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Old 17-Jan-2017, 12:02 AM   #1
Junior Member
Join Date: May 2016
Posts: 3
attenuate 2 UHF OTA TV channels


I have a situation where I have 2 channels that come in extremely strong, but all other channels (2 hi-VHF and 2 UHF) are very weak, so weak, that those channels can only be tuned with a preamp. However, because the preamp also "boosts" the extremely strong channels, I'm getting pixelation and other distortion issues, probably due to overload on the TV tuners.

So, I'm thinking that I'd like to attenuate the 2 UHF OTA TV channels that have extremely strong signals. Both ABC (RF 16 - UHF) and CW (RF 34 - UHF) are only around 9 miles away and the signal from both are always 98%+ signal strength either directly to the TV or through the HDHomeRun Extends. I can actually put the antenna on the ground in the opposite direction of the tower and still easily get the signals from ABC and CW.

Since the weak channels are both VHF and UHF, I can't just have separate VHF & UHF antennas, and then only use a preamp on one of them like you usually could. I think I need a way to attenuate the extremely strong UHF channels, but not the weak VHF & UHF channels.

What do I need in my situation? Are there inline filters that can attenuate specific channels and adjust independently for the 2 separate channels?

thanks for any information in advance.


TV Fool Report



- Winegard HD7698P antenna on 20ft mast.
- 2 different outdoor preamps that I can experiment with:
- currently using Winegard LNA-200 Boost XT Outdoor Digital TV Antenna Amplifier (max gain 18 dB).
- Channel Master CM-7777 Titan 2 High Gain Preamplifier (max gain 30 dB).
- 3 HDHomeRun Extends.
- rg11 outdoor direct burial coax between antenna and house.
- quad shielded rg6 from attic to 3-way split to 3 HDHomeRun Extends.
- HDHomeRun Extends connect to home network (all cat6 cabling) to Win10 server with NextPVR software which can be output to any TV/device in the house either wired or wireless with proper app.
- Fire TVs are wired to home network with HDMI connection to TVs.



- in Florida, obviously very flat, but in a slight depression, next to a canal with hundreds of 50ft+ pine trees on either side of the canal.

- Antenna is pointed south toward towers, mostly parallel to canal and slightly upwards over the pine trees. After lots of experimentation, I found this brings in the best signal. I've spent hours moving & pointing the antenna in lots of different locations, directions, angles, and heights.

- antenna is pointed almost due south, directly at the NBC and CBS tower, which have the weakest signals. There's about 150ft opening between the pine trees on the back of my property that I point the antenna up and through.

- I tried smaller antennas, but because of my situation with the canal and pine trees, only a large antenna like the HD7698P worked with NBC and CBS (and I still need a preamp for that to work).

- I have a neighbor with an antenna setup that is 1 mile farther away from the towers, but not on a canal or in a depression, and his channels come in perfect with no preamp, and, with a much smaller antenna (Denny's HD Stacker antenna).



- without and with Winegard LNA-200 Boost XT Outdoor Digital TV Antenna Amplifier (max gain 18 dB)

- getting numbers from TVs, HDHomeRun Tuner Status page, and the "Signal GH" iPad app. Numbers match from all sources. Obviously, signal is slightly stronger directly from antenna to TVs.

- without an outdoor preamp, I only get 2 channels, ABC and CW. With an outdoor preamp, I get all channels, even in most bad weather.

- However, with preamp, I'm getting occasional pixelation and distortion on all channels.

- I don't think any of the percentages can go above 100% so I really don't know what the peak ss/snq/seq are.

ABC (RF 16 - UHF)
485 MHz
- path LOS
- 9.3 miles to tower
- ss74%/snq100%/seq100% no preamp
- ss100%/snq100%/seq100% with preamp

CW (RF 34 - UHF)
593 MHz
- path LOS
- 9.3 miles to tower
- ss68%/snq98%/seq100% no preamp
- ss100%/snq98%/seq100% with preamp

FOX (RF 28 - UHF)
557 MHz
- path LOS
- 47.9 miles to tower
- ss27%/snq41%/seqNONE no preamp (no channel reception)
- ss94%/snq89%/seq100% with preamp

PBS (RF 27 - UHF)
551 MHz
- path LOS
- 47.9 miles to tower
- ss25%/snq41%/seqNONE no preamp (no channel reception)
- ss92%/snq89%/seq100% with preamp

NBC (RF 12 - hi VHF)
207 MHz
- path 1Edge
- 47.3 miles to tower
- ss18%/snq40%/seqNONE no preamp (no channel reception)
- ss80%/snq85%/seq100% with preamp

CBS (RF 13 - hi VHF)
213 MHz
- path 1Edge
- 47.4 miles to tower
- ss17%/snq40%/seqNONE no preamp (no channel reception)
- ss73%/snq81%/seq100% with preamp

Again, thanks for any insight into my situation.
tahlyn is offline   Reply With Quote