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28-Sep-2017, 12:58 AM
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#1
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Junior Member
Join Date: Sep 2014
Posts: 6
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Need help with DIY Antenna Design
Hey Folks, I live in the mountains of southwest Virginia. I plan to build a DIY antenna and would like input on the best design and size for my situation. My house is about 1600 feet elevation with nearby mountains that are are 3000 to 4000 feet high. If I cannot get direct signals, I am hoping that maybe I can get reflected signals. Any advice and help is appreciated. Dave
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29-Sep-2017, 8:41 PM
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#3
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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It is the real channel number that determines what antenna is needed.
VHF-Low, real channels 2-6
VHF-High, real channels 7-13
UHF, real channels 14-51
The virtual channel number (like 5.1) is a holdover from the analog TV days to maintain the identity of the station, and is what the TV displays.
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I plan to build a DIY antenna and would like input on the best design and size for my situation.
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A DIY yagi antenna for channel 5 would have elements about 6 feet wide; for 7 and 11, about 30 inches.
A ready-made antenna for VHF-Low and VHF-High would look like this:
https://www.solidsignal.com/pview.asp?p=hd8200u
this is their house brand equivalent
https://www.solidsignal.com/pview.asp?p=HD8200XL
Last edited by rabbit73; 29-Sep-2017 at 8:48 PM.
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29-Sep-2017, 8:47 PM
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#4
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Junior Member
Join Date: Sep 2014
Posts: 6
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I believe channel 5 also broadcasts on a UHF channel. If I need 6 foot long elements and a 500 foot tower it sounds like its not going to be feasible.
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29-Sep-2017, 11:34 PM
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#5
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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WCYB also has a transmitter on channel 29, but it is too weak for you even with your antenna at 50 feet.
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29-Sep-2017, 11:53 PM
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#6
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Junior Member
Join Date: Sep 2014
Posts: 6
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Rabbit, I really appreciate your help. Is my situation hopeless to get TV OTA? Can you give me a scenario where I might be able to get a few channels (i.e. Antenna size and design). Reinvesting some money from the cable company to a big antenna might be worth it?
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30-Sep-2017, 1:16 AM
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#7
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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No, I don't think it is hopeless, based on your signal reports.
VHF channels are used for hilly terrain areas because VHF signals can make it over hills better than UHF signals.
I will work on a scenario and try to think of some inexpensive tests for you to make.
Last edited by rabbit73; 30-Sep-2017 at 2:32 AM.
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30-Sep-2017, 1:50 AM
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#8
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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Quote:
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If I cannot get direct signals, I am hoping that maybe I can get reflected signals.
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You might be able to receive WCYB and WJHL directly or from a reflection off the hill just north of the highway with the big Solid Signal HD8200XL antenna and a preamp.
For something smaller, you might be able to receive WJHL directly or off a reflection with the MCM 30-2476 and a preamp. The MCM antenna is inexpensive, but is on backorder. Put your name on the backorder list.
http://www.mcmelectronics.com/produc...-2476-/30-2476
redirects to Newark which is now combined with MCM
http://www.newark.com/stellar-labs/3...14_US%2Fsearch
Manufacturer: STELLAR LABS
Manufacturer Part No: 30-2476
Newark Part No.: 71Y5462
Quote:
Check stock and lead times
639 Further stock expected to ship on Oct 1, 2017
More stock available week commencing 1/1/18
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Last edited by rabbit73; 30-Sep-2017 at 1:59 AM.
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30-Sep-2017, 6:02 PM
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#9
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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This shows the hill just south of your location that blocks the WCYB 5 signal:
The WCYB signal coverage is very spotty in rough terrain:
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30-Sep-2017, 6:32 PM
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#10
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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The hill also blocks WJHL:
WJHL is weaker than WCYB:
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30-Sep-2017, 8:08 PM
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#11
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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This is a contour map of the WCYB signal path and two hills:
WJHL signal path with hill coordinates:
Last edited by rabbit73; 30-Sep-2017 at 8:40 PM.
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1-Oct-2017, 1:10 AM
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#13
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,753
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Oblique view looking North, showing your location and Hills A and B:
Last edited by rabbit73; 1-Oct-2017 at 1:13 AM.
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2-Oct-2017, 1:41 PM
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#14
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Senior Member
Join Date: Sep 2016
Posts: 244
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What if he got landowner permission to put an antenna up in a tree on "Hill B", which is about 700 feet away. If he used RG-11, the losses even at the high end of UHF (700 MHz) would be around 20 dB. A CM-7777 pre-amp has 30 dB of gain, so it seems like this could work? I found a 1000-foot role of RG-11 for only $100. If he put in on "Hill A", the run is closer to 1000 feet but since the signals are about 20 dB stronger there, Hill A might be the better option.
Or maybe even the unmarked hill, (I'll call it Hill C), located about 1000-feet west of Hill B?
Possible coax source:
https://www.cablewholesale.com/products/coaxial-cable/rg11-bulk-...
Last edited by jrgagne99; 2-Oct-2017 at 2:01 PM.
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2-Oct-2017, 1:58 PM
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#15
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Senior Member
Join Date: Dec 2014
Posts: 342
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Either that or put up a dual antenna to capture and re-transmit the signal down to his location.
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2-Oct-2017, 2:25 PM
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#16
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Senior Member
Join Date: Sep 2016
Posts: 244
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Does anybody on the forum have direct experience with this approach?
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6-Oct-2017, 5:04 PM
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#17
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Senior Member
Join Date: Dec 2014
Posts: 342
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I've seen a post on it, someone did it for a location in WV i believe. I'll look around for it.
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6-Oct-2017, 5:13 PM
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#18
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Member
Join Date: Feb 2015
Posts: 39
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6-Oct-2017, 5:20 PM
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#19
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Senior Member
Join Date: Dec 2014
Posts: 342
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Doesn't need to be that technical. It's basically just 2 antennas, one aimed at the towers, the other aimed at your house. Connected to each other with a short coax cable.
I'd try the bow tie style antennas with reflectors to block reception from the back side.
That is if you have permission to put them up on one of the hills.
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6-Oct-2017, 5:32 PM
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#20
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Member
Join Date: Feb 2015
Posts: 39
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Sorry.
I not the OP 
Just found the topic interesting.
See other post for my situation
http://forum.tvfool.com/showthread.php?t=15276
Wish this idea was used by my now shutdown home owner's cable system.
Maintenance cost of the ridge head end facility forced the shutdown.
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