A little off topic but with regard to the Armstrong Commemerative Broadcast, I have a recording of the program broadcast a few years ago.
The broadcast was simulcast on the original frequency with a special authorization license and the web. My recording was off the web.
The program was quite long so I broke it into a few files to keep the files smaller.
I'm sure it was probably copyrighted so no one would want a copy to air (wink-wink-nod-nod).
A little off topic but with regard to the Armstrong Commemerative Broadcast, I have a recording of the program broadcast a few years ago.
The broadcast was simulcast on the original frequency with a special authorization license and the web. My recording was off the web.
The program was quite long so I broke it into a few files to keep the files smaller.
I'm sure it was probably copyrighted so no one would want a copy to air (wink-wink-nod-nod).
Hi MRAM! Armstrong is a personal hero of mine, too.
I'm sure you and a lot of other people on this board
have seen the incredible documentary, "Empire Of The Air."
It's a real shame that Armstrong did not live to see
FM radio really flourish!
Best Wishes
Bruce, MICRO1690/1700
P.S. My brother is a broadcast historian and
heard that broadcast from five years ago.
I believe it was also broadcast from WFUV, 90.7,
Fortham (Sp?) University, New York.
Hi MRAM! Armstrong is a personal hero of mine, too.
I'm sure you and a lot of other people on this board
have seen the incredible documentary, "Empire Of The Air."
It's a real shame that Armstrong did not live to see
FM radio really flourish!
Best Wishes
Bruce, MICRO1690/1700
P.S. My brother is a broadcast historian and
heard that broadcast from five years ago.
I believe it was also broadcast from WFUV, 90.7,
Fortham (Sp?) University, New York.
Upon reading the comments about the commemorative broadcast I checked archive.org and found the 70th Anniversary program available as "community audio."
http://www.archive.org/details/armstrong-commemorative-broadcast
Upon reading the comments about the commemorative broadcast I checked archive.org and found the 70th Anniversary program available as "community audio."
http://www.archive.org/details/armstrong-commemorative-broadcast
Thanks for that, Carl.
That's good to know.
Bruce, MICRO1690/1700
Thanks for that, Carl.
That's good to know.
Bruce, MICRO1690/1700
I found the second 49 MHz walkie talkie. I wired
my station audio processor output directly into the
circuit board of the first 49 MHz unit and shorted out
the transmit switch so it would always stay in transmit
mode.
Then I wired directly into the board of the second 49 MHz
unit that will be used as the receiver.
I turned my audio board and audio processor, and put a record
on the turntable. Then I was running audio into the
49 MHz transmitter. Then I brought audio out of the
49 MHz receiving unit and fed it to my C Crane transmitter,
which has been modified for mono and is transmitting on
88.3 MHz.
Listening to the FM radio on 88.3 - well - it sounded pretty good.
The fidelity was acceptable.
(In other words, the music had highs and lows, it
didn't sound like a telephone.) Both 49 MHz units and the
C Crane are running on batteries right now.
Right now there are no antennas on the 49 MHz transmitter
or receiver. The units are about 15 feet apart and there
is no noise, just a little hum because the 49 MHz units are
not in shielded boxes.
I bought some diodes to isolate the solar cells because they
will be in parallel with each other. Running the C Crane will
be no problem in sunlight (I think) as I was able to run it under
a light bulb (well, almost touching the bulb). Although I haven't
measured the current the C Crane needs, I don't think it is much.
I need a few more solar cells to power the 49 MHz receiver.
Right now my local Radio Shack
doesn't have any, but I will get more when they are in stock.
Again - the solar cells that were given to me are the same as
the ones obtainable at Radio Shack. Each one is 6 volts at
50 mA.
So I have almost all of the pieces for a remote 49 MHz receiver
and Part 15 FM repeater that will run off of sunlight. No attempts
will be made to charge batteries at this point of the experiment.
And as mentioned before, I want to get onto a 49 MHz link frequency that is
in between the baby monitor channels.
So far so good.
Best Wishes
Bruce, MICRO1690/1700
I found the second 49 MHz walkie talkie. I wired
my station audio processor output directly into the
circuit board of the first 49 MHz unit and shorted out
the transmit switch so it would always stay in transmit
mode.
Then I wired directly into the board of the second 49 MHz
unit that will be used as the receiver.
I turned my audio board and audio processor, and put a record
on the turntable. Then I was running audio into the
49 MHz transmitter. Then I brought audio out of the
49 MHz receiving unit and fed it to my C Crane transmitter,
which has been modified for mono and is transmitting on
88.3 MHz.
Listening to the FM radio on 88.3 - well - it sounded pretty good.
The fidelity was acceptable.
(In other words, the music had highs and lows, it
didn't sound like a telephone.) Both 49 MHz units and the
C Crane are running on batteries right now.
Right now there are no antennas on the 49 MHz transmitter
or receiver. The units are about 15 feet apart and there
is no noise, just a little hum because the 49 MHz units are
not in shielded boxes.
I bought some diodes to isolate the solar cells because they
will be in parallel with each other. Running the C Crane will
be no problem in sunlight (I think) as I was able to run it under
a light bulb (well, almost touching the bulb). Although I haven't
measured the current the C Crane needs, I don't think it is much.
I need a few more solar cells to power the 49 MHz receiver.
Right now my local Radio Shack
doesn't have any, but I will get more when they are in stock.
Again - the solar cells that were given to me are the same as
the ones obtainable at Radio Shack. Each one is 6 volts at
50 mA.
So I have almost all of the pieces for a remote 49 MHz receiver
and Part 15 FM repeater that will run off of sunlight. No attempts
will be made to charge batteries at this point of the experiment.
And as mentioned before, I want to get onto a 49 MHz link frequency that is
in between the baby monitor channels.
So far so good.
Best Wishes
Bruce, MICRO1690/1700
Would you get better sound outcomes with the audio processing after the receive walkie? That way you could re-curve the audio after the audio had gone through the STL...
kewl work, all the way around
Would you get better sound outcomes with the audio processing after the receive walkie? That way you could re-curve the audio after the audio had gone through the STL...
kewl work, all the way around
If your 49mHz system doesn't have pre-emphasis you might consider adding it to the transmitter and de-emphasizing either in the receiver or after the receiver.
If your 49mHz system doesn't have pre-emphasis you might consider adding it to the transmitter and de-emphasizing either in the receiver or after the receiver.
The really weird thing is that the audio
sounds quite good, although I will
remember both of your suggestions.
Just to test the range of the 49.83 MHz
transmitter, I hung a little two foot transmitting
antenna off of the RF out. I went down the
street with an ICOM R2 scanning receiver.
The transmitter is on the first floor of my house.
The range was at least 500 feet, but then I
started to hear interference from another signal.
Having no desire to listen to this signal, I turned
around and walked back home.
A lot of people have said that the 49 MHz range
is pretty devoid of baby monitors, but I think there
still might be quite a few around.
My main objective is to get an FM solar powered repeater
running. I would like to get these units between
the 49.83 and 49.845 channels. There might be some
way to shift the frequencies slightly with some small caps
in parallel or series with the crystals. If not, I can do
the math and put in some other crystals. Still, I don't
know if 7.5 kHz away will really make a difference as far
as interference is concerned. And if 49 MHz isn't practical,
there are other Part 15 frequencies that can be tried.
Well, anyway, the next step is to get the thing outside
in a package and put it in the sun and see how much
sun it needs to repeat the signals. I have to get some
more solar cells first.
So thanks again SWCIS and Carl. I will keep you guys
posted.
Best Wishes
Bruce, MICRO1690/1700