[sci.electronics] Low-power TV transmission

jbn@glacier.STANFORD.EDU (John B. Nagle) (05/25/88)

     Any info about the following company, and their TV units?

	P.C. Electronics
	2522 S. Paxson Ln.
	Arcadia  CA  91006
	(818) 447 4565

	TXA5-33 transmitter (1w, 900MHz)
	FMA-5 subcarrier generator
	TVCX-33 receiver 
	VRC45 subcarrier demodulator

This is for a very short range research application, to be licensed under
Part 5 (Experimental) not ham.  Advice on suitable alternative hardware
would be appreciated.  The goal is good-quality color TV transmission
over a few hundred feet.

					John Nagle

brian@ucsd.EDU (Brian Kantor) (05/27/88)

In article <17464@glacier.STANFORD.EDU> (John B. Nagle) writes:
>     Any info about the following company, and their TV units?
>
>	P.C. Electronics
>	2522 S. Paxson Ln.
>	Arcadia  CA  91006
>	(818) 447 4565

When I called them they seemed to be a bunch of weird people.

Besides the "please wait while we look you up in the Callbook
to see if you're really a ham", they also INSISTED that I contact
a local ATVer before I order anything from them so that I'd be sure
to understand all about ham TV.

From this attitude I come to the conclusions:
	1. They're really not very interested in getting new people
	into the hobby.
	2. They're really not very interested in selling their stuff.
	3. I'll just have to wait a few years until the old farts with 
	this kind of attitude problem die off and do ham TV when I'm welcome.

If the people who developed and promoted packet radio treated people
this way, just how popular would packet be today?  Of course, packet was
a new technology, and ham TV isn't new at all, but I'm sure not
interested in ATV anything like I was before I called them.

Or maybe it was just a real bad day in Arcadia?

Why do you suppose they bother to advertise?  

	Brian Kantor	WB6CYT	UC San Diego   brian@ucsd.edu

rusty@hodge.UUCP (Rusty Hodge) (05/28/88)

In article <873@ucsd.EDU>, brian@ucsd.EDU (Brian Kantor) writes:
> 	3. I'll just have to wait a few years until the old farts with 
> 	this kind of attitude problem die off and do ham TV when I'm welcome.

I've found that it is more fun to bug the old farts to death.  Make 'um
nervous enough, maybe they'll drop off sooner with their heart or
something.

This is exactly why I haven't gotten in to Ham-TV.  Everyone makes it
so hard to do anything interesting (packet excepted).

Reminds me of how they screwed up the best fleamarket/swap meet I've
ever been to: the TRW Swapmeet here in So. Cal.  They kicked all the
computer people out; and you have to show proof of license and membership
in a ham radio club(!!!) to sell there.  Before, anyone could just come
and sell.  It was super-popular.

> Why do you suppose they bother to advertise?  

Tax Write-Off.  That and the "Look what I've got and you don't!"
attitude.  Argh.

jans@tekcrl.TEK.COM (Jan Steinman) (06/01/88)

(Discussion about cheap, low power TV transmitters led to:)
<<P.C. Electronics...>>

<When I called them they seemed to be a bunch of weird people...  Besides the 
"please wait while we look you up in the Callbook to see if you're really a 
ham", they also INSISTED that I contact a local ATVer before I order anything 
from them so that I'd be sure to understand all about ham TV.>

If they are who I think they are, they have good reason to be somewhat 
secretive.  They do not adequately supress the vestigal sideband, and put out a 
6MHz-wide signal, rather than 4MHz, so they will not fit in the television 
allocation for the band plan.  Instead, they've plopped the thing on 436, which 
makes weak-signal types furious, and possibly violates international law and/or 
FCC regulations.  In any event, this device CANNOT be re-crystalled for a 
"normal" channel without causing interference, and CANNOT be operated north of 
the "A" line (roughly Seattle to Green Bay) because of international 
regulations.

If I mixed them up with someone else, I apologise.  Is this the ~$150 box?  It 
would be difficult to build a 4MHz-wide box at that price.  Be suspicious of 
anything under about $300.

:::::: Software Productivity Technologies -- Experiment Manager Project ::::::
:::::: Jan Steinman N7JDB	Box 500, MS 50-383	(w)503/627-5881 ::::::
:::::: jans@tekcrl.TEK.COM	Beaverton, OR 97077	(h)503/657-7703 ::::::

larson@unix.SRI.COM (Alan Larson) (06/01/88)

In article <2693@tekcrl.TEK.COM> jans@tekcrl.TEK.COM (Jan Steinman) writes:

-> If they are who I think they are, they have good reason to be somewhat
-> secretive.  They do not adequately supress the vestigal sideband, and
-> put out a 6MHz-wide signal, rather than 4MHz, so they will not fit in
-> the television allocation for the band plan.  Instead, they've plopped
-> the thing on 436, which makes weak-signal types furious, and possibly
-> violates international law and/or FCC regulations.  In any event, this
-> device CANNOT be re-crystalled for a "normal" channel without causing
-> interference, and CANNOT be operated north of the "A" line (roughly
-> Seattle to Green Bay) because of international regulations.

I don't think they are who you are thinking of.  They advertise crystals
for 426.25, 434.0, and 439.25.  They do not mention 436 MHz.

By the way, being on 436 should be little trouble to the weak signal
activity on 432.1.

	Alan


p.s.  The only bad think I can think of to say about them is that
      they still ship with UPS.

karn@thumper.bellcore.com (Phil R. Karn) (06/02/88)

> By the way, being on 436 should be little trouble to the weak signal
> activity on 432.1.

Except that it could be a lot of trouble to satellite users. The
satellite segment on 70cm runs from 435 to 438 Mhz, and it is actively
used for both uplinks and downlinks by several satellites.

I find it interesting that certain ATV repeaters use channels that include
the 435-438 Mhz segment, even though repeater operation there is prohibited
by the rules.

Phil