[Lf] [Fwd: LF: TV on longwave!]

[Andre Kesteloot]

Les Rayburn wrote:

> Pleased to report that yesterday afternoon I was able to transmit narrow band
> TV signals on 174khz. Using an old Palomar Engineering transmitter in AM
> mode, and the software designed by Con, ZL2AFP, I was able to successfully
> transmit and receive these signals out to a range of about 1/2 mile.
>
> Initially, I had used the Palomar Transmitter and fed it into my existing
> lowfer
> antenna system...but has both Lyle and Stewart had predicted, it's high "Q"
> design proved to be unsuitable for AM transmission. I then jury rigged
> an older coil that I had ( Q=200) and tuned the system to resonance
> with it. Using this less efficient tuning arrangement, I was able to
> successfully receive my transmissions inside the shack at a distance
> of about 40 feet.
>
> After making some adjustments to the software...I used my Icom 746 has
> a mobile receiver in the car. This system uses a mag mounted version
> of the LF Engineering active whip has an antenna. I took along a tape
> recorder, has my laptop was at work.
>
> Using this system, I drove around the neighborhood and recorded the
> narrowband television signal from the shack. I had focused a small
> b&w camera on a test card reading "XM" for the test.
>
> I took careful notes of my location, and drove a little further away
> every 10 minutes or so. After returning to the shack and playing
> the tape back into the soundcard, I discovered that copy was
> maintained out to about 1/2 mile.
>
> The range was not very impressive but has expected. LF proves to
> be a lousy place for a high bandwidth mode like AM. In addition,
> the summer time static levels and low power (1 Watt) will
> really limit the range.
>
> However, it did prove that narrowband television on longwave is
> possible and it was a heck of a lot of fun!
>
> I plan to test this software on 2 meters when I return from my
> business trip, expecting much better results there. Look for an
> article complete with photos and the newest software from
> ZL2AFP on the Noise Floor site soon. Hopefully others will
> experiment with this mode on both LF, HF, and VHF.
>
> I think on the amateur bands this mode could provide
> a very useful "DX mode" for ATV, though some would
> debate wether it was ATV at all. It does provide a nice
> 3-4fps live video signal in a very limited bandwidth, and
> has already been proven on 20 Meters in limited tests.
>
> In my book, that means it's not slow scan TV, not
> digital TV, but still TV. I encourage hams to experiment
> with narrowband television...
>
> 73,
>
> Les
>
> Les Rayburn, N1LF
> 4919 Cox Cove
> Helena, AL 35080
> XMGR 184.8988khz WOLF Mode
> 1LF 187.300khz
>
> Looking for a challenge? Try the ultimate weak signal mode, on 1750 Meters!
> Visit the Noise Floor!
> http://www.highnoonfilm.com/xmgr