Agile modulator broadcasting
 

Picked up a Blonder Tongue CAMS-60 agile modulator on ebay in hopes of being able to transmit cable TV throughout the house :)

The system works incredibly well on DVD, but for standard cable in, would I be able to use an old cable channel box and an RF modulator? I tried to interface with the Time Warner cable box, using the video and audio outs, and nothing.

I don't quite understand... you have *no* audio or video out of your T/W cable box? How do you normally connect it to the TV? Perhaps the analog output is disabled if the HDMI is used?

jr

It works with my TV, but not with the agile modulator.

Your cable box is now probably all digital and it does not understand an analog signal coming at it. And it is mapped by TW to only look for their digital signals on their channel assignments which are in a language all of their own. The video inputs on the box are near useless. Any old box will not work as the cable world is now all digital. And I am assuming a modern set...not a vintage 2-13 set.

Their actual channel 55 in the spectrum may show on your box as virtual 155 or any other channel they tell it to display. There is no cure for this. To borrow a phrase..."we control the vertical, we control the horizontal"...and all settings.

Your only solution is to run the set direct from the wall and find an empty channel and use the wall connection combined with the BT to fool your set. This wall signal is only the local stations that they have to carry but that will end soon. FCC gave permission to the cable ops to drop this service recently. It will go away at some time but you can still use your BT in the end as below.

You have to find a digital cable RF test unit and scan your cable input before the box and find an empty channel and then add the BT via a combiner (backwards splitter) on that channel to the antenna input. If you scan your set, it will find the BT channel. You may have to refine the RF levels from the BT as digital works with a much lower signal. Lower the BT RF output level to match.

I do this at home. Most sets have component/HDMI and I use this with my box for pure cable from the box. I then use the separate antenna input for the cluge from above. And the wall input for HD is usually better than the box while it lasts. The BT channel will outlive the transition but be lonely on your set in the end as long as the cables do not dedicate that channel for broadband.

When they fill the spectrum I will think of something else. Stay tuned.

No, this is a vintage 2-13 set. Right now, it's the Sony 8-301W to test things out with.

I'm thinking cable (as in before the box) to 1980s TV cable box to channelize, then to an RF demodulator, to the agile modulator. I wonder if I can use an old VCR as an RF demodulator....

That's what I do, VCR as a demodulator.

You need to haul your ass over to the Orlando Hamcation sometime. This year I saw two for a quoted $20 each, and you probably could have talked the guys down even further since they seemed eager to get rid of 'em. (I got one the year before for $5.)

EDIT: Huh, I just now noticed the last reply was quite awhile ago... for some reason it showed up in the 'new posts'. Weird.

I also live in Daytona now. ;)

Hello, if it's alright I would like to continue this thread.
I have on order a Blonder/Tongue AM series modulator from eBay. It is not the model with BTSC stereo however.
It is my intention to start using it to transmit on an open channel around my home. As I collect more tv sets, it will be very nice to own one of these.
Does anyone have any tips or tweaks as to how I shall orient my antenna, both receiving and transmitting? I will need to cover about 150 foot area. Is this possible with the quoted RF output power of 60dBmV?

Well I suppose this thread has bitten the dust. After preliminary testing, the RF output seems sufficient; I have found a tutorial on tuning the antennae elements to a specific frequency, which helped my signal strength a fair amount. Now, I just need to finalize orientation of the xmitter elements.

Could you post where to find this tutorial? It sounds interesting.

Hi, Tom C., I found this at youtube when I searched for Blonder-Tongue Labs.
http://youtu.be/z4dhRt7tmd4
This guy knows his stuff.. After doing what he said, my modulator threw out a lot more distance.