tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
 ·Verizon Online DSL
edit:
October 6th, @11:50AM
| OTA Antenna upgrade
My son and I installed a new antenna system over the weekend, to get ready for Feb 2009 analog go dark. We are in southern NH about 42 miles from Boston and 35 from NH stations. Currently have 20 year old outdoor antenna with separate VHF and UHF antennas and preamp.
New system consists of Channel Master 4228 UHF and Winegard YA-1713 VHF high antenna and Channel Master 7777 mast mounted preamp. Signal is split with 8-way splitter to multiple rooms, not all of which are in use. Preamp has enough gain to compensate for cable and splitter loss plus about 10 dB. That way Noise Figure of TVs can be ignored and only Noise Figure of preamp counts. New system is at least 2 dB better then old not counting effects of 20 years outdoors.
Results have been confusing:
1) Analog VHF (even VHF low) and UHF is significantly improved.
2) Converter box (Insignia NS-DXA1-APT) reports stronger signals and picks up more digital stations. Signal is reported as bar graph - no numbers.
3) TV tuner card (Hauppauge HVR-1600) reports lower signal strength for most stations and some we used to get are no longer viewable. A couple of local channels are reported as stronger. Card reports SNR as a numeric. If signal drops below 15 unable to display. Since DTV SNR threshold is 15.2 dB I assume display is in dB but not sure. Typical Boston station used to report as 21/22 now reports as 19/20.
As sanity check to exclude problems with wiring to specific TV used a splitter (3 dB loss) and installed Converter box on same drop as PC tuner card. Converter still performed well and reports strong signal even when TV tuner card is unable to even display channel.
Added a 10 dB attenuator with splitter. TV card reported lower signal strength. Leads me to believe preamp is working as advertised and really has 10 dB gain over cable/splitter loss.
The fact signal level on at least some local channels is reported higher then before indicates new antenna/amp is working correctly.
Anyone have any ideas – I’m stumped.
/tom |
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McSummation
Mmmm, Zeebas Are Tastee.
Premium,MVM
join:2003-08-13
Round Rock, TX | I would say the tuner card is not as sensitive as the converter box. |
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SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL | reply to tschmidt
Bad TV Converter card, Bad connection at the TV card.
Those are my guesses.. |
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leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
clubs: 
| reply to tschmidt
With those symptoms I would check for too much amplification (either amplifying noise or multipath reception).
Is that pre-amp wired in such a way that it would be relatively easy (for test purposes) to bypass it ?
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Got some spare cpu cycles ? Join Team Helix or Team Starfire! |
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tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
·Verizon Online DSL
| said by leibold  :Is that pre-amp wired in such a way that it would be relatively easy (for test purposes) to bypass it ? Unfortunately preamp is mast mount and now that antenna is installed is difficult to access. Preamp has 26 dB gain. Wiring loss and splitter have about 16 dB loss at UHF frequencies. That is why I added 10 dB attenuator 2-way splitter. Overall gain seems about correct. There are no strong TV or FM stations that could account for overload.
What I find so confusing is that it does not affect all devices equally. I must have hit on some bizarre combination. Multipath may be the explanation. We are in rural NH but due to terrain have problems with reflections. Early reports about 8-VSB DTV were that it did not fair well in the presence of multipath. Newer generation tuners have ameliorated that problem. I've been pleasantly surprised even in presence of severe multiplath (when antenna is pointing elsewhere) how well signal is processed.
/tom |
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tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
·Verizon Online DSL
edit:
October 7th, @05:51PM
| reply to McSummation
said by McSummation :I would say the tuner card is not as sensitive as the converter box. That is a possibility but I don't think it can be just raw sensitivity. Newer antenna system is better since converter box is able to display more stations. That implies signal is stronger. This may be a multipath problem as leibold suggested that affects tuners in different ways.
/tom |
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tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
·Verizon Online DSL
| reply to tschmidt
Re: OTA Antenna upgrade - follow up
Looks like digital section of TV tuner card failed. Appears to be a coincidence it happened at same time we ungraded antenna.
Analog TV and FM radio portion of tuner card work as advertised but am no longer able to directly receive any DTV channels. Converter box continues to receive more stations then with old antenna.
While I'm not happy losing a $80 tuner card at least is appears to resolve the mystery.
/tom |
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SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
·AT&T Southeast
| said by tschmidt :Looks like digital section of TV tuner card failed. Now how much money did I have in on this bet?  |
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