works fairly well (RDS is a data service on FM -- the radio's LCD readout will scroll a station's call letters, ID, or a song title while you're listening to the station).

It will tune the AM broadcast band (known as Medium Wave, Mellombølge or Mellanvåg in parts of Europe) in 10 khz (the Americas) or 9 khz steps (Europe and the rest of the world), and it is easy to re-program the khz step if needed. The radio comes with a noise-free AC adapter.

A set of good heavy duty batteries (6 C Cells) can last a couple weeks or more in the PR-D5, and will last a bit longer than that if you use headphones.

I got my PR-D5 late last year because I kept reading about it being a good Long Distance AM radio, and I wanted to see how it worked with Long Distance AM band listening. I was also interested because it seemed to resemble a small boombox -- which in a sense, it actually is.

And I have a thing for boomboxes.

Naturally, the PR-D5 has stereo FM through its two speakers, and I figured I could run my tablet into the AUX IN and use it to play music and online radio that way.

Just like a boombox!

As soon as I got into my car after buying the radio I took it out of the box and put the batteries in, and fired it up. I switched to the AM broadcast band and immediately heard 1500 KSTP, which is a fairly long haul -- Minneapolis and St. Paul, Minnesota are over a thousand miles from Seattle (about 1400 air miles). And here I was, hearing ESPN from Minnesota in my car. I was very impressed.

TWO PR-D5 VERSIONS

The PR-D5 has had two variants so far: the older version of the PR-D5 apparently had a standard analog IF chip and PLL tuning. In fact, on the front of my PR-D5 it says "PLL Synthesized Receiver". The PR-D5 was apparently re-designed with a SiLabs DSP IF chip some time in late 2012 (according to the schematic they kindly sent me). So, technically, my PR-D5 is a "PR-D5B" (as it says on the schematic).

The newer version of the PR-D5, which I have, has a SiLabs digital IF chip (Si4731), and the AF power chip (UTC2025 / UTC20205) is possibly a different one, also. The digital chip may or may not be an improvement. The SiLabs digital radio chips can 'tune' the radio automatically to the antenna and receiving conditions, which makes the radio very sensitive to signals. The SiLabs series of radio chips have low noise amplifiers, digital to analog converters, and then the tuning, filtering, and amplification of the radio signals are done through a software program inside the chip.

The newer PR-D5 version also has the main PCB installed in the radio differently from the first production runs, and also has twin coils on the 200 mm loopstick antenna, where the older version just had one coil (twin coils can sometimes add to the sensitivity of an AM radio, make it pull in more stations).

A COUPLE SMALL DRAWBACKS...

As impressed as I am with the PR-D5, it has two drawbacks, one minor, and one not so minor -- if you are a Long Distance AM band enthusiast.

The first drawback is ironically also one of the PR-D5's AM band strengths: the 4 khz selectivity, which is great for Long Distance listening, but which also cuts down on some of the high frequency audio response.

(To non-radio nuts, 'selectivity' -- or 'bandwidth' -- is the capability of a radio to separate two stations which are very close to each other. If a radio has wide 'selectivity', a strong local station can overpower a much weaker station right next to it -- like a station in a distant city. With a radio with wide bandwidth, the local station will drown out the weaker station right next to it. With a radio that has narrow bandwidth -- like the PR-D5 -- the weaker, more distant station will more easily be heard.)

This radio has probably the best, narrow selectivity of any AM Long Distance portable I own.

The Sangean PR-D5 AM-FM portable radio with the back off, showing the 200 mm twin coil loopstick antenna (the long grey cylinder at the top of the green PCB board). The large size loopstick antenna pulls in lots and lots of AM band radio signals. The two coils of wire wrapped around the loopstick antenna help boost signals also. Most AM radios have just one coil on the loopstick antenna.

USE A GOOD SET OF FLAT-RESPONSE HEADPHONES

However, the excellent 4 kilohertz selectivity on the AM band gives the PR-D5 a midrangy, and slightly boomy sound, especially through some headphones. The narrow 4 Khz bandwidth cuts some of the treble on the AM band.


Some PR-D5 owners have complained about this.

Through the speakers, the sound is OK -- but through headphones (and many DXers, like myself, use headphones) the boominess of the PR-D5's audio can cover some of the highs. This is why you want to choose the correct set of headphones.

I've found that you can compensate somewhat for the the midrange and boominess (from the radio's apparent loudness circuit), by using a set of headphones with very flat audio characteristics. Headphones made for extra bass just won't sound great on AM plugged in to a PR-D5.

I have a set of Sony headphones (that came with my Sony SRF-59 headset radio) that sound great on all my radios except the PR-D5. When plugged in to the PR-D5, they add to the bass, and it makes IDing stations with the PR-D5 a challenge. They make the PR-D5 sound muddy.

So, with my PR-D5, I use a another set of older Radio Shack headphones (I don't remember the model number) that have a flatter response -- they have really good clarity, but they don't emphasise the bass like some headphones do. When I use the Radio Shack headphones, the PR-D5 doesn't sound muddy, and the highs come through better.

When I use those headphones, I find it much easier to DX with the PR-D5 on the AM band.

I have used cheap headphones from dollar stores that sound good with the PR-D5 also. The ones I got have a very flat response. Some cheaper headsets can have very flat audio response, and can sound really good with this radio.

SLOWER AGC THAN MANY OTHER RADIOS

One feature that may or may not be a 'drawback' is the PR-D5's slower AGC. AGC is the ability of the radio to keep the volume at a relatively constant level: when a signal drops in strength, AGC will boost it a bit to keep it from dropping out. Most portable MW and SW radios have fairly "tight" or "hot" AGC, some of them have AGC that is so tight it pumps. Not so with the PR-D5. The AGC on this radio is more natural, but sometimes when a signal fades you will definitely hear a momentary volume drop before it comes back up to full (this applies to newer PR-D5's with the SiLabs DSP chip. The older models with analog chips may not have AGC this slow).

It seems to be part of the design of the DSP section of the SiLabs IF chip -- possibly because the SiLabs chip 'sees' background static as 'noise', which it is attempting to 'silence'. However, the PR-D5 has no soft muting -- where the audio drops substantially when the signal drops a bit, almost sounding like the signal is disappearing -- which can be an annoyance to a MW DXer. Fortunately, there are no such extreme signal dropouts on low signals with the PR-D5.

The slower than usual AGC may be a contributor to the PR-D5's tendency to allow pulse noise through more than other radios. Pulse noise, like AC hash, shows up a bit more on a PR-D5 than some other radios, like the Sony ICF-38 for example, which softens it a bit.

LOW HEADPHONE VOLUME ON NEARLY EMPTY MW/AM CHANNELS

One other drawback is the one I deal with here in this blog post: Low Headphone Volume on nearly empty AM band channels.

The PR-D5's stereo headphone jack has drop-down resistors that reduce the volume so much that Long Distance AM stations can be virtually inaudible on some channels, mainly in the 'Top Band' or 'X-band' between 1600 and 1700 khz, where there are less stations than usual, and much weaker overall signal strengths (Although some radios' performance drops off above 1600, that is not the case with the PR-D5 -- the radio performs the same across the band).

This is frustrating, because the radio's audio chip is capable of putting out almost a watt. Yet on some nearly empty channels you will hear nothing -- even the static is barely audible.

One night, soon after buying this radio, I found myself tuning to 1650 Khz and cranking the volume all the way to the maximum to try to hear a very weak station from far away, a NOAA Weather station from the Oregon Coast. I could barely even hear the static on an otherwise empty channel. Bad deal.

I tried removing the drop-down resistors on the radio's stereo headphone jack. Woops. :-(

I nearly ruined the headphone jack trying to do that -- the surface mount parts were impossible to bridge without special techniques. In my ineptness, I wiped out the left headphone channel. Obviously -- I am not good with messing with surface mount wiring. :-(

The open backed Sangean PR-D5 with the new mono headphone jack wired in parallel with the radio's right speaker. You can see the jack in the middle of the back of the radio, with two wires going to the speaker connections of one of the speakers. I used a mono jack because a) I had one, b) it would be much, much easier to wire it, and c) the AM radio band broadcasts in mono anyway. If you look closely you can see silicone glue, which helps keep the jack in place. It was a tight fit into the hole I drilled, but I used the glue just to keep it from ever moving.

A MONO JACK IN THE BACK OF THE RADIO WORKED BETTER

So I did something better (at least for me): I wired a mono headphone jack in parallel with one of the speakers. That way, through a very simple wiring procedure that only took 15 minutes, I was bypassing all the drop-down resistors, and could take advantage of the radio's full volume if needed (well, half volume -- it's a loud radio!)

The mono jack worked great because a) it was simple, and b) AM radio is mono, anyway.

After doing this mod, all of a sudden my headphones were usable for Long Distance listening ('DXing') the mostly empty channels like 1650 and 1660, just as in all my other radios.

DOING THIS SIMPLE MODIFICATION

The first step, naturally, if you want to add a mono headphone jack is to open the radio.

First, remove the two tiny screws that lie just under the top of the back of the radio. They are embedded in the silverish part of the radio just behind the whip antenna. When you have taken them out, throw them away, or toss them into your junk parts box, because they are so cheap the heads will probably strip if you ever have to take them out again. Trust me.

There are five main screws that hold the PR-D5's case together. Four of these screws are easily seen in the back of the radio case -- the fifth one is in the battery compartment. These screws are decent quality plastic screws and are relatively easy to take out. Once the five main screws are out, the PR-D5's back comes off easily -- this radio is designed quite well, like many old Japanese boomboxes were -- built for easy repair if needed. No prying, wiggling, etc. needed.

Once you have the back off, drill a small hole in the back of the case, just above the right speaker, using a drill bit, and you can use a circular file to make it just big enough for your mono headphone jack if the fit is too tight. Press the headphone jack through the hole, and wire a wire to the jack from each of the right channel speaker's terminals (I used the right speaker because there is more room there).

Use a little silicone glue to secure the headphone jack to the back of the radio, by dribbling a small bit of it around the outside of the jack on the radio back's inside surface. Leave the back off of the radio for a few hours, or overnight, to let the glue set.

Reassemble the radio and you're ready to 'DX' (do some Long Distance listening) with headphones.

The AF chip (a UTC2025) in the new PR-D5's has internal thermal protection, according to its datasheet. So you can wire a mono headphone jack into the audio chain and not have to worry about the AF chip frying if somehow it were able to get shorted. And chances of shorting a headphone jack by just using your headphones is pretty minimal, anyway.
The only caveat using a headphone jack in line with the speakers is you have access to about 800 MW of audio -- so CAUTION! Make sure you don't turn your volume all the way up when using headphones! You won't need that much, anyway!

Always be careful when using headphones on a radio! You've only get one set of ears!

I never have to turn my radio's volume control higher than 1/3rd or so while Long Distance listening.

The back of my PR-D5 after modification. The new mono headphone jack I added can be seen in the middle left part of the radio, just above the battery compartment door. It's unobtrusive, and works well.

UN-NEEDED FOR FM RADIO LISTENING

The modification I just described only really helps with the AM band. FM is loud enough through headphones that no modification is needed. FM stereo sounds rich through this radio -- the fact it is a mini-boombox helps, also. It's loud enough to fill a small room with high quality sound, and loud enough to listen to sports outside while gardening, etc.

THE PR-D5 IS A GREAT AM BAND LONG DISTANCE RADIO

The PR-D5 is probably my best overall AM Long Distance radio. It will hear practically everything there is to hear on the band, even without an external loop.

I still use my other MW Long Distance radios, though, for fidelity, convenience, or just for the heck of it.

USING A LOOP WITH THE PR-D5

Using an external loop with a PR-D5 (at least the newer PR-D5's with the digital IF chips) can be tricky. Some guys have complained about the PR-D5's 'soft muting' making it difficult to use with a loop while Long Distance listening. I haven't had much problem with any muting. But there's a trick to using an external loop with the PR-D5, because of the way the radio's DSP IF chip 'tunes' to the external loop.

One of the chips (either the digital IF chip, or the 4066 'Quad switch' chip -- a gating chip in the audio chain apparently used for noise reduction) seems to mute the radio during noise voltage spikes, or quick volume peaks. When the noise spike is done, it goes back to normal. And, from what I've read, SiLab digital IF chips like the one in the newer PR-D5's also apparently 'tune' to the antenna, peaking signals as you tune up and down the AM band. So maybe when you use an external loop, the digital IF chip is trying to 'tune' to it as well, slowing the process.

Either way, what I've found is with a PR-D5 you have to keep the external loop farther from the radio than you do with other AM Long Distance radios.

With a PR-D5, you keep the external loop away from the radio by about 5-6 inches (120 mm to 150 mm), and you can peak the signals with the loop OK. You have to fine tune the loop a bit slower, though, to hear the signal peak through the speakers or headphones.

I've found an external loop can boost the signals on a Long Distance AM signal maybe a DB or two.

But you've got to keep the loop about 5-6 inches (120 mm to 150 mm or so) away. Any closer, you don't get any benefit, and peaking the signal with the loop is nearly impossible.

EDIT: YOU CAN ALSO USE A LOOP RIGHT IN FRONT OF THE SPEAKER.

A couple years after writing this article I discovered -- by accident -- that if I placed my Select-A-Tenna right in front of either speaker, the PR-D5 will boost very well. It is as strong as it is 5-6 inches off the side of the radio. I don't know why I didn't try this earlier. Behind each speaker is where the twin coils are located (as you can see in the above photographs), so this makes sense.

So if you have a PR-D5, and need a boost in your DX signals, try placing your external loop in front of the left or right speaker on the radio. Sometimes this works better than having the loop to either side -- and other times, having the loop to either side of the radio is better. But at least there is another option.

The Sangean PR-D5 with a Kindle plugged into the AUX IN jack on the left side of the radio. It has plenty of volume for listening to online music.

ONLINE RADIO LISTENING USING A TABLET AND THE AUX-IN JACK

I frequently use my PR-D5 to listen to Foreign and domestic radio stations by plugging a cord between the headphone jack of my Kindle Tablet and the PR-D5's AUX IN jack.

The PR-D5 has plenty of volume, and the AUX IN jack is stereo, so you have stereo sound. The radio is loud enough to use outside on the patio, or in a room. 

Foreign stations I usually listen to are the Norwegian NRK stations (P3, P1, NRK Norsk Folkemusikk, and sometimes non-NRK stations NRJ and Radio Tromsø) and a couple stations from Sweden (Sveriges Radio P1 and P2). There are Saami language programs on both Sveriges Radio and NRK that I also listen to. The Saami programs are very interesting, because they play a lot of tracks made by popular and rising Lappland musicians. I listen to these and other stations using TuneIn, as well as directly off of the stations' websites.

SANGEAN PR-D15

There is a newer model of Sangean radio that looks like the PR-D5 that has a few extra features. This radio is called the PR-D15. It has a SiLabs digital IF chip in it. My guess is that when Sangean started making the PR-D15, they changed the circuits to the PR-D5 at the same time, saving money at the factory (both radios are basically in the same case).

For PR-D15 owners, the external loop trick I mentioned here may also work.

It's also possible the mono headphone modification would work, too, if you have a PR-D15 and find the headphone volume is too low on some AM band channels. But -- never having used a PR-D15 or seen the inside of one, I have no idea whether such an addition would be necessary.

Finally, remember that if you try to do any modifications, or take apart the radio, you are undoubtedly voiding your radio's warranty.

Ball Cat says happy Distance Listening!

Well, Happy Long Distance AM band listening to any 'DXers' out there -- and, for those of you non-radionuts out there who suffered through this post, hope you are had a great Summer, and are having a great Fall also! Halloween is getting closer here in the U.S. (and I know there are some other countries that celebrate Halloween also).

Have a safe and happy Fall!

CC

RE: POWER BUTTON ISSUE

Addendum, 8-12-2017: After a couple years of use, I've noticed an issue with my PR-D5, albeit a minor one: when turning it on, sometimes the radio wants to go to the 'Alarm' setting function. Why this is, I don't know. The radio still turns on as usual, though, and otherwise operates perfectly. I think it may be a software glitch -- the radio thinking the power button is the 'alarm' button. Or it could be a small static electricity caused glitch. Either way, the power button still feels solid, as do all the other buttons on the radio. I still use the radio every night while writing, sometimes listening to DX or regional stations' programs through either the speakers or headphones. I still think the PR-D5 is a good value for the money.

Addendum, 8-24-2017:
After changing the batteries to do some Solar Eclipse MW DXing (my power meter was down to one bar for several months when the power button thing started happening) the power button glitch disappeared. Fingers crossed. It's possible the low batteries had something to do with the 'glitching' of the power button. The glitching was happening even when on AC power, but the batteries may still present themselves when the radio is plugged in... Not having a schematic to this radio, I don't know. All I know is that the glitching is gone. Works good enough for me. :-)

Addendum, 9-9-2017:
My power button still is a little bit funky. Sometimes it still goes to the "ALARM" function, then when I press it again it goes to the radio. Sometimes when pressing it, it does nothing (more rare). Then I press it again, and it works fine a bunch of times. I think it's the shape of the power button -- it has a concave front -- and also because the button has had plenty of use. I haven't had any issues with the PR-D5 not turning on, just this glitch. I've had no issues whatsoever with the other, rounder buttons on the front of the radio -- some of which I've used almost as much, and even more. The glitch doesn't happen all the time, so I don't think the button is failing, or it would probably happen all the time. I may end up installing a rounder button, eventually -- one with a more positive feel -- like the rest of the buttons on the front of the radio. Or I will super-glue a round plastic surface to the front of the power button for more positive action.

Also: I've noticed that a Select-A-Tenna works very well right in the front of the radio. You don't have to place it 5-6 inches away from either side. I just never thought of trying the loop in the front of the radio before. The sweet spot seems to be in front of either speaker -- probably because that's where the loopstick's twin coils are located. (I've added this information inside my article). For some readers, placing an external loop may be easier off the front of the radio than a few inches to either side.

Addendum 10-20-2017:
Spraying some tuner cleaner down the sides of the power button seems to reduce the issue. Like I've said before, the power button never has NOT worked. I use the PR-D5 every night and it always works well. It's just that the power button is shaped poorly, and over time it probably needs tuner cleaner or exercising. Note to Sangean: Concave front power buttons aren't the best.  :-)

Addendum 10-23-2017

RE-SET / RE-BOOT THE RADIO!

I did a little research online. There isn't much info on Sangean PR-D5 power button issues, but one man said when he hits the 'Step/Band' button, sometimes it acts like he hit a memory location button, and switches the radio to one of the 5 stations in the radio's memory. With me, sometimes when I hit the Power button it acts like I hit the 'alarm' button.

This tells me that it is probably not a physical problem, because the buttons are actually working. It may be a firmware/software problem. The 'reader' program in the brain chip, that scans the buttons, may be seeing the wrong button pressed now and then.

I RE-SET my PR-D5, by unplugging the AC supply, and taking out one battery for about 20-30 seconds, and the power button worked instantly after I powered the radio back up, where before there was a bit of a lag. When you re-set the PR-D5, you have to reset the clock, which isn't that big a deal.

I am hoping this may be the solution. If all it takes is re-setting, that's easier than taking the back off and troubleshooting the button board -- but I don't think the issue is the button board. I've found a photo of a clear PR-D5 -- it looks like the buttons are encased in a board attached to the front of the radio. Fairly securely. The buttons on my radio don't feel loose at all. They still have a firm feel to them. This leads me to think that the issue is possibly firmware, and like with a computer, sometimes firmware needs a re-set. 

I guess I'll have to wait and see. :-) If RE-SETTING the radio is the solution, I will put up a short blog post on here about it to make it easier for other PR-D5 owners to find it.

10-24-2017:
So far, the power button works instantly, and has all day, on battery or on AC adaptor. Fingers still crossed.

Addendum, 11-2-2017:
The power button fix (by re-setting the radio) is still working. The power button works instantly like it is supposed to.
I have added a blog post about re-setting the radio for those interested:
https://interrocknation.blogspot.com/2017/10/how-to-quickly-fix-sangean-pr-d5-power.html

Addendum, 11-16-2017:
The re-boot/re-set fix is still working. Almost a month now. Definitely the reset cleared the issue. :-)

Addendum, 11-19-2017:
I added some info into this article, on the changover from PLL to DSP chipped versions; and added a sentence to this blog entry about the slower than standard AGC making the PR-D5 a little more susceptible to pulse noise. My reboot fix is also still working.

A PET PEEVE: DISCONTINUED PRODUCTS

I don't know what insane idea takes place in the heads of some retailers when they decide to discontinue a perfectly good product that seems to be selling well, leaving you to depend on a worse (or less effective) one.  The only thing more frustrating than that is when a company "improves" a product by making it worse... but I digress.

IT WAS GREAT TEA, THEN WAS DISCONTINUED

A few years ago there was a tea label that had this excellent Vanilla Maple black tea that flew off the shelves. It was a flavored blend of mellow tasting black tea with the right mix of vanilla and maple -- very addicting. Their Apricot Ginger flavored black tea was excellent, also. Full of flavor, mellow, and the black tea used was full flavored and not bitter at all.

Celestial Seasonings makes excellent tea. For a few years they produced a line of excellent black teas like the one pictured above. The Vanilla Maple was released in this same series of teas.

Both flavors of black tea were big sellers. After two years or so -- discontinued. There were other flavored black teas that only lasted a year or two -- then gone.

Another tea company (whose name I've forgotten) had a Nilgiri black tea in tea bags that was excellent. Some of the mellowest, full bodied tea ever to come from a tea bag. The local grocery store that carried it couldn't keep it on the shelves. After about six months: discontinued.

 Celestial Seasonings' "Fast Lane" tea -- another flavored black tea that was very good. It lasted about two years?

One reason for these teas being discontinued was that there was a green tea craze that took over the tea trade, due to some news articles on the health benefits of green tea. Consequently, some tea companies switched from producing black teas to producing green teas instead. However, when they junked some of these black teas, it was a sad time for black tea drinkers. And to a black tea drinker, most green tea tastes like grass clippings.

....AND THEN CAPSAICIN LIQUID BECAME HARD TO FIND

Now for a newer case in point: Capsaicin liquid. Capsaicin is a byproduct of the cayenne pepper, and is used by people who have tendonitis, or used after workouts. For a few years I've been using a form of Capsaicin that comes in a small bottle with a felt applicator. I use it on sore muscles after workouts, and I also have a muscle tendon that acts up now and then, and the capsaicin really helps.

Now, capsaicin products aren't for everybody. The first few applications will really burn for up to a half hour or so. Usually it's best to use a very small amount of capsaicin cream or liquid and then work your way up. 

The Capsaicin liquid that I have been using is in liquid form, and absorbs readily into the skin, and leaves very little mess behind afterwards.

This product works terrifically. But it has been discontinued.

The label has been blurred because my point isn't to slam the drugstore chain -- perhaps they had valid reasons (Low sales nationally? Supplier issues?). It's just that when a good product becomes discontinued, it's frustrating.

The national drugstore chain where I used to buy this useful Capsaicin liquid product decided to yank it about a month and a half ago, which left me to depend on weaker Capsaicin creams that stick to the fingers; don't absorb through the skin as well; don't wash off easily -- and if you rub your eye or touch it by accident, it will burn for half an hour 'cause you didn't get all of the Capsaicin cream off -- because the stuff really sticks to your hands.

A LUCKY FIND

After searching through the pain relief sections of several stores I finally found another Capsaicin liquid available, at a local box store (part of a national box store chain) -- the liquid was probably made at the same factory as the one pictured above. My only other alternatives were the creams and buying the product online.

Kroger brand Capsaicin liquid. Works the same as the brand I used for a couple years that was discontinued at a different store.

It works great. So I got lucky.

I know there is probably some valid reason that some products get discontinued from stores. It doesn't make it any less frustrating to have to change products, though.

Ball Cat disapproves!! :-)

Have a great day, and here's hoping your favorite product isn't discontinued soon.

CC

LONG DISTANCE AM (Medium Wave) RADIO LISTENING

 AM / MW LONG DISTANCE RADIO LISTENING

Since I was very young, when I discovered (by accident) long distance radio signals on the AM radio broadcast band, I've always tended to switch my radios at night from the relatively homogenized blah of FM to the fascinating, nighttime cacaphony of the AM band. 

The Sangean PR-D5, a mini-boombox with Stereo FM and terrific long distance AM (MW) band capability. It can also play online music if you use a cable to plug your favorite streaming device into its AUX IN jack.

AM radio (also known as MW, Medium Wave, Mellombølge, Mittelwelle or Mellanvåg in parts of northern Europe) is outdated: yes. AM radio is ancient technology: yes.

AM radio was the original electronic mass media -- it has been around for nearly 100 years. AM radio isn't stereo, and it has lower fidelity than FM or DAB. It is more affected by atmospheric noise and household electrical interference than FM.

A GE Superadio, one of the best stand-alone AM-FM radios ever made.

It seems the only people who listen to AM in the U.S. anymore are ethnic minorities and sports and conservative talk enthusiasts, along with some religious listeners.

But the AM band can be quite interesting, especially at night, when the signals start rolling in from a thousand miles away or more.

At night I can hear stations from California, Oregon, four Western provinces of Canada, Mexico, Texas, Nebraska, Montana, Idaho, Nevada, Utah, and several other states that are located east of the Rocky Mountains.

At night I can hear sports events, sports talk, Mexican, Chinese, Portuguese, SE Asian and South Asian music, Classic country and some oldies music, and of course the usual serving of news, news/talk, conservative talk and religion (both in Spanish and English). And on a few stations (at least two of them I've heard numerous times over the past few years -- one station in Eastern Washington and another in Arizona) I've heard Native American music.

There are also public radio stations on the AM band: there are several in Oregon which broadcast the NPR network and BBC news overnight, and also at least two CBC stations come in well from Canada, and the CBC has excellent radio programs.

One can hear long distance AM stations year-round, but during winter this long distance reception is usually much greater.

Some people can't stand the sound of AM radio signals phasing and flanging as they bounce off the ionosphere. But there are some who do. It's like literally hearing the signals roll and reflect off the ionosphere, phasing their way to your radio's antenna from somewhere 1000 miles away or more. The stations literally have a far away sound to them.

A home-built box crate loop antenna with about 110 ft. of wire wound around a plastic milk crate. The tuner at the bottom corner of the crate was taken from an old, junked radio. It tunes the loop to boost the signals. The antenna needs no power -- it all comes from the radio signals themselves. The portable radio inside is a Radio Shack DX-350 AM-FM-SW-LW radio with good performance, and terrific sound through headphones. Using a set-up like this, stations from all over Western and Central North America can be heard from the Pacific NW.

Some AM listeners try to see just how far away they can hear a station. I've heard stations from Korea, Japan, and Alaska (although very, very rarely). I've heard US stations as far west as Hawaii and as far east as Cincinnati, Detroit, Nashville, New Orleans, several cities in Texas, and Chicago.

One early morning I heard an AM station from Mexico City (almost 2300 miles away), just on my old boombox.

I've heard Cuba, and I've heard other places in Mexico, and a couple stations in Central and northern South America. To hear many of the farthest stations I used a box or spiral loop antenna and sat it near the radio, boosting the signals. Sometimes those stations (Mexico, Cuba) were audible just on the radio itself.

A small map showing the locations of AM band / MW stations I've heard (green dots)  on radios like my GE Superadio, Realistic TRF, and a Sanyo Boombox. Some reception was with help from an external loop antenna set near the radio (the red line on the map came with the map. Unfortunately, I've never heard any AM station from Australia).

SCANDINAVIAN DXers -- HEAVY DUTY MW Long Distance Listeners

In Europe, people can easily hear North Africa and the Mideast on the AM / MW band.

In Norway, Sweden, and Finland there are MW radio nuts who use high tech radios and antennas hundreds of meters long so they can hear AM stations literally all over the world. They are probably the most well known MW / AM band aficionados in the world -- true 'DXers'.

The term 'DXer' is a radio-nut phrase which means "distance listener". It comes originally from that ancient form of communication: Morse Code.

The Scandinavian MW DXers take advantage of the Northern winter's polar night to 'DX' the Medium Waves, sometimes all day, as it can be night time 24 hours north of the Arctic Circle). Some of them travel to far northern listening sites (Andøya, Kongsfjord, Vardø, Lemmenjoki, Aikhiniemi, etc.) where they string out very long antennas 100's of meters long, and do nothing but drink beer or wine, eat good food, and listen for stations from all over the world.

There are blogs by Scandinavian MW DXers online. I actually discovered blogs and blogging by running across a couple of the Scandinavian DX blogs about three years ago, when I was doing a search on MW DXing. The link below has a list of blogs written by these DXers in Norway, Sweden, and Finland. Some of the blogs are mostly lists of stations they've heard. But sometimes they also post photos of their scenic locations (and dinner -- including reindeer steak?!):

http://nordicdxblogs.blogspot.no/

In the early 1900's most radio listeners were long distance listeners. This was back when radio broadcasting was a new technology, and was AM band / MW only.

Many modern radios like the Sangean PR-D5 have an AUX IN jack, and you can plug in a tablet or other device to stream music through the radio. In this picture I have my Kindle streaming the Norsk Folkemusikk DAB channel from Norway.

INTERNET STREAMING AND GEO-BLOCKING

Today, of course, any 'long distance listening' is all done by a tablet computer or smart phone. You just use an app like TuneIn, IHeartRadio, or Streema to listen to a station from another part of the U.S., Canada, or another country. And -- many listeners are abandoning radio altogether for music services like Pandora and Spotify.

Unfortunately, many stations use geo-blocking to keep people living in other areas from listening to them, because of internet costs. I've noticed that some stations on TuneIn are missing because they are geo-blocked. You call up the station and hear the introductory advertisement, then you hear a tone and a message saying that "this radio station is not available in your country".

Increasingly, radio stations in the U.S. are geo-blocking their streams, limiting them to just the local metropolitan area, because of streaming and royalties costs.


So if you want to hear a football or baseball game broadcast on a radio station from a nearby city, the internet is becoming less useful, and at night especially, the AM band can be useful for that.

Several headset radios, which are often available at thrift stores. Sony models, like the ones here, work well on the AM band as well as the FM band. The grey one at right, the Sony SRF-59, is available in box stores for around $20 here in the U.S. One AA battery in the SRF-59 can last for several months, making it a great emergency radio.

OLD TECHNOLOGY, BUT STILL FUN

Long distance AM radio listening is kind of like astronomy through a telescope -- it's much easier to use the internet to get the same thing. But often using the original technology can be more fun.

My GE Superadio 1 (also the first photo I took with my Fuji snapshot camera). I had it in my car because the car stereo fried. I bought this radio at a local thrift store a few years ago for $5.99.
 

Some guys like to keep lists of every station they have heard. I have a list, but I'm not as intense about it as some guys are. There are also listening clubs, but I am not a member of any of them. There are a few radio-enthusiast internet forums I go to, but that's as involved as I get into the hobby.

I just enjoy listening to the signals from far away as I am reading and having tea.

The GE Superadio II, the last version (F model) built in China. This was my kitchen radio for several years. Last year, the radio took a dive off the refrigerator. The radio still worked perfectly. GE's are built like tanks!

If you are interested in listening to long distance AM / MW radio, you don't necessarily need a Superadio or other 'hot' radio -- even a clock radio or boombox can be good for long distance listening. I have a Panasonic clock radio that is really good, and a couple Sony headset radios I have also work well. During the 1980's through the 2000's the technology in boomboxes and clock radios improved quite a bit, and some everyday standalone radios will pull in a lot of signals, like the Sony pictured below.

The Sony ICF-38 is a portable AM-FM radio that is very inexpensive (around $25-$30 US in some box stores), which sounds good (even on AM) and works really well, and is really easy on a set of four AA batteries -- it's rated at 82 hours with alkalines, although with my radio I got more than 5 months out of a set (I use headphones a lot when DXing with it, though). I sometimes use my ICF-38 to listen to football games outside while doing yard work, and I often use it for Long Distance AM listening, too, as it is a very good DXer. PS -- When using an external loop with this radio, the best place to place it is in front or in back of the tuning dial, which is where the internal antenna is located (although a loop will also work off the side of the radio.

IT'S AN INEXPENSIVE HOBBY, TOO

Long distance radio listening -- like astronomy and some other hobbies -- may not be for everyone, but it can be a fun way to spend an otherwise dreary Winter evening, seeing what can be heard. Like fishing, it can often be unpredictable. And it is a cheap hobby. The only cost is the cost of a radio (which many people already have) and maybe the cost of the batteries to power it up -- it's one of the cheapest hobbies out there.

Addendum, 11-2017:
I probably should mention here that there are several other MW DX related blog posts on my blog here. I have reviews of several of the radios I use for MW DXing (mostly portables), including some tips on maintenance and very simple repairs. Thank you to all who have read this article and have checked out my blog. Good DXing to each and every one of you. 
CC 11-25-2017

Addendum, July 22, 2022:

As it took me a while to figure out how to respond to comments, I decided to respond here to Ayman' the MW DXing Vet's question below (in the comments) about which Sangean radios I think are best on MW. It's probably pertinent to add it here, as my blog article is all about MW/AM DXing.

It's hard to give one answer, and it is a toss-up, really. The PR-D5 is probably the best overall. It's hard to beat a DSP radio with a 200mm, dual coil antenna. The audio is a little muddy at times, but it's not bad, and the radio does reduce noise. 

However any Sangean radio will do well if you have an external loop. I have a PR-D18 (a small, grey Sangean radio with AM/FM and a DSP chip, just like its bigger brothers), and it DXes well with a loop, and DXes OK without one. It has a slightly higher bandwidth than the PR-D5, and is very pleasant to use with headphones. My PR-D14 (a mono PR-D5, basically, with a smaller loop inside) is about as good as my PR-D5. Side by side it's hard to tell their reception apart.

The DSP chip inside these radios is a fairly good equalizer.

I don't have every recent Sangean MW radio -- I've read good things about the PR-D15 (a PR-D5 with a tone control -- I can see how that would be very useful!), and I've read a lot of great things about the PR-D4W, which is a small portable with great performance -- or so they say -- and has several bandwidths -- which also would be very useful.

For older Sangeans, the Sangean ATS-909 / DX-398 is an EXCELLENT MW radio, as is the Sangean-built and designed Realistic DX-375. Both of those will DX well even without external loops. If the new ATS-909X is as good on MW, it probably is a winner.

Also, I don't know if the Sangean ATS-505 is still being made, but it's very good on MW. I live in a low signals area, so I usually need a loop with it to really DX. But it has excellent sound (especially through headphones) and the selectivity is very effective.

I hope this answers the question. I do indeed hope to get a PR-D15 and/or PR-D4W sometime in the future. If and when I do, I definitely will post an article about them, and I will also include comparisons to other radios.

Peace to all,

Chris