Category Archives: ATV

Amateur Television – a beginning

Yesterday I went out for Chinese at lunchtime. My fortune cookie said “Begin…the rest is easy.” I hope that’s true.

Tonight I began the first step of getting on the air with ATV. I was sent a M369 TV Modulator by the fine folks at Cadco Systems. This unit should be able to output approx 10mW, though I haven’t yet measured it.

I’m feeding it into an M2 HO Loop antenna right on the workbench. I was able to receive a signal a couple dozen feet away. I consider this phase to be a success.

The next step is to get some amplifiers together to boost the power to 15W. At that point I have a lead on a high power amplifier that I can build that should be able to get me up to around 400W sync power. I also need to find a 32V power supply.

More to come!

 

 

Where the heck is W0HC?

Sometimes life gets in the way of Ham Radio.  Such has been the case at the W0HC QTH.

In the past month I've mostly finished the tower.  Just some minor odds and ends to tie up before the snow flies. The grounding panel is built, the Polyphasers are installed. Coax is run. The tree is trimmed. And the beam works! I was able to work a station in Croatia over the past weekend, and made a few stateside contacts on 10m. The beam is awesome! I'll try to get some pictures of the finished tower, and the grounding panel soon.

As for life, it's just been busy. A weekend on the road, continuing DTV conversion stuff at work, getting all the power equipment ready for winter, etc.  And we are now involved in a FIRST Lego League team, which I'm excited about.  It's pretty neat to see a group of 9-14 year olds getting excited about engineering, even if they don't yet realize that it's engineering.  Right now they are researching lots things about vehicles, like how tracks are used on tanks and other heavy equipment, alternative energy sources, and other things of that nature.  And they are having fun building with Legos!  We have a group of about 15 kids, several of which are girls.

I'm still messing around on the side with some ATV stuff.  I have my modulator working, and have a couple of small amplifier modules sitting on the bench waiting for me to hook them up and try them out.  The main thing that's slowing me down is still the lack of a high power amplifier.  But, I may have some leads on a few, ranging from 100w to 400w. That should do nicely!

Just a quick update

I have a "new" (actually refurbished) ATV modulator to mess with.  It was donated to me by CadCo systems, and has firmware that allows it to be frequency agile.  I hope to get a chance to mess with it soon.  I will defiantly have more to say about this.

I'm starting to cook up some plans to operate on Field Day.  Our local club didn't seem to have any interest in doing FD, so I'm going planning to do it on my own.  So far I have a half dozen or so people that plan to come along.

And in other news, I'm still working on plans for a tower.  I think I get some used Rohn 25G that will fit my budget, so I may start digging a hole as early as tomorrow.

More later.

ATV

For as long as I’ve been involved in amateur radio I’ve wanted to get into Amateur Television (ATV).  I just never seemed to have the money to get started.

Now that DTV has made NTSC Television more or less obsolete, there is starting to be some surplus equipment available.  I suspect that more and more NTSC equipment will be hitting dumpsters as the year progresses.  So far I’ve been able to secure a few items to get me started.

Exciter- I picked up a couple of frequency agile UHF modulators.  They output about 15mW of RF.

I also have a couple of amplifiers designed to take about 10mW of television RF and amplify it up to a couple of watts.  From there it feeds yet another amplifier, and finally, a driver section out of an old low power transmitter that should make 50W or so.  Ideally I’d like to make at least a few hundred watts.

Ultimately I plan to make this into some sort of ATV repeater, obviously the output will be in the 432MHz band.  The input will likely be 900MHz and possibly 2.4GHz as well.  I don’t yet have receivers for either.  Yet.  But I have my eye on some that are pretty reasonably priced.

Whenever I mention this crazy scheme to anyone I get the inevitable question:  “what are you going to transmit”?  The answer to that is, “I don’t know”.  Anything.  Everything.  It seems like it could be a very valuable tool for emergency communications.  We could send back live video from the scene of a disaster, and rebroadcast it so that any agency in the county would be able to see it.  Or it could transmit live weather radar during storm spotting events.

So far I’ve only gotten far enough with this project to determine that I need to get different firmware in the modulators to allow them to transmit in the ham band.  Once I get past that hurdle I can hopefully make some progress on my new journey into ATV.