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Old 9-Dec-2012, 6:26 PM   #1
b2471041
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Antenna choice help inner sunset San Francisco

I tried a pre amp omnidirectional antenna on the roof and did not get any better results than an indoor antenna near the TV on the ground floor ( about 30 channels). The experiment in various places did show probably the better placements for where a good antenna should go on the roof.

TV fool analysis:
http://www.tvfool.com/?option=com_wr...cc49ec131a62a7

Probable setup ~150 ft RG-6 coaxial cable, 3 TV’s and a lead to a forth location, 3 splitters. Roof is 30 feet up, but I am on the north side of a small mountain. Since I am running the coaxial it will run to some rooms that will not have a TV part of it will tie in to already cable coaxial where it easy to switch. I get cable internet so I can't switch the whole system.

I would like to and haven’t been able to get yet is NBC KNTV which is high on the VHF HI spectrum. It broadcasts off of San Bruno mountain which is south of me and there is no line of sight with at least one hill in the way which I am on the side of. It is only a little over 5 miles away. I think, part of the problem is I am close to and can see the Sutro towers which are blasting FM signals.

I will take any advice.

Mark
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Old 10-Dec-2012, 6:52 AM   #2
GroundUrMast
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Expect any amplifier to overload...

When this close to signals that are extremely strong, reception of otherwise easy signals calls for use of a high gain antenna aimed at the weaker signal. Amplifiers are going to make your problems worse, not better.

Your TVFR indicates the top dozen signals are overpoweringly strong... the top three are predicted to be able to overload a typical tuner.

You could try an Antennacraft Y10713 pointed at 145°. You may need to add an FM trap and attenuator with 10 to 20 dB of loss. I would try with no attenuator to begin with, the extremely powerful UHF signals are going to easily get in via the antenna even though it's designed for high-band-VHF.

http://www.radioshack.com/product/in...LA&cagpspn=pla
http://www.antennasdirect.com/store/...on_filter.html
http://www.amazon.com/In-Line-Coac-C...ref=pd_sim_e_6

In extreme cases (yours is approaching that) a second FM trap may be required.
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Old 10-Dec-2012, 10:08 PM   #3
b2471041
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Thank you for your help.

Thank you for your help. I will post a followup to this thread after I got the results (what combination worked well). Hopefully anyone who lives nearby and is looking for info it will help them.

I had been playing around with FM traps before I posted. Here is a good place to get them and other small things: http://www.mcmelectronics.com/produc...FQtxQgodDAkA4g

Thanks,

Mark
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Old 2-Jan-2013, 5:08 AM   #4
b2471041
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Followup to Antenna choice help inner sunset San Francisco

I got advice from a number of people including Antenna Direct. I decided to go with a Antenna Direct High Gain Digital VHF Antenna Clearstream 5 because of the smaller foot print than the antenna suggested earlier in this thread. Bingo. I used it, 2 TV Interference filters http://www.mcmelectronics.com/produc...=prodCrossSell and I was able to block out the FM signals and gain the high VHF NBC station 5 miles away but two mountains. Also I got all the UHF I got with an indoor antenna plus a few more. Even though this antenna is for picking up High VHF signals it also pickups UHF signals so if you buy it try it first by itself and you may not need a UHF antenna. The Clearstream 5 comes with an antenna combiner box if you do need another antenna.
No amplification used.
Pictures on all TVs look great.
Thanks

Last edited by b2471041; 2-Jan-2013 at 5:10 AM. Reason: added: No amplification used.
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Old 2-Jan-2013, 6:39 AM   #5
GroundUrMast
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Your report is consistent with other reports of the UHF capability of the CS5.

Enjoy!
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Old 2-Jan-2013, 6:57 AM   #6
Stereocraig
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It would be nice, if that interference filter at MCM had a better description.
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Old 3-Jan-2013, 6:30 PM   #7
b2471041
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75 ohm noise filter

Quote:
Originally Posted by Stereocraig View Post
It would be nice, if that interference filter at MCM had a better description.
I inquired for further details from MCM and got:

This is a 75 ohm noise filter that goes in-line with the antenna. We have no other information.

Gary
Technical Advisor

MCM Electronics
T 937-434-0031
T 800-543-4330 x58755
F 800-765-6960
E techc@mcmelectronics.com
www.mcmelectronics.com
650 Congress Park Dr.
Centerville, OH 45459

I am sure it is just your standard FM filter.
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