Low VHF antenna designs
Greetings everyone.
Since it is near impossible to purchase a low VHF band specific antenna, It would be nice to have the information to build one. Personally, I'd prefer a Low Band VHF antenna that covers Rf 2-6. Currently, I've been using FM antennas to receive Rf 6 with fairly good results. I'm finding FM antennas harder and harder to find for purchase. Please include specific spacing, reflector, director measurements. Appreciate your help!! |
You're right Joe... Finding any commercially made L-VHF antennas has become nigh-on-impossible. I've just finished installing 4NEC2 antenna modeling software on my new computer so as I get back up to speed with it expect me to offer a few contributions to this thread. In the meantime, there are a few calculators available online.
Examples; https://www.changpuak.ch/electronics...enna_DL6WU.php https://www.changpuak.ch/electronics/Dipole_folded.php https://www.changpuak.ch/electronics...da_antenna.php http://www.vk5dj.com/yagi.html https://www.qsl.net/4nec2/ |
Really appreciate your information. I cannot help but
wonder if a low band VHF antenna, that covers Rf 2-6, would differ from the channel specific designs you provided???? |
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If you need even more bandwidth, the next step up would be a Log-Yagi which has log periodic active elements combined with parasitic elements. An example would be the VHF-High section of an RCA ANT751. https://i.imgur.com/0HMm9FY.jpg And finally, for the greatest bandwidth you would need a Log Periodic antenna design. Examples would be the VHF-High section of the Winegard HD7698P and the VHF-High/VHF-Low section of the Winegard HD-8200U. https://forum.tvfool.com/attachment....3&d=1565736363 https://forum.tvfool.com/attachment....2&d=1565726635 The small extensions that you see on some of the 8200 VHF elements allow those elements to function on 2-6 AND 7-13. |
Here is a file from holl_ands for a channel 3 to 5 Log-Yagi that has two active elements and a parasitic reflector and directors. Note that the gain curve is fairly flat across the design bandwidth, as opposed to a Yagi that has a gain curve that rises from the low end to the high end.
http://imageevent.com/holl_ands/logy...0elch35logyagi This is the Antennacraft Y-10-2-6 Log-Yagi. The design is deficient for channel 2. http://imageevent.com/holl_ands/logyagi/y1026 |
I really appreciate all your suggestions and information.
Toying with the idea of producing antennas currently either hard or impossible to find new. There are several places in Phoenix that could make the components and a place here in Prescott that could assemble the components on the cheap. I just don't know if I want to undertake such an ambitious project at this time in my life..... |
Just the design and testing phase would be time consuming.
After you get all that nailed the rest is just building and shipping. Except for the after the sale customer service call headaches of course. lol |
Here is another online calculator, for designing a Log-Periodic-Dipole-Array.
https://hamwaves.com/lpda/en/index.html |
As always, there is good information here. Recently, a station that used to broadcast on RF 46 switched to RF 6 and now I find myself trying to figure out what to do. I've built probably close to a dozen or so UHF antennas, from M4's to a DBGH (currently on the house), but I've yet to try and tackle a L-VHF. Mainly because there has never been a need until now. I knew the station was going to make the switch, but I didn't care when it was only a religious station. But about a month before they switched, they added ION and Bounce to their line up and now I want to get it back. Has anyone as of yet tackled one of these monsters? If so, how did it work out for you?
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I have two commercially produced moderate to compact size antennas with L-VHF extensions here in SOCAL LA/OC. The RCA ANT3037XR (actually built by Winegard for RCA) and the Winegard HD7000R, one each for my two Samsungs, 2013 40" and 2017 32". There are several low powered stations on Mt. Wilson above LA, broadcasting on the L-VHF frequency right now and one full powered station, KWHY 22 (display, physical 4) at 35kW power (yes, that's right!) which carries Retro TV on KBEH 63-3. Since part of my TV viewing includes Retro programming, that was why I put up those antennas. Plus, there might be possibilities of other stations moving to L-VHF in the future or increasing their signal. Nothing firm at the moment, just chatter from the NET. I'm in a strong to moderate signal area, 35 miles south of Mt. Wilson, so I get excellent (100%) reception from KBEH which transmits off the KWHY 22 tower. So, yeah it's worked out well for me. I hope this helps answer your query. I know you mentioned you build your own TV antennas, so I can't really help you with that issue if that's what you were looking for. Anyway, all the best..... |
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Or if you need more gain, try a 3 element Yagi antenna. I expect you would get about 6 dB gain out of a 3 element Yagi as compared to a dipole. You can use this calculator for the measurements (note: measurements in meters) https://www.rfwireless-world.com/cal...alculator.html Or this one has measurements in feet and inches plus measurements for additional director elements if needed: http://www.wc7i.com/yagi_calculator.htm |
Thank you for the information guys. I do want to try and build one to see if I can pull it off. But my plans may be on hold until the spring. I am roughly 30 miles from the towers of the Altoona antenna farm in PA, but due to the mountains, all my signals are 2 edge. I'll give it a shot as soon as I can. Thank you again.
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Hi eggman.
What material would you like to use to build your channel 6 yagi? I did a design that uses 3/4” hardline from a CATV scrap pile for the elements. I’ll send you the dimensions if you have access to that material. I have also built a bidirectional V beam from simple wire. A full rhombic is another option. In hilly areas such as yours the location of the antenna makes a significant difference. I have seen antennas in the side yard on a 10’ pole work better than the roof. Goo goo gachoo. |
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https://www.rabbitears.info/repackch...=&lss=&status= https://www.rabbitears.info/market.p...=13929#station The strength of the WKBS signal at your location will determine what type of Channel 6 antenna you will need. On the plus side, VHF signals can make it over rough terrain better than UHF signals. On the minus side, the noise level from electrical interference is high on VHF-Low, requiring a stronger signal with sufficient SNR above the noise. Tower Guy is correct; try different locations for your DIY CH 6 antenna. I made some measurements of electrical noise on all three TV bands; it was highest on VHF-Low: https://i.imgur.com/aAU1EBY.png This is what the noise looks like on VHF-Low at my location. The signal had to be at least -8 dBmV (-57 dBm), which is a fairly strong OTA signal equivalent to 34 dB NM on a TVFool report, for reliable reception: https://i.imgur.com/DwQNtji.jpg Signal diagnostics: https://i.imgur.com/eiRXzRu.jpg Channel 3 folded dipole antenna: https://i.imgur.com/6qYVZsO.jpg |
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cambria county on AVS extended the rear elements on his RCA ANT751 to be able to receive WQED from Pittsburgh. It moved from 13 to 4.
https://www.avsforum.com/forum/45-lo...l#post58584134 Quote:
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Those elements are a little too long for channel 6; should be more like 33 or 34 inches on each side. This is what the Winegard HD7000R looks like with the VHF-Low extensions added: https://forum.tvfool.com/attachment....5&d=1572964727 https://forum.tvfool.com/attachment....6&d=1572966677 |
Another option would be to use an FM antenna, especially for
Rf 6. You cannot beat the price..... and it works very well for a 500 watt, Rf 6, translator at 20 miles away. https://www.newark.com/stellar-labs/...ING-Electrical |
That's a good idea.
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http://www.tvfool.com/?option=com_wr...90386ebd6201d7
My TVFool report. It's not very accurate as these are the old listings and the channel I'm trying to get isn't even on there BEFORE the switch. Actually, my NBC station used to come in on RF 34 which isn't on the report either. They switched to RF 35 around the same time and signal now cuts in and out. Maybe an LTE filter is needed? I don't know. I haven't had a chance to try anything yet. Hopefully over the weekend. I apologize as I just now have only had a chance to check the thread and am getting ready to run out the door to work. I'll look over everything everyone has posted ASAP. Thank you all. |
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