OTA antenna/preamp suggestions in PA - AVS Forum
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post #1 of 10 Old 12-13-2002, 06:42 PM - Thread Starter
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Hi,

I'm located in northeastern PA and am having difficulty receiving all of the HDTV stations in my area. I am currently using a Winegard HD4053 for VHF and a Blake JBX21-WB for UHF, coupled by a CM Titan 7777 preamp on a 28' mast. All coax is RG6 quad-shield with snap-n-seal connectors. There are a few hills between me and the transmitter locations and my home is surrounded by many very tall trees. Here is my current reception status:

WNEP-DT 49 = 70% (33 miles from the 68KW transmitter)
WVIA-DT 41 = 75% (33 miles, 200KW)
WBRE-DT 11 = no lock, digital LED flashes on/off a few times (33 miles, 30KW)
WYOU-DT 13 = no lock, no flash (33 miles, 30KW)
WBNG-DT 7 = no lock, digital LED flashes on/off a few times (57 miles, 20KW)

Obviously I am having a big problem with the VHF stations. My thought is that with my current setup the VHF antenna has about 5db less gain than the UHF antenna, and the Titan provides 3db less gain on VHF than UHF. I need increase my VHF signal by at least 8db somehow.

I am considering swapping out the HD4053 for a Jerrold VIP307SR (VHF broadband) which has about 3db increased gain. Any thoughts on this or other deep fringe VHF antennas?

My next question- what do do about the preamp. I am considering switching to a Winegard AP8275 which will increase my VHF gain by 6db over the Titan. Any comments on this choice of preamp?

My last question- how should I combine the 2 antennas since the AP8275 is a combined 75 ohm input:

Option A) Connect the VHF antenna to the AP8275. Connect the Blake UHF to the existing Titan. Run 2 downleads inside the house and combine the signals onto one coax after the preamp power supplies. (This way I don't have to take the combiner loss before amplifiying the weak signals)

Option B) Combine the 2 antennas before the AP8275 and run one downlead into the house.

I would appreciate any suggestions!

John
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post #2 of 10 Old 12-14-2002, 08:10 AM
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Quote:
Originally posted by jhutchey
I am currently using a Winegard HD4053 for VHF and a Blake JBX21-WB for UHF, coupled by a CM Titan 7777 preamp on a 28' mast. All coax is RG6 quad-shield with snap-n-seal connectors.

WBRE-DT 11 = no lock, digital LED flashes on/off a few times (33 miles, 30KW)
WYOU-DT 13 = no lock, no flash (33 miles, 30KW)
WBNG-DT 7 = no lock, digital LED flashes on/off a few times (57 miles, 20KW)

Obviously I am having a big problem with the VHF stations. My thought is that with my current setup the VHF antenna has about 5db less gain than the UHF antenna, and the Titan provides 3db less gain on VHF than UHF. I need increase my VHF signal by at least 8db somehow.
Obvious question: Have you tried it without the preamp? My preamp introduces a fair bit of noise into the VHF stations and actually requires a very strong signal before the noise is overridden by the signal. VHF is also far less sensitive to line-of-sight issues and probably doesn't need the same boost in gain.

Also, all of those power numbers are pretty low, even for VHF. Have you contacted the station's engineer to see if they plan on boosting power? My experience in contacting them is that they are very interested in what the digital signals are doing.

The gain numbers of VHF for your antenna are actually very good. The only design that might do better is one of the Televes models (but you have to order five and have them shipped from the UK...) The Channel Master preamps do have a tendency to overload, though, if you've got a bunch of strong signals (analog or digital.)

One thing to try (crazy as it sounds) is a variable antennuator. This may reduce the strength of the "noise" and let the signal in cleanly.
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post #3 of 10 Old 12-14-2002, 10:10 AM
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The main thing..in top reception (with no dropouts or blocking) is to get a very strong signal at the antenna. It is OK to try a pre-amp, of course, but expect no magic from it. At least, this has been my experiecne. Of course, the more money you spend the more gain on a UHF and a VHF antenna. Quality of construction usually goes hand in hand with the more money part. At 52 miles, witha reasonable line of sight, I get 'almost' perfect reception with a Televes DAT75 UHF..average gain of 16.5. Of course, very important is how much power the station is sending out. On those VHF stations..did you say?..analog or digital?...All my digital?HD stations are on stations above 14 so are all on the UHF band. So, I can not comment on VHF.
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post #4 of 10 Old 12-14-2002, 12:06 PM
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Antenna gain and preamp gain are not fungible. You already have more VHF preamplifier gain than you could possibly need. Might you be near an FM radio station that is overloading the VHF section of your preamp? The 7777 preamp has a switchable FM trap, but some internal FM traps don't attenuate the entire FM band. Try installing an FMT-88, which does block out the whole FM band, if you are really close to an FM transmitter, or if you are fairly close to one at the low end (88Mz-92Mz) of the FM band. They only cost a few dollars.

If you are near a channel 2-6 transmitter, then insert an HLSJ band joiner to attenuate 2-6. They cost just a few dollars. Any chance that you are near a cell phone or pager tower? Ask a local professional antenna installer if you are. Midband traps (120Mz-174Mz) can typically be bought for $20 to $40, but they just might compromise channel 7 a little. You are better off with a weak (-20dB) midband trap, like the one that Winegard used to make and that you can still find on dealer's shelves now and then, than with a deep (-40dB to -50dB) trap like the cable company uses as a tier trap to wipe out cable midband channels.

You have a good antenna, but if you are desperate, try a Blonder-Tongue BTY-LP-HB. it has 13.2dB of gain on channel 7, and 12.2dB of gain on channel 13, versus the 9.6dB on channel 7 and 10.6dB of gain on channel 13 by you present antenna.

Any requests for advice on anttena selection should be acompanied by a zip code or map coordinates.
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post #5 of 10 Old 12-14-2002, 12:31 PM
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Of course if you are really serious about spending money on a big antenna you could try a Ron Smith aerial, I have read that the FM galaxy series can be used for VHF as well but they are big and pricey.

40° 42' 17" N 89° 36' 57" W
If a station is broadcasting and no-one can receive them, then are they broadcasting?
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post #6 of 10 Old 12-14-2002, 04:02 PM - Thread Starter
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Quote:
Originally posted by AntAltMike
Any requests for advice on anttena selection should be acompanied by a zip code or map coordinates.
My location is 41.38°N, 75.28°W

AltAntMike,

I do not believe I am located near any transmission towers of any type. (I don't even get very good cellular reception at my house.) I am located kind behind hills that are blocking a clear path to both Binghamton and Scranton television transmitters. The heavy tree cover doesn't help either. My UHF reception even with the Blake is so-so. I'm thinking of stacking a second one and adding another 10' to my mast.

However, I do think you are on to something with the FM overload. Although I do get a good (slightly snowy) picture from WBNG-12 out of Binghamton, analog channels 3 and 6 out of Philadelphhia have a ton of (cross channel?) interference in them such as wavy lines, etc. Once the snow melts I am going to get up on the roof and try the FM filter ahead of the preamp and verify also that the 7777's built in FM trap is enabled.

One reason I was thinking of using the broadband 307SR rather than a highband VHF antenna was the possibility of getting channel 4 out of Binghamton once they start broadcasting. Do you feel I will have better results sticking with a highband only model? If so, I suppose I can live without ABC from Binghamton since I am getting halfway decent results with ABC WNEP-DT out of Scranton on UHF.

Do you think the 7777 is the best preamp for my situation? Should I be looking at another model or seperate preamps for UHF and VHF?

-John
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post #7 of 10 Old 12-14-2002, 08:48 PM
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I punched in your coordinates (41.63 deg, 75.46 deg, in decimals) into the NIA calculator and you seem to be less than 40 miles from both the Scranton and Binghamton towers.

I also ran what I believe to be your zip code, 18510, through the CEA calculator and it shows that you would need the smallest possible antenna with no preamp to receive 9 and 13, and a medium gain antenna with a preamp to get 7 and 11. You have a large antenna and a large preamp, so you most likely are overloading the preamp, and are probably overloading your tuner inputs as well. I'd try it without a preamp before even experimenting with the various filters
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post #8 of 10 Old 12-15-2002, 06:14 AM - Thread Starter
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AltAntMike,

I actually live in ZIP 18436, which puts me much further out in the countryside. I've already asked the engineer at WBRE/WYOU about the NIA database, and he said that it did not accurately take into account the terrain. Here's an example: NIA indicates I should be getting a city grade signal on WNEP analog but even with a preamp and the Blake I am getting considerable snow. Without the preamp there is no picture at all. I get a good (but still a bit of snow) picture on WDAU and WBRE with the preamp, but without I get a ton of snow. Believe me, I am really located in an area with crappy reception and I need all of the gain that I can get.

I have also tried CEA's antennaweb calculator for 18436, but I am not getting good results with it at my location. I have used it for locations closer to town, and it is indeed accurate and the aiming map works. Unfortunately my address apparently isn't in database and I have no idea where in 18436 the aiming map is representing. And it definately is not indicative of my location- I originally tried the "small directional+preamp" as suggested and did not get anything but a few snowy stations. Then I moved up to a large directional Winegard (without preamp), then added the preamp, then the large Blake+preamp, then increased my mast to 28'.

When the local digital VHF stations came online, I took into account their relatively low output power and my track record on the UHF stations and started with the HD4053+CM7777.

As I posted earlier, once the snow is off the roof I am going to try the FM filter. I am also going to experiment with VHF reception without the preamp and see what happens.

Thanks for your replies. I really appreciate it.

-John
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post #9 of 10 Old 12-15-2002, 10:56 AM
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John,

You might try hiring someone with a bucket truck or tall platform lift to help you do a site survey with your antennas 40-60ft above ground level.It could make a huge difference,getting up above some of the ground clutter.
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post #10 of 10 Old 12-15-2002, 11:35 AM - Thread Starter
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Maxhd,

My antennas are now located about 50' above ground level (2 story home + 28' mast). Unfortunately I am surrounded my very tall trees and would need at least another 30' to get above them.

I have thought about doing a site survey of other parts of my lot, but my property owners association requires that any antenna has to be on the roof (i.e. no 96' free standing tower in the front yard). I did do a "walk around the roof with a 10' mast" survey to find the optimum location before permanently installing the taller mast.
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