It's been up before but not recently. It's a lot
of fun to read.
I think in order to do this one would have to
have A LOT of real engineering experience.
It worked for the author. But would it work
again for another person? We don't know.
As far as I can tell nobody else has tried it.
And even if it worked, would you want to
leave it running while you went to the store
for a carton of orange juice? We don't know
that either.
I don't have an AM-25, but I would love to have
one. As many of us know - the AM-25 needs mods before it really
runs right. But then it does a good job, I hear.
So first you have to get an AM-25 and get it running right. Then
you have to do the power mods. And then you have to rig it
for carrier current, which has REAL dangers - that's just the
way it is.
I have built some homemade couplers and I finally got one
to work correctly. It's not easy. I developed a HUGE respect
for the AC line (and what it takes to safely put an AM radio
signal into the line.)
If a bunch of people were able to do this project - brainstorm
it - and get it to where everybody agreed it was safe and stable
that would be great. As of now that hasn't happened.
I do love reading the article and reading it again every once
in a while.
But running all of that RF power through that little
transmitter leaves me with many questions.
Bruce
P.S. (This was added a little bit later.) I just
read the article again. It really is a fun read.
But my other opinions are still the same.
I have a Ramsey AM25B awaiting the Radio8Z mods previously posted by Niel for improving the Part15 radiant antenna compliance.
Since I also have two LPB couplers and a Radio Systems coupler I think I could safely try the CC mod, but I may never do it because...
I have two LPB transmitters awaiting service, and only plan to have one CC channel.
But along with Bruce I say it is sure interesting.
I didn't know you had an AM-25B.
Maybe you could do a Low Power Hour
about it someday. Well anyway - keep us
posted on how the work on that transmitter
is going. I know Neil has done a great deal
with it. I'll have to look that up.
Bruce
Good idea, Bruce, a little segment about the AM25B.
I spent a lot of time with it when it was built from the kit.
The tech at Ramsey was great, he got on the phone and talked about every question I had and was totally up front.
I went wild thinking the circuit board was loaded with ground loops and actually started hacking the board to reduce a few loops... which actually reduced the hum...
But the main fix was using a different power supply. The one they sent was not well matched and caused an AC buzz.
I changed the audio modulation transformer by using a Nortronics tape bias transformer, which seemed to give better modulation, but I did not verify that scientifically.
Coming soon.
I heard on one of your shows somewhere
that you BUILT a tape recorder.
Next time you get over to the "old radio" thread
or even on another Low Power Hour, you might
want to talk about the AM transmitter you
built on a metal shelf with the vacuum tubes
and such. I'd love to hear about that one too.
Bruce
To have honest banking practices here on the website I must say that I didn't totally build a tape recorder, unless I did so and forgot.
But I did seriously modify two tape recorders.
I had a Wollensak which ran at 3 3/4 and 7.5 ips half-track mono.
With the help of a buddy who machined a capstan I put in a fat capstan which provided 7.5 & 15 ips (inches per second).
A 7" reel of tape running at 15 ips lasts 15-minutes.
Another friend contributed an Ampex direct-drive capstan motor so I took my Roberts Tape Recorder, wrenched out the faulty rubber pulley method of spinning the capstan, and put that Ampex motor in there and also had 7.5 and 15 ips.
The original Roberts motor continued to handle the supply reels.
Maybe that's the machine you remember me talking about. The electronics were very sloppily built so I unsoldered everything and replaced all the components with better caps and resistors.
The Roberts is still down in the basement. Maybe I should do something.
Tomorrow.
That AM transmitter installed into a metal shelving unit was a beast. Lucky I don't have it now, I might start a life as a pirate broadcaster and have visitors.