For some time now I have been plagued with interference to my FM signal as I wander around the 8Z compound listening on my Walkman. I have long thought that this was from commercial FM stations with HD but as I thought about it things didn't add up. For one, the interference was only heard indoors on the first floor and not outdoors where my signal is weaker and the FMs are stronger.
The interference is a buzzing sound similar to the intercarrier buzz on old TVs. Long story short, the offender is my refrigerator! It has an electronic brain which apparently is not very well shielded for escaping RF. The interference even changes character when the door is opened. Of all the other gizmos around here with electronic controls this is the only one I have found to cause FM interference.
On a brighter note I solved a problem I have been having with my 69 year old BC-1004-C radio. Of late it has been showing unsteady signal strength readings accompanied by hisses, crackles, pops, and hum in the audio. It is no trivial task to pop the hood on this radio but I finally got around to it and upon removing the bottom cover I noted quite a bit of oil on the sheet metal. The oil came from a bathtub capacitor and is a sure sign that the capacitor is failing. After almost 70 years the rubber seals failed. I replaced this triple section cap with three tubular caps I had in junk, cleaned up the oil, realigned the AVC tuned circuit and the radio lives again with stable meter reading and no noise in the audio. This isn't the first cap that failed in this radio. In the past some wax dipped caps shorted and took resistors with them. Diagnosis was easy with the smells and burned resistors giving clues. It is a personal pleasure to keep this old set running.
Neil
Contact your nearest fcc office and report your refrigerator. The fact that it is "smart" does not excuse it from causing interference. Have a copy of the part 15 rules ready and point out the parts that you, as a citizen, believe are being violated.
Of course "Must accept interference" may collide with "Can not cause interference."
If a neighbor has a similar refrigerator and his kitchen is close to yours, you might start getting his readings influencing your refrigerator. You might have more milk than you have.
When we open our refrigerator the TV turns on/off. The TV remote is IR. Not sure what the connection is there.
Modern problems...
I want to ask you some questions.
And I will, later tonight, after
I get back.
Going out the front door right now...
Byyyyyyyyeeee!
Bruce, DRS2
It took me longer to get back here than
I thought.
I was wondering, when or where did you
get your Superpro, how long have you had
it, which is sort of the same question, and;
What do you tend to use it for - in other
words, where in the spectrum do you like
to listen - or is it just all over the place...
Do you even have time to use it? How much
does it weigh, how clean is the audio?
Is there anything peculiar about your particular
unit?
And because it was a military receiver, did it
originally run on a different voltage? (I guess
the answer is probably no.)
I believe some of these radios went up to
40 MHz. Does yours tune that high?
I ask all of these questions because I have a
Hammarlund HQ-140X, which is a distant
cousin, and I love the HQ-140X. It's not as
good as a Superpro, but it isn't bad. I think
my HQ-140X is from 1954, so it's about 58
years old. It still works great!
Best Wishes,
Bruce, DRS2
Bruce, my history with this goes back a ways and I am glad you are interested.
I obtained the radio when I was in graduate school in engineering. Being a G. A. I was part of the squad used for grunt work when needed and was asked to help clean out the college ham radio shack. This was literally a shack on the roof of the EE building but the ham club was not active and the space was needed for office use. The Dept. Head told me to trash the radio and I asked if I could take it home with me. He said essentially to just get it out of there so I backed my '63 Chev to the loading dock and away I went. This was in 1968. The radio has a date stamped inside the front panel that it was fungus proofed in 1943 so I figure that was the date of mfg.
The package consisted of the receiver, power supply, a wooden 19" cabinet for the receiver, and a metal 3 foot high 19" rack mount cabinet which housed the power supply. I have since replaced the wood cabinet with a metal one. The receiver is spec'd. to weigh 70 lbs. and the power supply around 35 pounds. With the metal cabinets the whole thing weighs about 180 lbs.
The power supply is operated from the 120 VAC line but the radio can also be operated from batteries.
At the time I was newly married and we lived in a two bedroom apartment. One of the bedrooms was my study area with a desk and the radio was placed next to the desk on top of the power supply cabinet. I had an old 12" speaker from a junked TV connected to the audio output. Mainly I listened to broadcast AM with it but it was fun to sometimes tune in Radio Habana from the Peoples' Democratic Republic of Cuba and listen to the anti US propaganda. I was able to receive the BBC world service, VOA, and other shortwave programming but mostly listened to local AM. The radio covers from 550 kHz to 20 MHz. Throughout various moves it has always been in my work area.
It is placed here in my basement in my "lab" and I use it now mainly to listen to my part 15 AM signal. I am using a shelf hi-fi speaker with it and the audio is very clean and it has enough power to drive one out of the room. The IF bandwidth is adjustable from 3 to 16 khz and when set wide open and tuned to my AM tx. the sound quality is excellent. There is a marked difference in the audio quality of my signal compared to commercial stations.
Almost any piece of wire can be used for an antenna but I have found that a small loop antenna is best for rejecting power line interference so this is what I use as the antenna.
The only unique feature is the front panel. It was in very poor shape when I got it so I removed the panel, stripped and cleaned it, and painted it with flat gray auto primer. The markings are embossed into the panel so I used a Rapidograph pen to ink the white lettering and it turned out looking very nice. Some may say this reduces the antique value but I would rather have a nice looking radio than a grubby looking thing. I don't care about the value since I don't intend to sell it so the value is meaningless.
From my readings the original price of these was about $565 in the War years which is equivalent to approx. $6000 today so there weren't too many in private hands.
It is nice to be able to share this history with someone who is interested so thanks for asking.
Neil
I would say the fungus proofing worked, or you would have mentioned it.
The radio was made priceless and invaluable by your careful re-design of the front panel, unless the word "invaluable" means something other than I intended.
Radio equipment on life support gives hope for the survival of humanity.
Neil, this is great info about
your radio. I may have some
other questions if I can think
of them. I am really interested
in this stuff.
I have several old tube radios. My
HQ-140X is the second one that I
own. The first one was lent out and
didn't come back, but looking back
on it, I believe there was a true
misunderstanding between my friend
and I on how long he could keep the
radio. That's a long story.
The HQ-140X was made between 1953 and
1956. I have reason to believe the one
I own now is older than the original one
I had from 1974 to about 1984.
My original HQ-140X had a lit square orange
signal strength meter. The HQ-140X I have now
has a round signal strength meter that is
not illuminated. I'll have to look at my notes
but I think they made the change around 1954. So
my radio is from 1953 or 1954. My original
HQ-140X - then - was from later on, or about 1954 to
1956.
I think this was Hammarlund's last single conversion
general coverage radio. Maybe.
I'll have to look into it a little more.
About 30 years ago, I had another friend
who sold every piece of radio gear he had
so he could get a SuperPro.
I love the fact that you have one and that it
is still alive. What a great radio!
You must have a good sturdy table.
There may be some more to this conversation!
Thank you for the story.
Bruce, DRS2
Bruce,
It is interesting to try to nail the date of old radios. Sometimes the tubes are marked or the electrolytics are marked but this isn't very reliable.
I like the signal strength meter and I assume the one on your radio is similar. Here's a shot of the radio in operation:
The top of the case is not bowed as it appears in the pic...this was due to the macro lens on the camera. The dials and signal meter plastic has yellowed but with the incandescent back lighting it is a very warm yellow/orange glow. By the way, the lamps used in these old radios are getting a bit hard to find. Used to be any decent hardware store had them but no more around here.
And another showing the power supply:
The radio rests on the power supply rack cabinet and I added casters to the bottom so I can move it. Before this I had to use a hand truck. Sorry the pic is a bit over exposed but you get the idea. Note the yellow hue on the power supply panel. This was not refinished and it is the color that the radio panel had before I refinished it. The yellow may be due to the fungus proofing or maybe just old age.
That's the update for now.
Neil
Wow!
Impressive pictures! What a treat!
One of the problems I have here is
that I have tried to keep a low
profile set-up in a small area of
the house.
That is hard when you are trying
to have a ham radio station, a Part
15 station, a DX listening post and
a collection of several antique AM
radios. One big shelf on one side of
one room would probably do. But I
haven't figured out how to do that
yet. To make things more complicated,
I have some ham QRP equipment and a
vintage ham station. Oh, crud - I have
some crystal sets, too.
The idea would be to make it look nice,
almost like a little museum.
This is the thing, over a 40 year period,
with intermittent blindness from detached
retinas and their complications, people have
just given me radios and audio equipment
from broadcast stations. I know a lot of
radio people, and have been extremely
fortunate. Generally, I will get some gear
from the attic, use it for a while, and
then put it back, and bring out something
else.
Oh no, duty calls!
I'll be back as soon as I can.
Bruce, DOGRADIO STUDIO 2
Listening to a part 15 radio station on a radio of such major serious proportions is similar to the an elephant being entertained by a peanut.
It is an impressive thing.
There are two great things
happening there. One is that
that radio is still in one
piece and running.
The other great thing is that
Neil is there to keep it that way.
And it is a beautiful piece of gear!
Best Wishes,
Bruce, DRS2
"And it is a beautiful piece of gear!"
Seeing that radio reminds me when I was listening to ham communications in my grandfather's shack at the grumpy young age of 4.
But I think it was my grandfather who got grumpy when I would sneak up and turn one of those large magical knobs making the sound in his headphones go nuts!
I would scurry away laughing every time. It was always funny to me because he never knew I was there ready to twist and turn and then run and burn! 😀
RFB
RFB, Nice story. My grand-daughter does this to my son's test equipment on his bench. Payback is great!
Neil
Having brought up two kids,
that sounds just about right!
Bruce, DRS2