OTA question

[1069_KIFR]

I use Over The Air Television Broadcast. Just upgraded to a new TV. I get EVERY Channel I want to see, Crystal Clear, except for KGO Channel 7 and KICU Channel 36. KGO is blank and KICU freezes. Any ideas how I can receive these two stations?

 

[e-dawg]

Which part of the bay area do you live?

Since I live in Ingleside neighborhood of San Francisco, I can picked up all the bay area stations except for:
KDTV 14 (Univision)
KRCB 22 (PBS)
KFTL-CA 28 (IND/HSN)
KAXT (PSIP: CH1) IND
KMMC-LP 40 (Tres)
KTNC 42 (Estrella TV)
KSTS 48 (Telemundo)
KEMO 50 (Azteca America)
KTLN 68 (TLN)

 

[1069_KIFR]

I'm in San Bruno

 

[fybush]

Depending on your elevation and exactly where in San Bruno you're located, you may be somewhat terrain-blocked to KICU's South Bay transmitter site. Entering your address into tvfool.com will tell you how much KICU signal you should expect to be getting and whether you're seeing it line-of-sight or "1-edge" (i.e., there's something between you and KICU and the signal's bouncing around it or off it to get to you.)

As for KGO, you should have plenty of signal at your location from KGO on Sutro. But - KGO remained on VHF channel 7 when everything else on Sutro went to UHF physical channels. If the antenna you're using is UHF-only, it can't see 7 well enough to produce a usable signal.

If everything else is solid for you, it sounds like upgrading your antenna would pay off immensely.

 

[1069_KIFR]

Thanks Scott, I'll look into that!

 

[w9wi]

As an EXCEEDINGLY general rule...

Indoor antennas with "ears" (as in the old-fashioned "rabbit ears") are suitable for all channels. Models without the "ears" are for UHF only.

Be wary of "amplified" or "boosted" antennas. In San Bruno, you're not that far from the mountain of the same name -- where many transmitters (both TV and FM) are located. An amplifier can overload, making reception *worse* and potentially generating interference to channel 7.

 

[KeithE4]

As an EXCEEDINGLY general rule...

Indoor antennas with "ears" (as in the old-fashioned "rabbit ears") are suitable for all channels. Models without the "ears" are for UHF only.

I have one of those amplified VHF-rabbit ears/UHF-log periodic Terk antennas, and I'm 5 miles from the South Mountain antenna farm in Phoenix. With 3 channels on VHF-hi (8, 10, & 12), I found that shortening the rabbit ear elements to about 14" each (1/4 wavelength at Channel 10) helped. For Channel 7, make them about 16". You may have to move the elements around if you get more than 1 VHF channel.

Be wary of "amplified" or "boosted" antennas. In San Bruno, you're not that far from the mountain of the same name -- where many transmitters (both TV and FM) are located. An amplifier can overload, making reception *worse* and potentially generating interference to channel 7.

Buy an FM trap and connect it between the antenna and the preamp. It worked wonders for me, even on UHF channels. A dozen or so FM stations at 100 kW each, 5 miles away, caused the antenna's preamp to overload. Connecting it between the preamp and the TV won't do anything since the FM signals will still be amplified and cause intermod in these rather poorly-designed amplifiers. The intermod products inside the TV bands won't be rejected.

 

[fybush]

I'm with Doug - I wouldn't even THINK of using an amplified antenna (even with an FM trap) anywhere within sight of Mount San Bruno. With all those powerful FMs up there (88.5, 93.3, 94.9, 95.7, 99.7, 102.9, 105.3, 106.1, 107.7), it's almost a guarantee that there's some intermod that will land inside of TV channel 7 (174-180 MHz) and wreak some havoc with reception there.

 

[w9wi]

Buy an FM trap and connect it between the antenna and the preamp. It worked wonders for me, even on UHF channels. A dozen or so FM stations at 100 kW each, 5 miles away, caused the antenna's preamp to overload. Connecting it between the preamp and the TV won't do anything since the FM signals will still be amplified and cause intermod in these rather poorly-designed amplifiers. The intermod products inside the TV bands won't be rejected.

Good point, about shortening the "ears". On many of these, the ears can be adjusted to match any RF frequency -- including those WAY below that on which KGO broadcasts. We have found reception on RF-10 can often be improved by collapsing the ears to about the length Keith mentions.

The problem with the FM trap thing, is that in most cases with indoor antennas, the preamp is part of the antenna and it's not possible to connect an FM trap between the two.

However, it might not be a bad idea to consider using an FM trap between the (unamplified) antenna and the TV. I didn't realize KQED was on Mt. San Bruno; its second harmonic falls squarely within KGO's frequency band & your TV may be generating 2nd-harmonic interference even without an amplified antenna.

 

[compubit]

One other consideration for KGO is that they're broadcasting on both 7 (Sutro) and 35 (South Bay). Some TV's see a second signal for a channel, then drop the first. KGO/35 may generate enough signal in your locations for the tuner to throw out KGO/7 and then it can't reliably lock on 35, resulting in a black screen.

Just another thought.

J

 

[kenglish]

Talking about the "FM Trap"....
I remember a trick from many, many years ago (probably some place like "Popular Mechanics" magazine) where you could take a piece of twin-lead, and connect it across the 300-Ohm terminals on your set, then try shorting through the insulation at small intervals using a razor blade.
The idea was to short the wires and make a tuned stub at about 1/2-wavelength for a particular frequency that was interfering. I guess you could try hanging the twin-lead stub off of the two rabbit-ears.
Might be worth a try.