How impressive!
I don't even know what to say.
What a fantastic piece of work.
And you were still in high school
doing all of that? The thing that
would have stopped me cold would
be the 900 volt supply.
I have often thought that some kind
of IR link STL - laser or bright LED
would be a really cool idea for a
Part 15 station. Just to say that
the program was going from the house
to the back yard transmitter via that
kind of link would make it all worth it.
Even a visible laser - which would probably
only work at night - would be cool. Then you
could see the actual laser beam hitting the
receiver sensor.
That's got to be one of the most unique stories
we've ever had on the board here!
Bruce, Dog Radio Studio 2
Yes, Neil, that is a tremendous project coming from your creative imagination at that time.
What kind of bandwidth do you think could be carved out of a UV beam?
Am guessing that the beam is interrupted by a physical obstacle, maybe a passing person, animal or bird. But that may also be true of other point-to-point signals as well, if I'm not wrong.
Heck, it would be fun having our audio pass through a UV beam even to cross the room, simply because it would be something to admire.
I'm wondering how difficult it would be to modify, say, an SSTRAN to work in the Part 15 longwave band. Not being an electronics designer and primarily a user, I recognize that this may be a very stupid question.
"I'm wondering how difficult it would be to modify, say, an SSTRAN to work in the Part 15 longwave band."
Probably not easily.
You can build or purchase a unit specifically designed for the LW band and run 1 watt.
I suggest taking a look at the AM-88 unit or the LF90.
http://northcountryradio.com/Kitpages/lf90.htm
http://northcountryradio.com/Kitpages/am88.htm
RFB
What kind of bandwidth do you think could be carved out of a UV beam?
Limiting this answer to the use of components inexpensively and readily available to hobbyists I would estimate a bandwidth of 20 to 30 kHz for an optical link. I chose UV for my project so it could operate in the presence of ambient light which has relatively low UV. Otherwise there was nothing special about using UV for this.
There is a trade-off between bandwidth and receiver sensitivity. I worked on a high speed sensing system where we had to use phototransistors for the detector and 30 kHz was the max frequency that we could use. Use of photo diodes gave higher frequency but the sensitivity was not adequate. This project was constrained by cost and 30 kHz was adequate.
An IR laser could be used but solid state lasers require current control circuitry and present a possible danger with the concentrated beam.
For someone who wants to home brew a link I suggest using IR or visible LEDs and phototransistors. With proper focusing a hundred foot range should obtainable.
Neil
The guys at North Country Radio
have good stuff. One of my FM
transmitters is their MPX-96.
I think the LF-90 is just a morse
code transmitter, but I could be
wrong. The AM-88 runs on the AM
and LW broadcast bands with amplitude
modulation. I'm not sure about the
power, though.
Heck, as a ham, I would get an LF-90
just for experimenting with Morse code.
But that's just me.
Bruce,
Dog Radio Studio 2
A group of low power radio experimentors called "part 15ers" have invented a small device which, when aimed at the sun, allows audio modulating sunlight in such a way that radio programs can be heard everywhere there is daylight, using inexpensive light-band radios.
The inventors became instant billionaires and quickly purchased NBC, CBS and Fox.
The old fashioned AM and FM bands were closed and the FCC re-assigned to motor vehicle regulation.
RFBurns, a spokesman, explained the small light emitting transmitter is floating in a backyard kiddie-pool somewhere in Wyoming.
Radio8Z, from Ohio, explained that the device uses "regular parts."
Dog Radio Studio 2 from Connecticut says they are working on a night transmitter that will modulate darkness.
"I think the LF-90 is just a morse
code transmitter"
A CW unit which would be very easy to adapt for AM with either a low level balanced modulator or high level modulation at the final.
RFB
Tonight I visited the long wave band, first on the Sangeon ATS-505 and then on the Zenith Transoceanic.
The Sangeon covers 153 to 279kHz, with a total of 16 distinct channels.
The Zenith is a continuous dial from 150 to 400kHz.
At this time there was nothing to hear whatsoever, except some buzzes and statics.
Oh good, our 171 and 180 frequencies come in on both radios. That is not true with 13,560mHz, since the Zenith has a gap right at that part.
It will be swell to hear the station down there. In fact, the poor band needs the renewed activity.
Thanks for the info about modulating
the LF-90 RFB.
Carl, your light-band comment was hilarious.
By the way, it is just as hard to listen to
LF is it is to transmit, in my opinion.
The only reason I can hear these Long Wave BC
stations from Europe is because I'm on the east
coast. Carl, I think you are too far away.
However, you should hear a bunch of navigational
beacons, although, I'm not sure the coverage of
your radios, and a BFO might help.
I have some other Long Wave trivia coming.
Bruce, Dog Radio 2
Bruce, I have always had the feeling I was too far away.
There are tons of examples of IR wireless devices. Everything from RC models to cordless audio headphones to remote controls to alarm systems and much much more.
Try a long wire antenna Carl. I am further west from the east coast and I can pick up a few of those European LW stations during the pre sunrise hours and post sunset hours.
They are noisy as all get out but there nonetheless. Ironically the range of 150Khz to 175Khz here is incredibly quiet of buzz and static. Above 175 and it becomes saturated with noises.
RFB
Carl: You mentioned that you were
always too far away.
It reminds me of one of my good friends
who always said to me, "Bruce, you are always
getting closer and closer to the farther
away!"
RFB, I am very curious what your long wave
receiving set-up is. How long is your long
wire and what kind of receiver are you using?
Also, I can't remember what state you are in,
even though you mentioned it on "The Low Power
Hour(s)," and probably on this board a bunch of
times.
I have an old Icom R-70A receiver that does
pretty well down there. My Sony ICF-2010 works
down there, too - but the old ten dollar boat
radio really cooks for the LWBC band.
I have a few more comments - be right back!
Bruce, Dog Radio Studio 2
"I'll get with my host and see what kind of deal I can get."
For the FTP part, that is available right now. I have unlimited storage space and unlimited bandwidth usage on my host provider.
In fact most of the programs that air on my station are uploaded to my FTP and those program files are very large HQ files.
Setting up a folder for this venture will take all but 1 minute and be online immediately.
One hurdle navigated....on to the next.
RFB
For transmission a vertical seems like the way to go, but 50-feet is high for the ordinary person (the LW tower). Yet, I have a great supply of long bamboo poles, from my bamboo forest. They are about 25-feet or longer, and very hard, although they do bend like fishing poles and snap back in place. It just might be doable with good bracing.
There is a spot being cleared up the hill in back for an outdoor mast, at least for .... maybe the 17-foot SW vertical AND a 10-foot medium wave stacked in-line, for a total of 27-feet....maybe I should go out there now. No, it's the midnight hour, flashlight activity might look strange in the darkened neighborhood. I could start digging the ground rod spot using a minor's hat...
Awaiting instructions on uploading and downloading from the FTP.