From: David Moisan
Subject: GE Superradio FAQ
Date: Jun 10, 1994
Newsgroups: rec.radio.broadcasting

The GE Superradio Frequently Asked Questions List -------------------------------------------------

compiled by David C. Moisan, N1KGH

Version 1.0, June 1994
In this FAQ, I've assembled the net.wisdom on one of the most popular
and (IMHO) best radios for AM (mediumwave) and FM DXing, the General
Electric Superradio. There were three versions of the radio, and
the latter two (II and III) are covered here.

Included are several Superradio mods that I know about; if you've
modified *yours*, let me know about it and it'll be included here.


** What is the GE Superradio? Does it do shortwave?

The General Electric Superradio III (abbreviated SR III) is an AM (mediumwave)/FM radio designed for long-range, high-fidelity
listening. It's the radio of choice for many AM and FM DXers.

It doesn't do shortwave. What it does do is tune the AM (mediumwave)
band from 530-1705 KHz and the FM band from 88-108 MHz; it doesn't
receive FM stereo (nor AM stereo either). There's a wide/narrow
switch for AM reception. It has an excellent sound system, with a 2-
way speaker and bass and treble controls. Unlike most AM/FM radios
the SR III has additional RF stages, a big (200 mm) ferrite loopstick
for AM, and an external antenna jack.


** Where do I find one?

The GE Superradio is available from many retailers, including K-Mart, Lechmere's and Costco, to name just a few. Bennett Brothers is
at least one mail-order source for the radio; the address is at the
end of this FAQ. Street price is between $35-55.


** I'm outside the US. How do I get a Superradio?

Richard Hunt:

"For UK residents, the easiest way to get a GE Superadio is to order
one from one of the dealers who advertise in the World Radio TV
Handbook, for example Universal Radio in Ohio. The easiest way of
paying is to use your credit card. Most companies accept Visa, Access/MasterCard and American Express. The major added cost will be
shipping: surface mail will add USD 20 or so (and may take 6-8 weeks),
airmail up to USD 50 (delivery in 10-14 days). UK Customs & Excise
will add import duty and VAT, which will be collected by the post
office when they deliver (they will charge GBP 5 for this "service").

Bringing a Superadio back from a trip to the US is also possible, but
it is quite large, and you may have trouble with airline/airport
security. DO NOT pack it in checked baggage. Carry it on in hand
luggage and be prepared to demonstrate it working. Go through the RED
channel at Customs and pay the VAT. Getting caught in the Green
channel will most likely result in at least public embarassment and
having to pay up anyway, at worst, confiscation of your Superadio,
prosecution, a heavy fine and a criminal record.

The major problem is likely to be power supply. The mains transformer
on the Superadio works off 110 volts, 60 Hz. The US plug molded onto
the wire won't fit a UK socket - just as well as UK mains is 240V,
50Hz. Feeding 240V into a 110V device will damage it instantly beyond
repair. There is no 9V dc input, so you have to rely on batteries,
obtain a 240v-110v stepdown transformer or modify the radio
internally.

[Bennett Brothers will ship the SR overseas; their address is in the
appendix.]

** The Superradio III? What happened to II? Or I?

The SR III is the latest version of the radio. The SR II, which
many people still own, had a different cabinet and AM coverage only to
1600 KHz; the SR III accomodates the expanded AM band (if it's ever populated...) The II does not have a AM wide/ narrow filter switch.

There are some technical changes as well; the III uses varactor
tuning compared to the II, which uses a conventional variable
capacitor.

Dave Markson has this to say about the II vs. the III:


"I have an original Superradio and just bought a SR3 (modified on FM
with a 110/280 KhZ IF filiter, and SCA by SCS Radio Tech). As for MW,
here are my findings:

1. The SR3 has much better sound.
2. Although the SR3 has a wide bandwidth position, it is almost
useless, but does increase the highs on local stations. The normal
position is close to the bandwidth of the original SR.
3. The SR3 is more sensitive (by a small amount)
4. The SR3 has about the same selectivity of the original SR, my
findings show it a little bit less selective.
4. The SR3 workmanship is not quite as good as the original SR.
5. The SR3 is harder to tune. Where as the original SR band was spread
out pretty evenly across the dial, the SR3 uses 1/2 the tuning dial
to go from 530-1000kHz, then crams the rest on the right half of the
dial. Tuning the upper portion takes a very steady hand! Calibration
is terrible also.
Note: I bought a Select-A-Tenna, and it improves reception on both SRs
A GREAT DEAL. Well worth the $40-$50 (hmmm, same cost as the SR3)

As for FM, here are my findings:
1. The SR3 has much better sound.
2. The original SR is MUCH more sensitive than the SR3. It is possible
that this is due to the modifications, but I'm not sure. Anyone
comment on this?
3. The 110/280 kHz IF filter is a great idea. The SR3 has a stock 180kHz filter.
4. Using SCA is great. I am a little disappointed that there are so few
SCA programs in the greater Boston area. Most stations are transmitting
data on their subcarriers. SCA requires a very clean local signal.
There is no DXing SCA stations.
5. SCS does a very clean, professional mod. [No relation to SCS]



** What kind of performance can I expect from the Superradio?

Compared to the average radio, you will get better reception.
Over a few weeks of listening, I compared the SR II to my Realistic
DX-400 (with an external antenna), listening both in the
day and at night; I live (directly) on the East Coast, 25 miles NE of
Boston, Massachusetts. The results:

Daytime AM (mediumwave)--I found a dramatic improvement. I can
regularly get several New Hampshire news/talk stations, including WNBU
900 and WZNN 930, that come in weakly with the DX400, if at all. The
SR's antenna really cuts down the noise that is ever-present during
the day.

Nighttime AM (mediumwave)--When the ionosphere is 'on', almost any
radio will hear DX. But the Superradio receives DX more consistently,
and with better selectivity than any other radio I've used.

Although the Superradio has only imprecise slide-rule tuning, I can
regularly resolve different stations 10 KHz away from each other. And
unlike so many shortwave portables, there's no overloading, at least
not on the internal antenna.

Also, as mentioned previously, the radio has excellent sound that'll
enhance your listening in almost any situation.


** What kind of outside/external antenna can I use for mediumwave?

People have spoken well of the Select-A-Tenna, an external loop
antenna, sold by Grove. This is about $50.

I've used the SR with my Carpet Loop antenna, with good results.
A few years ago, I had some very interesting results using that
antenna for MW with the DX400; I once was able to receive both
WJR and Radio Reloj on 760 KHz at will by flipping a knob on the
antenna.

In general, loop antennas are a good choice for mediumwave
listening. The National Radio Club publishes loop plans; their
address is in the appendix.


** What about those reports I hear of problems with the SR III?

Some people have reported poor sensitivity on the III when it was
first released. Radio World (3/24/93) quoted a spokesman for Thomson
Consumer Electronics indicating that some early models of the SR III
have severe sensitivity problems.

These early models had the following date codes, a 4-digit code found
on the box or in the battery compartment: (the first digit is ignored)
x201 through x241.

** The dial calibration on my Superradio is off!

This is a common problem with slide-rule radios such as the SR. Many
of us who are used to digital displays are thrown by this.

Andy Sennitt suggests using graph paper to plot frequencies of known
stations versus the dial log, which is marked from 0 to 10, in tenths,
on the Superradio. I'd suggest graphing small segments of the band
(say, 800 to 900 kHz), until you get the hang of it. One can get
within 10 kHz, which is good enough for most purposes.

(I last did this trick with a Realistic DX-160, which I used aeons
ago. How soon I forget. :))


** Can the Superradio be modified for SCA reception?

Yes. Several manufacturers sell kits and assembled boards that can
be used with the SR. SCS and Ramsey sell boards, while Bruce Elving
sells complete Superradios with the modification. Here are Joe
Jesson's comments on the SCS board:

"I recently ordered and received three SCA demodulator boards from
SCS Radio Technology after noticing an advertisement in Radio
News. Bruce Elving's SCA design uses a CA3089 IF/detector chip and
a PLL (I designed his XR2211 PLL SCA demodulator) SCA. Bruce also
sells FM receivers modified with the boards.

What was interesting about the SCS SCA board design, while it uses
a CA3089E IF chip also, a multipole filter in front of the 3089
decreases main channel crosstalk interference (by 60 dB). David's
board is of excellent construction, with no jumpers and small size to
be inserted in an FM receiver's FM detector stage (before deemphasis
attenuates the SCA signals).

Anyway, three pretuned boards are available from SCS, 57Khz, 67Khz,
and 92Khz - $20.00 each, $60 plus $6.00 P&H for all three. I am
satisified with the design and construction of each board. One
area of modification I would make is to monitor the SCA signal's
multipath and level with an x-y monitor. Use pin 13 of the 3089
chip for a signal level (scope y) output and pin 7 for the y axis
output. Of course levels must be set to set vertical and horizontal
traces. A flat vertical line, max amplitude, is the ideal signal
for tuning. A "wavy" line illustrates multipath. This is a great
tool for tuning FM signals...

** Is a service manual available?

According to my SR II manual, service info is available from GE
Publications Ordering at (502)-361-0987. To get service, GE
recommends you write to:

GE Consumer Electronics Products
Manager, Consumer Relations
P.O.Box 1976
Indianapolis, IN 46206


The address for service manuals is:

Thomson Consumer Electronics Publications
Customer Service
10003 Bunsen Way
Louisville, KY 40299
Phone: 1-502-491-8110

Price of the manual in 1993 was $6 plus $3 handling; it's recommended
you call first to confirm pricing. When ordering the manual, be
sure to include the suffix, as the service data is revised with
production changes. (My SR II is #7-2885F; the SR III is #7-2887)


Appendix A: Fixing and Modifying the Superradio ------------------------------------------------

Disassembling the Superradio II
-------------------------------

[Summarized from comments by Bruce Bacon, Ralph Brandi, R. Hardin,
and Gregory Doerschler]

1. Remove ALL knobs in front, including the tuning knob, by pulling
them straight off. A plastic fork is a good tool to use and won't
bend the shaft. Be patient but firm--the knobs may be glued or taped
on.

2. Remove the back screws, except for the antenna screw. Don't
forget the screw in the battery compartment.

3. Remove the front cover by pulling it from the rear and _upwards_
so that it clears the power switch. The power switch is fragile, and
a real bear to fix if you break it, so be VERY careful here. You may
want to try removing the button from the switch *carefully*.


4. If you do break the switch, here are R. Hardin's instructions for
repair:

"The power switch is very entertaining to reconstruct, especially if
you don't have all the pieces. Unscrew it, take off terminal plate
if it's still on (mine wasn't), find little metal slider thingy
that grips the terminals on the inside - it slides between terminals
1 and 2, or 2 and 3. There might be two of them, I only found one;
shake the radio over some surface where you can find it when it
falls out. Put it on terminals 1 and 2 (the off position).

The mechanical parts can be removed now for experimentation:
The button, switch case, and a plate with a funny wire in it
that's supposed to be in the back of the switch. There's,
what, 8 ways to try assembling it. Well, 4 ways if you
consider that POWER ON OFF has to be legible from the front
of the radio, and only 1 way if the plate is still in the case.
Put in plate with wire, put in button, and see if the button then
has two positions it's happy in, on and off.

(If you have a plate and a wire, instead of a plate with a wire,
there are more ways to try I guess.)

Leave the switch in the off position, which is the only one
it's really stable in without the terminals on, and put the
terminal plate on, the slider fitting into the slot in the
button. You may have to spread the fingers that were
supposed to keep the switch case together a bit.

See how nice the switch works now? Screw it back in, and
swing case back on, putting it on the top first and swinging
it closed. There's a little forcing past the tuning shaft.
Stress the tuning shaft, not the power button!


Fixing the Dial Calibration on the SR II ----------------------------------------

by Bruce Bacon:

I've had my SRII for a couple of years now, primarily tuning on the MW
side of the dial. The SRII is a great MW DX machine except for one
main drawback-dial resolution. Last weekend, I made a modification
which has made the resolution much more livable. If you're into
taking radios apart, give the following a try:

CAVEAT: If you haven't had an SRII apart before, be very careful with
the power switch. Take careful note of what it looks like before
removing it! I gave up and installed an NCR receipt printer rocker
switch (P/N 006-1050121). Much better, but a bit of a hack.

Remove the knobs from the front of the chassis (volume, bass, treble,
tuning). Remove the 6 screws from the back of the chassis. Remove the
screw from the battery compartment. Rock the handle and the chassis
should split open (watch out for the power sw). The speaker wires
connect both sides of the chassis, so be careful.

The pointer is a piece of plexiglass with an orange colored stripe in
the middle. You won't be using the orange stripe anymore for
frequency ident-ification, you'll use the left side of the plexiglass!

Find yourself a suitable scribe (I used an exacto knife). The
receiver should still operate (careful with the power switch) even
though it's opened up. I used batteries to reduce the chance of
electricution.

Turn the dial shaft and start identifying stations. Using the scribe
and the left side of the plexiglass, make a vertical mark every 50Khz
(550Khz, 600Khz, 650Khz, etc). Be careful to tune the *center* of
each station! I made a double vertical line for each 100Khz marker
(600Khz, 700Khz, etc..) I guess you could get fancy and make a mark
every 10Khz, but I think the dial face would get too crowded.

When you've finished with your scribe marks, you can button it back
up. I've found by using the scribe marks in conjunction with the left
side of the plexiglass, parallax is virtually eliminated. Frequency identification is much easier. The main thing is to take your time
and make sure the frequency you think you are on *is* the frequency
you are on!



Improved FM Filter Modification, SR II
--------------------------------------

by Ralph Brandi:

I've found it a worthwhile modification to the Superadio II to replace
the stock ceramic bandwidth filter (230 kHz? 280?) with a narrow
filter 150 kHz wide. It doesn't improve sensitivity, but it does
wonders for selectivity. For instance, with the 150 in, I can now
receive WXPN-FM in Philadelphia, 88.5, (not *well*, but well enough)
right next to local powerhouse WBGO-FM in Newark on 88.3.

I got my filter from a friend, along with some articles in the hobby
press from a couple of years ago. The source I have listed for 150
kHz ceramic filters operating at an IF of 10.7 MHz is:

Hosfelt Electronics, Inc.
2700 Sunset Blvd.
Steubenville, OH 43952
(800) 524-6464
Part # 27-109, $1

I understand there's a minimum purchase, but I don't know what it is,
since I didn't get mine there. I'm lucky if I grab the correct end of
the soldering pencil, but I installed mine this past weekend. I
installed a Radio Shack IC socket in place of the old filter (8-pin
wire wrap, cut in half and with one pin removed, then cut off the
excess wire), then plugged the new filter into the socket.

The filter is a little tough to get to; it's on the second PC board
under the dial. It basically involves disassembling the entire radio,
more or less. It's right next to a "square metal box-shaped thing" as
my friend with the filters put it (yes, I'm electrically incompetent).

Things to beware of:

1. Don't break the power switch. It's a bear to put back together
correctly.

2. Make sure you remove the tuning dial from the outside before you
open the radio. Despite the radio's best efforts to fool you
into thinking that it doesn't come loose, it does.

3. Don't mess with the dial cord. If it comes loose, it's a pain
to get back on, if you can figure out how it goes.

Of course, you shouldn't infer from this that any of this happened
to me.... :-)
--


Sensitivity Fix for some Superradio III's -----------------------------------------

From the March '93 edition of _DX Ontario_:

"Dave Maunder of Brigus, Newfoundland, has had some interesting
experiences with his Superadio. He writes, 'Although an R-5000 is my 'workhorse', I've often used a GE Superadio II for medium-wave
listening. When the Superadio III became available last fall, I
ordered one from Universal Radio. Anxious to do a side-by-side
comparison with the old model II, using only the built-in ferrite rod
antenna for the test, I was disappointed to find that my new model III exhibited a high background noise level and much poorer sensitivity.

'So I disassembled the Superadio III to do a little 'tweaking', and
was surprised to find that performance instantly improved when the 2
halves of the cabinet were separated by the length of the speaker
connecting wires. The noise level dropped drastically, and the
sensitivity came way up. I now could easily hear VOUS, a 50-watt U.S.
Armed Forces station in Argentia, Nfld, on 1480 kHz, and St. Pierre-
Miquelon on 1375 was easy. (This at 1:00 p.m. local time at my home
about 40 miles from St. John's.)

'But when I reassembled the radio, performance deteriorated to the
original level. There seemed to be some kind of interaction between
the speakers in one half of the case and the circuitry in the other
half. I suspected that it was the strong magnetic field saturating the
antenna rod's ferrite core, so I wrote GE asking if they had a fix.

'They seem aware of the problem, and suggested simply reversing the
two leads from the circuit board to the speaker unit. I was
skeptical, but I tried it and their cure worked perfectly. Not only
is the GE Superadio III a hot MW-band receiver, (British, German and
many other European MW stations are audible nightly here on the edge
of the North Atlantic, especially when using my 100-foot long wire)
but, on strong signals, the audio in the "wide" position is exceptional...indeed, very close to FM quality in range and clarity.

'Perhaps this tip might be useful to someone else who buys a GE
Superadio III. Not all units may be affected, but if the noise floor
seems high and sensitivity poor, try reversing the speaker leads!'"

APPENDIX B: Superradio Vendors and Related Accessories -------------------------------------------------------

Here's a list of vendors that sell the Superradio and related
accessories:

Bennett Brothers, Inc., will export a Superadio for you; they have
addresses in both New Jersey and Illinois.


Bennett Brothers, Inc.
30 East Adams
Chicago, IL 60603

Orders: (312) 621-1600
(800) 621-2626


Bennett Brothers, Inc.
211 Island Road
Mahwah, NJ 07430

Orders: (201) 529-1900
(800) 631-3838


SCS Radio Technology
5742 Fairoak
Springfield, MO, 65810
Phone: 417-881-8401

Manufacturer of add-on SCA demodulator board for the SR.

Bruce F. Elving, PhD
c/o FM Atlas Publishing
P.O. Box 336
Esko, MN 55733-0336

Sells Superradios modified for SCA on both 67 and 92 kHz subcarriers.

Universal Radio
6830 Americana Pkwy.
Reynoldsburg, Ohio 43068
(800) 431-3939
(614) 866-4267
SWL Catalog: $1.00

Sells the Superradio


NRC Publications
Ken Chatterton, Manager
P.O. Box 164
Mannsville, NY 13661-0164

The National Radio Club is a MW club that sells numerous plans and
references for MW antennas, including the following:

NRC Antenna Reference Manual, Volume 1
NRC Antenna Reference Manual, Volume 2
Loop Antennas Design and Theory (ISBN 1-878994-06-9)

Send NRC Publications a 29 cent stamp and ask for the NRC Publication
Catalog for current pricing.

Acknowledgments and Thanks
--------------------------

The following contributors had much to do with this FAQ. I thank
them for their help and advice.


Ralph Brandi, Richard Hunt, Andy Sennitt, Mark Gilstrap, Joe Jesson,
Paul R. Mount, Bradlee Beer, Dave Markson, Tim Flannery and Steve
Byan. Special thanks to Chase Cotton for sending me over 300K worth
of archived SR postings from rec.radio shortwave!

This FAQ is dedicated to my late mom, Jeanette. She owned a Superradio
(which I bought for her) and liked it a lot.


Comments and Suggestions
------------------------

I intend to keep up this FAQ and update it as needed. I'm looking
for the following items for the next edition:

* Disassembly instructions for the SR III
* AM filter mods
* External DC power mods
* Any information on the original Superradio

Email your comments to moi...@bronze.lcs.mit.edu. I can be reached
by regular mail at:

David Moisan
86 Essex #204
Salem, MA 01970-5225

Good listening!


--
| David Moisan, N1KGH /^\_/^\ moi...@silver.lcs.mit.edu |
| 86 Essex St. Apt #204 ( o ^ o ) n1...@amsat.org |
| Salem. MA 01970-5225 | | ce...@cleveland.freenet.edu |
| |

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