As we are moving out, most of my really
good stuff has gone to my trusty Brother's House.
Such as the wonderful AMT-3000.
So what's left here?
In the junk pile there was a Ramsey AM-1 that
didn't work.
Before you laugh too hard, I will mention that
this transmitter was modified, and I was able
to get it to go 1/3 to 1/2 mile away from the house.
I don't remember the actual distance, but it was
pretty good for a transmitter of this kind.
A stock AM-1 will FM like crazy, or at least mine did.
Still, for yardcasting it was OK even with the FMing.
Later, I built an oscillator from the Medium Wave Alliance
website (remember them?) the crystal controlled kind.
I took the VFO LC out of the AM-1 and fed the crystal osc.
into that point.
It worked. Now there was no FMing anymore.
The transmitter required some EQ, and I did that.
I also built some huge loading coils on buckets from
the hardware store - I even made a variometer.
(This is a big coil that rotates inside an even bigger
coil - you rotate the smaller of the two - and you can
tune the thing - the coils are hooked together in series.)
Anyway - until I got the SS-Tran AMT-3000, the AM-1 was
tons of fun.
So just this night I found it in pieces in a pile.
The crystal osc. had been ripped off, a choke was
halfway off the board, some wires were broken -
there was no case, and no power indicator light.
(I had a nice yellow one.)
Anyway - I patched it together and put in 9 volts.
(It might really need 12 - I don't remember.)
I hooked up an IPOD which was playing "Hey There,"
by Sammy Davis Jr. (1954?) and it came though the
radio. It sounded very good. "Though she won't
throw a crumb to you... you think someday she'll
come to you........."
I ran about half the song through in the test, and I
was quite satisfied. No transmitting antenna has been
put on yet. (Another homemade tunable loading coil would be
required.)
So there's another Part 15 rig working.
I thought the crystal was on 1700 kHz, but
it turns out it is really on 1670. I'm glad the
1670 rock survived the junk pile existance.
Crystals from 1590 and 1700 have been lost.
Oh well.
There is a weak highway TIS station on 1670,
but if my signal doesn't leave the house, it
doesn't matter.
These crystals are very expensive, but I think there
are 1650 rocks on the net for very very little money.
1650 must be a common crystal needed for present
day technology. (Am I right?)
It was really fun getting this old thing going.
It was all I had 8 or 9 years ago.
Best Wishes To All,
Brooce, WLP
If you're still reading this - I believe the
output impedance of the AM-1 is about
the same as it's big brother, the AM-25.
20 or 25 ohms, something like that.
Well, it's fun anyway.
Additionally, I just remembered that some
people have put the osc. crystal in place of
the LC - in other words they did not go to
the trouble of building a new osc. circuit.
They just plunked the crystal into the place
where the LC was before. (????)
Some people have also radically changed the
output "tank," but maybe that's going too far.
It's sort of like putting air conditioning on a
skateboard.
Brooce, WLP
Do you have a sensitive AM radio on your skateboard?
I actually do have a skateboard, from 1965,
right around the time when skateboards started.
My dad found the best and most costly skateboard
in the stores. It is called (because it's still here) a
HotDog. It's a little messed up, but if I wanted to, I
could fix it. Many of the kids had skateboards that
were called, "Fifteen Toes," - I am sure there are
skateboard websites - now I want to go to one.
Anyway - what does this have to do with radio?
Well, I can stretch the connection......
So, a couple of years ago, I had 2 jobs (wow) - -
one of them was at the local "Stop And Shop," part of a
supermarket chain. I bagged groceries (sp?) for hours
and hours, yeah. Then I went to my other job, at the
University of Hartford. BUT the supermarket job was quite
physically demanding. Somewhere around that time -
a skateboard appeared at our house - apparently it was
not wanted - or misplaced - or something.
I was pretty pleased with myself about all of the
physical work I was outputing. (I became quite
humbled later on.) I had been moving things,
shoveling snow in the wintertime, moving shopping
carts (during times when my vision permitted, another story) -
yeah - stuff like that there.
So one day after a lot of activity at the store -
I found the skateboard and took it to my other
job - at the University Of Hartford.
What does this have to do with radio? We are
getting closer.
I tried to skateboard outside the administration
building, and even in the office itself. I had some
sucess, and was - again - very pleased with myself.
I found that a really low center of gravity was the key.
If I kneeled down far enough - I could get that center
of gravity.
Alas and alak (???) my back problems flared up.
The dreaded sciatica returned. At age 58 I was
grounded (and I don't mean electrical ground either.)
What does this have to do with radio?
If I was skateboarding now - my skateboard radio
of choice would be - - my almost destroyed
Sony SW-20 - a teeny multiband analog
pocket sized AMFM/SW portable. One of the best AM
radios I have - the FM sort of works - the SW
bands don't - but the AM BCB is as sharp as
nails. Heck, I heard West Duetcher Rundfunk
(sp) in Langenberg (sp) Germany on that radio
on 1593 kHz years ago in Connecticut. Q5 guys.
I would take THAT RADIO on my skateboard if
I could skateboard, yeah, er, ahem.
OR...... what about Part 15????? Just tape
an MP3 player and a C Crane underneath -
and blamo - skateboard Part 15 radio station.
Just skateboard QUICKLY around the neighborhood
and you will have a really good coverage area!
All the best of whatever there is:
Brooce, WLP
P.S. The Sony SW-20 is very small
and very good on the Am band. Several
years ago - a new kind of AM dxing came
about. Because of awsome technology -
currently manufactured AM radios became
incredible DX machines - hence - the: Ultralight
DX radio movement! Now AM DXers stand out
in fields and swamps and by the ocean with awsomely
powerful AM DX radios that are so small they can be
lost in the outgoing camping garbage.
One such radio is the Sony SRF-59. A teeny analog
AM/FM "walkman" type unit - with it's 55 kHz IF -
WOW - can you get any better selectivity than that?
And for 15 to 20 dollars!
BUT alas and alak (???????) it has been discontinued
by SONY. I wanted one but they don't make them
anymore. Does anybody know about a currently
manufactured radio that is you know - - "the same?"
Let me know if you do.
Thanks again- - - -
Bruce I enjoy the way you skated radio into that story.
In the pre-skateboard years we had what were essentially elevated skateboards with a pulling handle known as "Radio Flyer" wagons.
Our Crosley Floor Model Radio was clearly too large to transport on the wagon, and the center of gravity would have been too high to stand up while riding.
I have always admired the skill of well-packing a grocery bag, and perhaps it could be turned into a TV competition to see who could get the most produce into a single back.
The Crosley Upright Cabinet was converted into a Catholic Cathedral in 1964.
I looked up the reveiws for that Sony Walkman radio. All I can say it that the reviews were good. One could potentially plug it into an amplified speaker system and have great AM (And possibly FM) at a cheap price. Granted not Stereo, but for DXing and tuning in your AM part 15 transmitters it could be a big help. The review did say that the dial was small and took some skill to fine tune the DX stations on AM however. Still looking at a Tecsun Radio with a meter when the time comes for me to get the Talking House AM Transmitter. Now if the AM petition ever passed about no limit on antenna length I'd simply connect 80-10 Ft of wire and have a ball with it. But we'll see how that one goes.
Living inside an RF environment is a constant struggle between organization and unworldly mystery.
It all began in 1954 with a Knight Kit Phono Oscillator.
Skip ahead about a hundred years to the present, and we have an AMT3000 over there under the lower corner of that desk which has been off the air for awhile so I could replace the audio line which seemed to be acting strange. The level would change at times, as if one of the connectors might need cleaning, but that didn't help.
The triangular loading coil between that transmitter and the metal window frame is one of my proud achievements, which is why I mention it now.
So, that original audio cable was actually a video cable carrying only half of the stereo audio to the transmitter, so I replaced it last night with a new 25' stereo cable and guess what - when I went on the air at 1550 kHz the audio level kept changing, but only when I moved around. It was an RF problem of some kind.
The spectrum analyzer showed something really strange... the mountain-shaped RF signal had lines rippling through it like you'd see with an audio tone, but I wasn't feeding a tone. Even more odd, there were humps on both sides of the carrier, suggesting that I might have IBOC (HD digital) channels.
Turning the audio input to the AMT3000 off the peculiar artifacts disappeared, indicating that the audio line was acting goofy. Maybe a 25' unbalanced stereo pair is not the way to go. Time to think about putting in transformers and going balanced.
That's just one story here in the RF bath. Earlier in the day I noticed weird things with the two C.Crane FM Transmitters which rendered earlier claims about perfection not only null but void along with it.
Meanwhile the audience, a proven figment of imagination, is out there wondering what is happening at KDX Worldround Radio? Obviously then I can't consult them for help.
When you come right down to it, which transmitter actually does get better range?
there were humps on both sides of the carrier, suggesting that I might have IBOC (HD digital) channels.
The humps might result from insufficient shielding of your audio source/cables -- which is adding external signals to your program audio.
That makes the best sense I can think of too...
Here's a new finding... at the far end away from the transmitter if I unplug the 25' audio cable from the computer's audio-out the oscillation stops and the audio cable does not cause a disturbance to the transmitter.
It seems the connection to the computer is setting up some kind of... what could we say... a circuit that oscillates?
Looking back at the previous setup, the video cable used as an audio cable was indeed better shielded than the consumer grade audio cable now in use, but there was some smaller evidence of RF interference in the audio system.
Time to build balanced audio lines.
Going over the 1550 installation in the light of day I found the cause of my peculiar oscillation problem.
Transmitter RF antenna output was attached to ground, and the transmitter RF ground was attached to the antenna.
I swapped the clip leads and all is well.
At this pace I'll get smart by perhaps 3067.