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  #1  
Old 07-28-2008, 06:36 PM
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Richard D Richard D is offline
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Low power VHF transmitters

Has anybody had any luck in finding a low power VHF transmitter for us folks who collect Panasonic CT-101's and other portable sets? I have tried some of the video "senders" from you know where and they drift al over the place, even if no one is walking by. I also tried a Ramsey transmitter block for RC vehicles. It was only a little better and very expensive.
Thank's to all,
Richard.
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Old 07-31-2008, 07:16 AM
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jhalphen jhalphen is offline
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Hello Richard,

I also collect CT-101s and the whole range of Panasonic & other brands micro-TVs.

Back in 2004, after much searching about low power TV transmitters, i discovered Greek company Aspisys and their 80mW synthesized TV transmitters. I purchased PAL B/G and NTSC versions.
The original product was unpackaged, just a PCB.

http://www.aspisys.com/tvpll.htm

Two years ago, they brought out a newer model capable of all major world TV standards in a single model with 100mW of RF power.

All in all, i have 8 transmitters (a mix of the new & old versions), future-proofing myself against the blackout of analogue TV.

My two main transmitters (PAL & NTSC) operate 15 hours/day with no reliability problem whatsoever since 2004.

The units produce quasi-broadcast quality pictures, however they don't use vestigial sideband filtering, so can't qualify as true "Broadcast".

The signal is good & strong and allows "off whip" TV reception from anywhere in the house (give or take a few blind spots).

Personally, i repackage the units in an aluminum box. This gives adequate cooling to the +5 and +12VDC integrated regulators which run rather hot, not being heatsinked in the original design, and of course better RF shielding which the plastic case does not provide.

You can Email for info here:

info@aspisys.com
sales@aspisys.com

Aspisys is run by a very knowledgeable engineer with great competence in the RF and video fields. You can communicate easily in English.

Pictures:
#1 shows the original 2004 design (PLL TV Sender)
#2 shows the Aspysis RF test gear, serious stuff!
#3, 4 show my repackaging of the original transmitter
#5 shows the current version of the TV transmitter (UTV-100TX)

*disclaimer: i have no interest ties with Aspisys.

Best Regards

jhalphen
Paris/France
Attached Images
File Type: jpg Aspisys PLL TV Sender-01.jpg (38.3 KB, 25 views)
File Type: jpg Aspisys PLL TV Sender-02.jpg (52.5 KB, 24 views)
File Type: jpg JH PLL TV Sender-02-VGA.jpg (69.5 KB, 28 views)
File Type: jpg JH PLL TV Sender-03-UXGA.jpg (34.2 KB, 17 views)
File Type: jpg Aspisys UTV-100-TX TV Transmitter-03.jpg (53.1 KB, 25 views)
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  #3  
Old 08-03-2008, 07:35 PM
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Richard D Richard D is offline
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Thank You very much for the information, it looks like they build quality equipment. Depending on cost I would like to get 3 or 4 NTSC transmitters. That way I can retransmit several channels at once.
Regards,
Richard
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Old 08-04-2008, 12:01 AM
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kbmuri kbmuri is offline
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Richard D,

I tried to PM you but your box is full.

Search that ePay place for "Blonder AM60*". Item 380051569880 will completely take care of you (no personal affiliation with the seller/item, and all the latest disclaimers to that effect), and it's priced really well, so if somebody else grabs it now, too bad your PM box wouldn't accept my message.

The reason you're not getting a lot of replies on this thread is because transmitting your own TV signals is a pretty "iffy" thing to do, FCC-wise. Use the modulator responsibly and at your own risk. Properly set the gain pot up front, and a very small antenna in back will suffice, to keep the radiated RF power low. Else expect a knock on the front door by Men in Black. I suspect if you fed a rooftop antenna at full gain it would go half a mile or so. I wouldn't go there. A little telescoping-rod antenna and a 1/3-gain setting, and you stay within your 4 walls and everybody's happy.

Advantages over the crap Ramsey box or the cheap "sender" ePay things, is it's a commercial-grade unit instead of a toy. It has sideband-filtering (aka "Broadcast Quality"), is crystal-controlled everywhere, is fully shielded, is fan-cooled for thermal stability, and it works. It's what you're looking for, and then some.

You can set whatever output channel you want, VHF or UHF. Dip switch settings on the front panel. Buying 3 or 4 of them will work like you want too.

My 2c. Give it a try.

- Kirk
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  #5  
Old 08-04-2008, 05:51 PM
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Richard D Richard D is offline
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Help!!

How do I empty my PM box? I tried everything I could think of. THANKS TO ALL!
Richard
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  #6  
Old 08-04-2008, 10:21 PM
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bgadow bgadow is offline
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Richard,
Pull up your list of PM's; check the box to the right next to each one you want to delete. Now go down to the bottom of that list and you will see a drag-down box that says "move to folder..." Open that box and chose "delete" and then go. Don't forget that it also saves messages you sent; you can use the little box above the message list to switch to that list and delete what you no longer need. I barely know what I'm talking about, but since I knew the answer I figured I'd post!
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  #7  
Old 08-05-2008, 07:58 PM
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Richard D Richard D is offline
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Thank's to all who helped me figure out the difference between incoming and sent mail
CHEERS
Richard
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