Part 15 TV Transmission

[luRaichu]

I heard about a guy running a low power AM station from their house under FCC Part 15, without a licence and was wondering if there's anything like that for TV broadcasting.
According to an answer on https://ham.stackexchange.com/questions/12568 you can transmit on unused UHF channels 14-51 unlicenced.

[Phil]

15.241 Operation in the band 174-216 MHz.

(a) Operation under the provisions of this section is restricted to biomedical telemetry devices.

15.242 Operation in the bands 174-216 MHz and 470-668 MHz.

(a) The marketing and operation of intentional radiators under the provisions of this section is restricted to biomedical telemetry devices employed solely on the premises of health care facilities.

The only thing I could find in CFR 47, Part 15 regarding this. Radiating a television signal on television channels appears to be illegal. Period. However, operating a "in-house cable system" is not, since it is not an intentional radiator.

[Electronic M]

Most TV collectors transmit low power anyway (mostly on VHF). If you are doing so on your own property at a power level low enough that your neighbors won't have an easy time receiving it and choose unused RF channels in your area you'll probably never bother anyone or be bothered. Most analog TVs are out of use so there's not much out there that will notice your signal especially if it doesn't go any significant distance.

[kf4rca]

There are stations here on the vhf band in HD. So operating on the old vhf band could be a problem. There's WUVM operating on old channel 2 and WXIA operating on old channel 10.
It was my understanding that this band was to be re-allocated to land mobile.

[Electronic M]

Originally Posted by kf4rca

There are stations here on the vhf band in HD. So operating on the old vhf band could be a problem. There's WUVM operating on old channel 2 and WXIA operating on old channel 10.
It was my understanding that this band was to be re-allocated to land mobile.

Yup out here RF carriers exist on ch 5 and 8. Several DTV tuners (like the Zenith DTT-901) allow you to manually tune the RF carrier channels and see signal strength, and there are websites that list all stations that can possibly be received in your area and their RF carriers...If you pick a carrier channel that nothing in your area uses and you adjust your transmit power down to the minimum your property needs nobody will be bothered.

[Tube TV]

Highest I transmitted was the to the top end of the BT modulator I think it was between Channel 27 & 28. No clue what the range was but I would guess it was under a block. Around the house the signal was spotless. These days I've been on channel 7 with a dipole antenna tuned to it and getting good coverage with the modulator set pretty low.

[DavGoodlin]

I got on ebay as soon as I knew what VHF freqs were re-allocated to the area. The antennas are in the attic of garage with a metal roof. This is perfect for radiating toward the house.

Fortunately, I am somewhat rural. Just staying off of channels 2-6-8-10 and 13 would make for a good neighbor, though 8 and 10 are our only "local" stations. I use 3-7-11 and 12. These are fed direct A-V composite from a Funai (Magnavox or Philco) DT converter. These are fairly trouble free ones that stay on 24/7, set to channels appropriate to flip through on an old set.

The MAVM aand BAVM series modulators output a great signal for these older analog tuners, far better than RF3 or 4 connection to a STB or VCR.

[kf4rca]

Have you seen this?
https://www.ebay.com/itm/38810052615...Bk9SR4a-nojCZQ

[jhalphen]

Hi to all,
Hi KF4RCA,

Bandersen has tested this unit, 3 videos on YouTube.

1st test:
https://youtu.be/L7-Tf4rkdAE?si=xHCiMOP-xyT3PFvL

2nd test (sound problem):
https://youtu.be/u0OdxKc5yxs?si=AsZbg30Y6hwKzk0u

3rd test:
https://youtu.be/XX7iyPNWQ2s?si=hEL1Lcq0dUyEjhy6

Another unit, higher power, 2 (Chinese!) Watts is better:
https://youtu.be/GrduUgedrW8?si=eBojw6v-HN_xYUHe

Recap & good to know:
Units use China's analog TV frequency plan and channel spacing, 8MHz. USA is 6MHz.
As a result, only US Channel 10 (nearly) coincides for vision carrier & audio carrier.

For CCIR Euro countries UHF System G, the Chinese Tx is spot-on.
On VHF, China's frequency plan is different vs Euro VHF system B.
China used 8MHz wide VHF vs 7MHz in CCIR (Euro) System B.
see US & China frequency allocations in attached files.
Last photo is the 2W higher power TV Tx.

Hope this helps,

Best Regards
jhalphen
Paris/France

[kf4rca]

Thanks for the info. I'll just wait till the "B" model version comes out. You would think that with all the Chinese made TV's coming ashore, they would know the USA frequency plan.

[kf4rca]

Don't know if you've ever thought of this. If you have a B&K1076 or 77, there are some resistors you can change in the plate circuit of V4 and you can get more power. V4 is a triode and I think you might can get a watt out of it.

[bandersen]

Tyler the "Antenna Man" is launching an antenna signal strength meter.
https://youtu.be/morth_5eZDQ?si=sKtulJFQQqk6sNCs

[DavGoodlin]

Originally Posted by bandersen

Tyler the "Antenna Man" is launching an antenna signal strength meter.
https://youtu.be/morth_5eZDQ?si=sKtulJFQQqk6sNCs

Tyler lives not to far away from me, based on the channels he gets. He is living the dream I had 15 years ago. I have to catch up with some of this stuff.

[kf4rca]

If you're looking to enhance your distance and can't increase power, you might try a high gain antenna. Forget about super turnstile and roto-tiller antennas. Here's a link for a 9db gain diy antenna. Depending on what frequency you choose, it might be quite large.
https://www.repeater-builder.com/ant...-from-coax.pdf

[DavGoodlin]

Originally Posted by kf4rca

If you're looking to enhance your distance and can't increase power, you might try a high gain antenna. Forget about super turnstile and roto-tiller antennas. Here's a link for a 9db gain diy antenna. Depending on what frequency you choose, it might be quite large.
https://www.repeater-builder.com/ant...-from-coax.pdf

That antenna looks quite interesting. If someone built that, a picture would help show what you end up with in practice.

I had an elective Antennas/Propagation class in college that re-ignited my interest in antenna design, I cut the cable way back then.
The DTV transition 21 years later had me getting into old designs after I saw some silly junk on the internet claiming unreal reception distances reminiscent of Radio Shack's advertising. The old designs were better but covered a wider UHF spectrum that could be tweaked. Jerrold Channel Master Winegard Finco JFD S&A all made some very good designs even by today standards, all different.

When broadcasting, reduction of standing waves is a factor when tuning the antenna. I have just used a 1/4 wave dipole for VHF and bowtie for UHF via RG-6U about 10 feet from BT modulators. Broadband antennas that are directional are another option, but the best may be a 5-element yagi tuned for flat 6mhz on the specific channel, aimed at your studio.