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KC2SYK
07-21-2010, 06:29 PM
Hello, all. I was thinking about getting a video baby monitor, which are used under Part 15 (unlicensed low power) here in the US. I was hoping that there are models that use NTSC modulation on the ham ATV frequencies, and that after the baby is grown, I could modify it to be a ham ATV transmitter/receiver pair.

There seem to be several models that use the 2.4GHz band, but I need to do more research on the modulation and frequencies used.

Has anyone done this or given it a try before? Are there any models that are known to be easily modded or already use the appropriate modulation and frequencies?

Any general advise about this? I've not done anything with ATV yet, so this question is asked as a total newbie. Thanks.

Thanks and 73.
-Chris KC2SYK

ad4mg
07-21-2010, 06:40 PM
My baby rearing days are long behind me, Chris, but welcome to the Island! Our regional experts, who actually answer questions, should be along shortly. Charles is our bartender, and he's the best! Have fun!

KC2UGV
07-21-2010, 07:00 PM
At least once it has been done (Albeit inadvertently):
http://www.dailymail.co.uk/news/article-462184/Baby-monitors-world-transmission-space-shuttle-Atlantis.html

KG4CGC
07-21-2010, 07:05 PM
Welcome to The Island! We have cookies!
I am your barkeep. Please pull up a deck chair at the bar located at the end of the the pier and grab a pole, the mahi are always biting.

http://i25.photobucket.com/albums/c79/bebop5/5_mixed_drinks.jpg

We have those damned umbrella drinks!

WØTKX
07-21-2010, 07:08 PM
Almost any camera that does NTSC works, and a cheapo (free) TV can be the RX. http://www.hamtv.com/

It would be fun to try... there's very little activity here, except occasional portable demos.

There is an ATV repeater system in NJ, maybe it in range for you? http://www.qsl.net/kd2bd/atv.html

KC2SYK
07-21-2010, 07:32 PM
Thanks for the welcome, AD4MG and Charles. I'll have a scotch, please. :) Jeff, W4GPL, had been talking about this forum for a while, thought I would give it a shot for my unusual question.

KC2UGV, yes, I had heard of that before, which had gotten me thinking about this.

W0TKX, yes, I'm aware of the 70cm NTSC/CATV RX possibility. I was thinking that doing it with some hacked up babycam would be an interesting challenge. That ATV repeater might be reachable with a directional antenna from here. I can hear some FM repeaters in that area from here, so it might be possible. I don't think any of the babycams are in the 70cm band though, I would need to get a different TX for that band.

Thanks and cheers!
-Chris KC2SYK

WØTKX
07-21-2010, 08:19 PM
Welcome to the Island, Chris. Happy Happy Joy Joy!

Due to the need for bandwidth, moving a typical 49 mhz baby monitor to 6 meters would be OK for voice only, the TV signal would not be legal. You could use the camera section of the baby monitor... or a video camera. Many point and shoot cameras have a video out... that RCA adapter. Point is, most of us have a camera that could be pressed into service.

I have a cool B&W Panasonic portable that I got for free with a variable tuner... it works! Video on 440, audio on 144 seems to be the common method, and you can use cheap radios. You might try a simple corner reflector antenna to see if you can pick up the locals... and a VHF/UHF TV yagi will work OK on receive.

Of course, you could use SSTV... aka sending a high speed color fax. ;)

Hams have historically found uses for old junked TV sets. I love this radio stuff!

W4RLR
07-21-2010, 09:00 PM
Welcome to The Island, Chris!

While I cannot be of assistance in your ATV question, I would like to say that we're glad to have you here. In spite of what you may have heard about this place on that "other forum" you will find that we are 99.95 percent 'vermin free'.

A relaxed, laid back atmosphere is what you will find here. No selective moderation, no 'anointed ones', and the freedom, within reason, to speak your mind so long as you don't sink to the level of ad hominem attacks. There's people from all walks of life and all political persuasions here, and we all get along.

Glad to have you here!

KC2SYK
07-21-2010, 09:05 PM
Right, a generic video camera would do the job. I was thinking of using it on the 2.4GHz band mostly. Not sure if that is used at all except maybe for the input side of an ATV repeater, however. 70cm seems to be preferred for the output side due to the CATV RX possibilities.

-Chris KC2SYK

KC2SYK
07-21-2010, 09:11 PM
Hi Richard, thanks for the welcome. I don't know about any history with other forums, so I'll leave that to others.

Thanks and cheers.
-Chris KC2SYK

N8YX
07-22-2010, 11:28 AM
Welcome, Chris!

WRT ATV - there used to be a lot of activity around the Akron, OH area and still is a sh!t-ton of it around the Columbus region.

You might want to do a little digging around on one of the sponsoring club's websites and see what the members are up to in the way of equipment.

w3bny
07-22-2010, 02:22 PM
I was under the impression that any TV or VCR that received..uhh..upper cable channels was pretty much there for receiving 70cm ATV. Transmitting, different story but the reception was pretty easy.

WØTKX
07-23-2010, 01:31 AM
Some TV's have a variable for tuning UHF... frequently hits the frequencies, tweakable if not.
The click click ones are OK if there is a fine tuning knob. Channels 57, 58, 59 and 60.

I have an old VCR that will "fine tune" and a portable B&W
TV with the variable KNOB® that will hit those channels.
I've tried the portable when a local ham group was playing with
ATV for a bicycle race, and it worked.

Have not tried the VCR, but now I have an excuse not to throw it away.

KC2SYK
07-23-2010, 10:49 AM
You might want to do a little digging around on one of the sponsoring club's websites and see what the members are up to in the way of equipment.

Thanks for the welcome, N8YX. That's a great idea about the Columbus clubs. I know they have an ATV repeater facility or two over there. This seems to be the major one: http://www.atco.tv/RepeaterInfo.aspx with 70cm, 1.2 GHz and 2.4 GHz operation. I'll drop them an email and see what they come back with. Thanks for the idea, and cheers.

-Chris KC2SYK

KC2SYK
07-23-2010, 10:54 AM
Some TV's have a variable for tuning UHF...

Gah, I forgot about this. The last TV I had with a fine-tuning control was from the 80s. The modern ones seem to have AFC you can't disable, plus demanding (high SNR) video squelch. Thanks for the reminder.

-Chris KC2SYK

KC2UGV
07-23-2010, 11:04 AM
Gah, I forgot about this. The last TV I had with a fine-tuning control was from the 80s. The modern ones seem to have AFC you can't disable, plus demanding (high SNR) video squelch. Thanks for the reminder.

-Chris KC2SYK

If you want an older TV, I can send you one. It needs a variable resistor to be soldered on (The vert sync), and it's a small B&W, 12V portable. But, fine tuning is there. No charge. It does work, I powered it from my bench right into the battery compartment (Couldn't find a connector for 12V in).

WØTKX
07-23-2010, 12:39 PM
If they don't "dial" low enough in frequency, many of those old school tuners are easily "re-tunable" below channel 14 , which is 470-476...

Kind of fun watching the screen go weird tuning local FM repeaters. :lol:

KA5PIU
08-01-2010, 09:31 PM
Hello.

Nearly all video baby monitors are 900 MHz now, a few are at 2.4 GHz but that is now the exception as this tends to conflict with WiFi.
The 420 MHz baby monitors use FM video as a rule, much like the 900 MHz counterparts, cheaper and easier to implement.