Boosting the antenna circuit of a GE SUPERADIO 1 & 2

BOOSTING THE SENSITIVITY OF A GE SUPERADIO 1 & 2

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.

A couple blog posts previous, I wrote about my Long Distance AM Radio listening hobby, a pastime I have enjoyed since I was little.

I'm not a heavy-duty AM distance listening enthusiast. I just like to put on the headphones, switch on the portable radio while I'm reading, and tune around and see what's out there.

Sometimes I use an external loop antenna to boost the signals even more. Sometimes I don't bother.

I like to use the GE Superadio because it sounds so good through headphones, and it pulls in stations from distant places. The radio also sounds great through the speaker.

There are three versions of the Superadio, and I have all three of them. All are very good AM and FM radios, and they are still very popular among AM band long distance listeners ("DXers").

I also sometimes use my Superadios to listen to FM, as they pull in some stations my other FM radios usually won't. But for most FM listening, I use my boombox. The Superadio is mostly used for night time AM band listening.

A LITTLE ABOUT THE GE SUPERADIO

The GE Superadio was a radio model GE introduced in 1979. They originally just called it the Superadio, and a super radio it was. It had very good reception on FM, and excellent reception on AM, as well as excellent sound. It was intended for people who wanted to hear stations in other cities and regions -- either to hear a distant talk show, or perhaps to hear a sporting event.

As the Superadio is excellent on batteries (a set of D cells can last months, literally -- I just recently replaced a set of batteries in my Superadio and they had lasted at least eight months), it is great for taking camping, or for disaster preparedness.

In the early to mid-1980's GE updated the Superadio model to the 'Superadio II', which has a tweeter speaker for FM and a couple other small changes.  Then in the early 90's GE came out with the 'Superadio III'. All three models are quite good (although there are some bum III's out there, because of cheap tuner parts that were used in later runs of the radio).

SUPERADIOS ARE BUILT LIKE TANKS

Superadios generally are built like tanks (I've seen a Superadio II take a dive off of a refrigerator and still work normally afterwards, with not even a scratch) -- but the bandswitches on the Superadio 1 and Superadio 2 seem to be the weakest part of the radio. Sometimes the AM band will go dead, because years of switching between the FM and AM bands can pull on the switch's solder connections, and weaken the switch's connections on the main PC board. I haven't had this happen to my radios.

The AFC switch usually doesn't seem to have issues, probably because most FM listeners leave it in that position permanently.

The GE Superadio 1 with the back off, and the main PCB is loosened but still wired to the other parts of the radio -- picture was taken before I added the antenna circuit resistor. The bandswitch and AFC switch solder contacts are in the middle of the main PCB. Those are the ones I hit with the solder gun and added just a little more solder.

I have only done two 'modifications' to my Superadio I and II. That is -- if you could call them modifications -- because they are very minor ones (I haven't done any changes to my Superadio III, as it is one of the better ones).

The first modification I did was to add solder to the bandswitch and then plaster silicone glue around and underneath the bandswitch, to absorb the stress when you switch from AM to FM. On both the Superadio I and II, the AM-FM bandswitch can be a weak point, which is why I strengthened it.

The other minor modification I've done is to add a resistor in parallel with the the radio's antenna circuit resistor, boosting the signal a little. The resistor that apparently determines antenna signal strength, R13, ranges from 47K, to 56K, to 26K ohms on a Superadio 1 or 2 (the lower the resistance number -- to a point -- you get higher gain, and louder signals). The value of the antenna circuit resistor seems to depend on whatever resistors they had available at the factory.

My Superadio 1 came with a 56K ohm resistor, so I just soldered a second one across it to drop the value to around 25-26K. It did not cause a massive difference, but did boost the sensitivity of the radio, maybe by a db or so, without any ill affects. The improvement wasn't huge but was noticeable.

The back of the GE SR1's main PCB with the parallel resistor wired in. You can see the resistor I added: it's the resistor 'hanging' off the bottom edge of the PCB, in the center of the picture -- it is suspended by two short lengths of green hookup wire (it's near that dark orange plastic guard that covers the radio's AC transformer). I just took a 47K resistor and soldered it to some hookup wire, and then soldered those ends to the pads on the PCB, effectively soldering it across R13. There are no ill affects, and the signals were boosted by about a db or so -- not monstrous, but noticeable. The improvement may not be worth it to a lot of GE SR1 owners.

Before, when I compared my SR1 to another SR1 which had a 26K antenna resistor, my SR1 just seemed to be a little lax in reception compared to the other radio. After the resistor mod, they received the same.

If anyone has one of these radios, at the very least it would be advisable (if you have a little electronics repair experience) to at least hit the bandswitch solder pads with a bit of extra solder and then plaster the underside of the switch with silicone glue. You don't have to take the radio completely apart to do this: just take the back off, and free up the main PCB to get access to both sides by moving it when and where needed.

The inside, looking at the top of the main PCB. If you look closely you can see the clear silicone glue (greyish looking gunk) underneath the switch assemblies. Hopefully it will allow me to switch between AM and FM without worrying about the switch breaking and the radio being FM only.

I can't guarantee that it will keep your bandswitch from going south, but I think the glue absorbing more of the stress from switching the switch will extend its life. It's certainly better than doing nothing. Because if you do nothing (and use the switches very much) the stress from turning the switches up and down goes mostly to the solder pads on the PCB. My theory is the plaster of glue absorbs the shock away from the solder pads enough to lengthen the life of the switches.

DISASSEMBLY -- a Little Tricky, but Turn the Power Switch to the ON position

Taking a Superadio 1 or 2 apart is a little tricky. The first thing you do (after unplugging it and/or taking the batteries out) is pull the knobs off the front. Then you turn the tuner shaft until the flat side of the tuner shaft faces towards the bottom of the radio. This makes it easier for it to clear the hole when you pull the back and front of the radio away from each other.

Then you turn the power switch ON. This drops the switch downwards, giving it enough clearance to clear its hole, when you pull the radio's two halves apart -- if you leave it up, in the 'off' position, it can easily wreck the switch.

To get the front and back free, you've got to rock the two halves of the radio's body back and forth a bit, maneuvering them just right until you can wiggle the front and back free from each other. I've had my SR1 apart probably 4-5 times without wrecking the power switch, so it can be done.

However, I did ruin a power switch on my Superadio III because I forgot to switch it to the ON position, and I had to replace the switch with a toggle switch in the back of the radio.

Taking the main PCB off the radio is a bear, but most of the minor things can be done if you just unscrew it from its mounts, and then pull it away from the mounts carefully, making sure to keep your solder gun or iron away from the dial string if you do any soldering.

Unfortunately, I really can not describe well enough a step by step description of how I did my minor mods. I'm really lousy at describing such things. And to make sure you add the extra resistor to the radio to the right connections, you'd need access to a good schematic or wiring diagram of the radio - which I am unable to add to this blog article.

So this blog article isn't intended as a step-by-step guide, because I'm so lousy at that. But I just put this article on here to give GE SR1 owners an idea of a couple easy things they can do to mod / preserve the operation of their radio.

If you have one of these radios and are interested in doing minor mods, the best thing is to look at the excellent GE Superadio Tech page, http://earmark.net/gesr/sr1.htm , where there are numerous excellent photos, schematic and other diagrams, and step by step descriptions of taking the radio apart, and other fixes that the man who runs the website has done to all three Superadios.

A TERRIFIC EMERGENCY PREPAREDNESS RADIO

Although Superadios are getting rarer to see at thrift stores, they can still be found from time to time. And -- of course -- they are still available used on places like EBay. Superadios are excellent for camping and also for emergency preparedness. In a disaster, when there may be no electricity for smartphone and laptop chargers and the like, and cell services and internet services are down, a portable radio like a GE Superadio is a great asset for receiving news and information, especially when batteries last so long.

I have featured GE Superadios in bit parts of two of my novels in progress: one of them is a disaster novel, where a family uses a Superadio to hear information because the power is off all over the U.S.. In the other novel, one about a homeless guy, a GE Superadio is his only form of entertainment.

My GE Superadio II, the last version (F model) built in China. With the Superadio II, GE added a tweeter, and put a smaller sized metal tuner inside the radio, lightening its weight a little (and probably lowering costs). 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.

I made my Superadio II a little more sensitive by adding some resistors in parallel, dropping the value of R13 from 55K ohms to 38K. The resistors can be seen in the center-right of the picture, soldered together. I used as many as I did because they were all I had at the time. They are soldered to the back side of the second PCB, the upper one with the tuner mechanism on it. Like with my Superadio 1, the increase in performance is small but noticeable.

If you look closely you can see a small slot I filed at the bottom of the tuner knob's shaft hole, to make it easier to get the radio apart in the future if I need to fix it. The slot makes it easier for the shaft to clear the hole, and makes the radio come apart easier because of it.

Here you can easily see the silicone glue plastered beneath the bandswitch as a preventive measure -- to absorb shock and keep it from disfunctioning in the future. The silicone glue and bandswitch are to the center-right of the picture. The chip in the middle of the PCB does most of the radio's electronic 'work' -- RF and IF amplification as well as providing power for the speaker. The small metal cans with colored coding  on them are the "IF cans" that help the radio's tuned circuits work. 

OLD TECH BUT BUILT TO LAST

GE Superadios are old technology, of course. But they are built to last.

My neighbor's teenage son has gone through four different cell phones, two Mp3 players, two laptops and a tablet (two of them broken) in just two years. Meanwhile, the Superadio 1 in the above pictures was built 34 years ago, and the Superadio II just above is probably 24 years old -- and they both still work just like new.