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Discussion Starter #1 (Edited)
Hi, I live near Nazareth, nearish to Philly. I'm trying to get WPVI, rf channel 6. Here's my tvfool report. https://www.tvfool.com/?option=com_wrapper&Itemid=29

I have a winegard 7694p approx 25' above ground level feeding a rca tvpramp1r preamp with 20' rg11 going to a hdhr3.

I can try to make a dipole antenna (with a reflector and director?) to get WPVI. Is that a good idea, or is there something to be bought that would work? For what it is worth, when I touch the antenna, I can see the signal strength, signal quality, symbol quality go to the level where the channel is watchable. When I let go, everything drops off. I don't want to buy a new vhf/uhf antenna because I like the one I have. I'm just trying to get that one channel.

As an aside, I tried pointing my antenna toward w07dc, the WNEP translator, but couldn't pick it up. I think that signal is headed north northwest from that tower, whereas I'm more northeast of that tower.

Thank you for your help.

Mike

Edit: here is the tvfool report link, sorry about that.
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=8e039d75017694
 

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when I touch the antenna, I can see the signal strength, signal quality, symbol quality go to the level where the channel is watchable. When I let go, everything drops off.
When you touch what antenna, the 7694 25' in the air or a dipole?
 

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Sorry- when I touch the 7694. I assume when I touch the 7694, I then become part of the antenna making it much larger.
That's logical.

Do you want to make a channel 6 antenna to mount near the 7694?

There aren't any VHF-low only antennas being sold, only big all channel antennas like the Winegard HD8200P or 7084.
 

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Discussion Starter #5
That's logical.

Do you want to make a channel 6 antenna to mount near the 7694?

There aren't any VHF-low only antennas being sold, only big all channel antennas like the Winegard HD8200P or 7084.
I searched and didn't come up with any low vhf only antennas either. I am willing to try to make an antenna to get channel 6. I found this and thought it would lead me in the right direction in making an antenna http://nt1k.com/blog/2012/homebrew-5-element-vhf-yagi/

Would that link above be a good jump off point? I think it would be fun to make an antenna. Would a reflector and directors make a big difference? What about a reflector with 1 director?

Out of curiosity, is receiving w07dc not a possibility? http://www.rabbitears.info/market.php?request=print_station&facility_id=73325
I don't think it would be given its low power and directionality, but wanted to run that by you guys.
 

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Stark Electronics still lists Blonder Tongue lowband antennas:

Stark Electronics BTY-5-LB 4866 Antenna Single Channel Low-Band VHF/FM, 5 Elements, 54-88/88-108MHz CHANNELS:2,3,4,5,6,FM $749

I bet if you called Toner Communications and were serious, they'd sell you one for under $500. Just a guess.

One thing about these pricey Blonder Tongue antennas is they are durable, making them suitable to withstand the windage on highrise buildings, but they only get you a few more dB than a large, junky residential broadband antenna.

 

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I tried pointing my antenna toward w07dc, the WNEP translator, but couldn't pick it up.
WNEP is a mere 25 watt signal at its maximum using a very directional transmitting antenna. A mere 2 watts is calculated to be pushed in your direction. You will never see that signal at your location.

FM antennas usually will cover channel 6 adequately in many situations. Looking at the data sheet for the Antennas Direct 3 element FM antenna (http://www.antennasdirect.com/cmss_files/attachmentlibrary/FM3.pdf), it appears to be a fairly close match for also covering channel 6. You'd have to combine its signal with your existing antenna using an HLSJ combiner.

I found this and thought it would lead me in the right direction in making an antenna http://nt1k.com/blog/2012/homebrew-5-element-vhf-yagi/
Yes, but keep in mind that the design shown is for the 144-148 MHz amateur band. You'd have to re-scale the design to cover the 82-88 MHz band which can be done crudely by multiplying every dimension by ~ 1.7.
 

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Wade lists one
http://www.wadeantenna.com/product.php?p=288

http://www.wadeantenna.com/us-distributors.php

Would that link above be a good jump off point?
That's a good start, but you are not quite there yet. Ham antennas are designed for 50 ohms; you want 75 ohms or 300 with a 4:1 balun.
Would a reflector and directors make a big difference? What about a reflector with 1 director?
Yes, a 3 element yagi would be a big improvement over a dipole.

For a DIY yagi I suggest a folded dipole for the driven element; easier than a gamma match.

Old Delhi CH6 yagi (3-wire DE)
http://www.digitalhome.ca/forum/186-antenna-research-development/139654-delhi-5y-10y-channel-cut-vhf-yagis-saved-oblivion-diyers.html

Interesting article on WPVI
I’ve Got The Low-Band DTV Blues (June 2009)
http://www.hdtvexpert.com/hdtv-tech-talk-i%E2%80%99ve-got-the-low-band-dtv-blues-june-2009/
 

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When you touch what antenna, the 7694 25' in the air or a dipole?
Sorry- when I touch the 7694. I assume when I touch the 7694, I then become part of the antenna making it much larger.
How do you touch the antenna that is 25 feet in the air?



I was once stacking a couple of channel 6, cut to channel antennas in a harsh reception situation, relying on visual feedback from a guy in the building, watching the analog picture on a large, test TV, and he kept giving me nutty feedback, alternating between "That's better." and "Now it's worse" when I was seemingly doing nothing at all, other than moving around the roof. The stacked pair worked best when I was standing between the dipole and nearest director of the lower antenna. It seems that I was a human attenuator, and the pair minimized the ghost image when the lower mounted antenna was attenuated slightly, so I moved out of the antenna cross section, then put a variable attenuator on that line, and adjusted up and down until centered in on optimal picture quality. It was something I could do with analog signals that we can't do with digital ones... and something worth doing for a 260 unit assisted living community that you likely could not justify paying for yourself.
 

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I did an fmfool report based on your estimated location, which puts you close to Veterans Memorial Square.
http://www.fmfool.com/modeling/tmp/cb635d2f96/Radar-FM.png

You can do your own FM report here to see how close I was. The FM reports don't link the same way as TV reports; you have to make an image or create a link:
http://www.fmfool.com/index.php?option=com_wrapper&Itemid=29

What I'm looking for is to see if there are strong local FM signals that might interfere with TV reception.

WODE-FM, with a signal strength of -14.7 dBm, is the strongest of your first three signals, and is 42.4 dB stronger than WPVI. They are in the center of the FM band and not close to CH6. I'm not sure if you will need an FM filter. The specs of the FM filter in the RCA preamp are unknown. The MCM FM filter would probably harm CH6 reception, as would the Antennas Direct FM filter. The Radio Shack FM filter is designed to allow reception of CH6, which is just below 88 MHz.





 

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Hi, I live near Nazareth, nearish to Philly. I'm trying to get WPVI, rf channel 6.

I have a winegard 7694p approx 25' above ground level feeding a rca tvpramp1r preamp with 20' rg11 going to a hdhr3.

I can try to make a dipole antenna (with a reflector and director?) to get WPVI. Is that a good idea, or is there something to be bought that would work? For what it is worth, when I touch the antenna, I can see the signal strength, signal quality, symbol quality go to the level where the channel is watchable. When I let go, everything drops off. I don't want to buy a new vhf/uhf antenna because I like the one I have. I'm just trying to get that one channel.

As an aside, I tried pointing my antenna toward w07dc, the WNEP translator, but couldn't pick it up. I think that signal is headed north northwest from that tower, whereas I'm more northeast of that tower.

In my experience you have to have a real low VHF antenna mounted outdoors to receive those stations. Indoor antennas (even attic) are subject to weak signals and multipath even more than the higher frequencies. Then there's the higher noise level on low VHF. You should replace the HD7694P with the HD8200U.

Alternately you can make a low VHF log periodic. The lowest antenna in my avatar is the one I made. Works fine. I receive a 3KW channel 4 station 115 miles away essentially 100%. No preamp necessary.

I don't know why you're not receiving W07DC as it is plenty strong and LOS. It should be easy with an outdoor antenna.
 

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I was once stacking a couple of channel 6, cut to channel antennas in a harsh reception situation
I once stacked a couple of broadband antennas for channel 12. Worked great. Just gotta make sure that the jumpers from the transformers to the splitter are precise.
 

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http://users.wfu.edu/matthews/misc/dipole.html

Channel 6, 82 to 88 MHz, center frequency 85 MHz.

5540/85 = 65.2 inches length for a folded dipole antenna

To convert the dipole antenna into a 3 element beam for more gain, add a reflector and a director:

Reflector is 105% of Driven Element = 65.2 x 1.05 = 68.5 inches

Director is 95% of DE = 65.2 x 0.95 = 61.9 inches

One wavelength in air is 11810/freq in MHz = 11810/85 = 138.9 inches

DE to Reflector spacing = 0.2 λ = 138.9 x 0.2 = 27.8 inches

DE to Director spacing = 0.15 λ = 138.9 x 0.15 = 20.8 inches



Dimensions are approximate and should be optimized with computer modeling, which I don't do.

W07DC has co-channel interference from WABC-TV that is 12.2 dB weaker, but a directional antenna should be able to handle that, if the FM interference doesn't get to it.
 

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Discussion Starter #17
I love coming to this forum, everyone is very helpful - thank you. Rabbit, I will make an antenna based off your schematic. I have a very busy next few weekends, but I'll report back how it went.

AntAltMike, good question on how I touch the antenna when it's 25' agl. The 7694 is mounted on a flat roof. I just hop out the window and do what I need to do.

I have two more questions. Using a HLSJ, do I combine the two antennas and then run the combined signal through the preamp, or do I combine the two after the preamp? Egnsln, you mentioned the jumpers from the transformer to the splitter need to be precise, do that mean that the cable length from the channel 6 antenna and from the 7694 to the hlsj need to be the exact same length?

Thank you again.

Mike
 

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If you are into DIY Antennas, ANY of the following can be Rescaled by multiplying ALL Dimensions (incl. approximate Element Size) by the fol. Rescale Factor F = Current Center Frequency / Desired Center Frequency:
http://imageevent.com/holl_ands/yagis [Includes both OPTIMIZED DIY and some Commercial Antennas you could copy.]

Although 300-ohm Twin-Lead might be okay for an INDOOR Ch6 Antenna, moisture and Ice/Snow will result in significant Losses. For Outdoors, it would be better to use a 1-in or 3-in PVC Tube and "wrap" some (say AWG-12 House Electrical, no need to strip insulation) Wire around the ends and attach a Balun to the Midpoint of one Wire. Be sure the PVC Tubing is SEALED to prevent moisture ingress:
http://imageevent.com/holl_ands/loops/vhffoldeddipole

But Folded Dipole only provides about 2.0 dBi Raw Gain.

Fol. DIY Ch6 Hourglass-Loop (NO Reflector) provides 5.0-5.4 dBi, but are 7-feet HIGH, rather than 7+ feet LONG....perhaps more suitable out of sight in your Attic. I recommend using AWG12 (as above), strung on a fairly rigid, cross-braced PVC Box Frame:
http://imageevent.com/holl_ands/loops/lovhfhourglassloopnorefl
Even Higher Gain and suppression of Multipath is possible by adding Reflector Rods:
http://imageevent.com/holl_ands/loops/ch2ch3hourglassloopreflrods
 

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The 7694 is mounted on a flat roof. I just hop out the window and do what I need to do.
Excellent; an ideal place for antenna experiments.
I will make an antenna based off your schematic.
If you use tubing for the elements, they should be supported at the center. If you use wire for the elements they should have good insulators at each end. The ends of the elements are high impedance points and must be well insulated for low loss.
does that mean that the cable length from the channel 6 antenna and from the 7694 to the hlsj need to be the exact same length?
No, that is only necessary when you are combining two identical antennas aimed in the same direction with a splitter in reverse as a combiner for more gain.
Using a HLSJ, do I combine the two antennas and then run the combined signal through the preamp, or do I combine the two after the preamp?
Good question. This is where you are going to need to experiment, because the Joker in the deck is your strong local FM signals that might interfere with TV reception.
http://www.fmfool.com/modeling/tmp/cb635d2f96/Radar-FM.png

The general rule is to make sure you have what you want from each antenna before combining. There is no point in combining until your CH 6 antenna works for WPVI.
 

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The first tests are to try the CH6 antenna alone

1. CH6 Ant > coax > tuner

2. CH6 Ant > HLSJ (Common & Low ports) > coax > tuner

Test No. 2 attenuates the first 3 signals (9, 39, and 46) on your report but doesn't attenuate your FM signals. You can see the Low Port curve allows FM to pass.



If you still don't get WPVI it could be from FM interference. The Radio Shack FM filter allows CH6 to pass with very little attenuation.

3. CH6 Ant > Radio Shack FM filter > HLSJ > coax > tuner

 

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