The 12x15 on the mast has been performing great I really like this model. I had a conversation with an engineer who ran it through the software. The only red flag was a high SWR at the top of the UHF band (33-36). To correct this and to maintain the strong lower frequency reception he suggested the bows be shortened to 11.5 inches. I haven't changed anything yet, I have more physical experiments to perform as I just can't envision waves jumbling up at the higher frequencies over a few channels. I need to calculate more.....
As a retired Radio and TV engineer in the UK, I find these US and Canadian antenna-building channels very interesting and I think yours is one of the best. I'm always looking for ideas for adapting them for other frequencies. In Western Europe the frequencies of UHF TV transmitters were planned in the early '60s when analogue TV began to expand from Hi-VHF (Band III, around 200 MHz) to UHF, I think West Germany was the first. This means that all of the channels in your area come from one site, so higher-gain antennas like Yagis and log-periodics are used and the transmitter power is lower, usually 100kW maximum for main stations. The bow-tie design is sometimes seen when a short wide-band antenna is required, but the Gray-Hoverman type is never seen. The Yagi antennas, normally used, have a narrower bandwidth, suitable for your local transmitter, rarely needing a bandwidth of more than 14 8-MHz wide channels (19 US 6-MHz channels). I think a single Bow-tie, mounted vertically, might be useful for Digital Radio which is transmitted here on the old European TV channels in the Hi-VHF Band.
Very interesting insight into the workings of the tv broadcasting system of the UK, interesting indeed. I do understand our systems operate differently, however, the radio waves are the same everywhere. Any of the antennas I present on my channel can easily be adapted to match the wavelength of a target frequency. The only limiting factors would be distance and terrain. With most of your towers clustered the yagi or log periodic are excellent choices. In the US towers are often scattered and bidirectional receiving antennas are required. It was great to have your input, it spurred me to do a little reading about UK broadcasting. Thanks for the compliment, much appreciated. I endeavor to present the information as clear as possible hopefully inspiring a new generation antenna users and hobbyist. Thanks Michael @ Cosmic
I built your 9x15. Finding something suitable for a reflector is my biggest problem. The wire fencing is expensive, and I just don't need a big roll. Since mine is in the attic, I used cardboard, double sided tape and aluminum foil. 🤣😂
Many people use the foil and cardboard trick for attic antennas, saved money and you actually get 100% reflectivity, something we can't do outside with the wind and weather. How is the antenna working out ?
@@cosmicantenna9244 I didn't get very good reception. I wonder if I did something wrong. I am trying to specifically target Fox 5 in Atlanta. I used stainless steel rods for drop ceilings for my whiskers, and 18 gauge copper for the connections. Gonna try moving it around the attic a bit too.
I've got to tell you, attics are not the best choice of location for reception. If your towers are close you should be ok. Mostly depends on the roofing material. Shingles manufactured in the last few years have a high zink content, they really block the signals. Moving around and testing is tedious, but it works. The stainless wire is a is a good conductor and should be fine. If you can't get it to work convert to a 4 bay, doubling the power of the antenna. I've seen pics of guys with 8 bay attic antennas that work fine. It's just a tough place to work.
@@cosmicantenna9244 Roger that. The handy wavelength website says 20.3 is the optimal wavelength for RF channel 32. Is that how long my folded whisker should be?
That would be correct 20.4 inches folded gives 10.2" or a half wave per side of the bowtie. When finished the total element length (full wavelength) would fit ch 32 right on the money.
Even more simplistic for people to build without the need to build extra insulator brackets.. will save time and patience
The 12x15 on the mast has been performing great I really like this model.
I had a conversation with an engineer who ran it through the software. The only red flag was a high SWR at the top of the UHF band (33-36).
To correct this and to maintain the strong lower frequency reception he suggested the bows be shortened to 11.5 inches.
I haven't changed anything yet, I have more physical experiments to perform as I just can't envision waves jumbling up at the higher frequencies over a few channels.
I need to calculate more.....
I like the saying if its free its for me. We must be thinking the same logic. Very nice Cosmic Antenna.
One very nice antenna and well built.
Thanks RG.
Been having terrible network issues lately and I posted this as a test.
@@cosmicantenna9244 Keep posting, you have a great design/antenna.
As a retired Radio and TV engineer in the UK, I find these US and
Canadian antenna-building channels very interesting and I think yours is
one of the best. I'm always looking for ideas for adapting them for
other frequencies. In Western Europe the frequencies of UHF TV
transmitters were planned in the early '60s when analogue TV began to
expand from Hi-VHF (Band III, around 200 MHz) to UHF, I think West
Germany was the first. This means that all of the channels in your area
come from one site, so higher-gain antennas like Yagis and log-periodics
are used and the transmitter power is lower, usually 100kW maximum for
main stations. The bow-tie design is sometimes seen when a short
wide-band antenna is required, but the Gray-Hoverman type is never seen.
The Yagi antennas, normally used, have a narrower bandwidth, suitable
for your local transmitter, rarely needing a bandwidth of more than 14
8-MHz wide channels (19 US 6-MHz channels). I think a single Bow-tie,
mounted vertically, might be useful for Digital Radio which is
transmitted here on the old European TV channels in the Hi-VHF Band.
Very interesting insight into the workings of the tv broadcasting system of the UK, interesting indeed. I do understand our systems operate differently, however, the radio waves are the same everywhere. Any of the antennas I present on my channel can easily be adapted to match the wavelength of a target frequency. The only limiting factors would be distance and terrain. With most of your towers clustered the yagi or log periodic are excellent choices. In the US towers are often scattered and bidirectional receiving antennas are required.
It was great to have your input, it spurred me to do a little reading about UK broadcasting.
Thanks for the compliment, much appreciated. I endeavor to present the information as clear as possible hopefully inspiring a new generation antenna users and hobbyist.
Thanks
Michael @ Cosmic
I think mr. Hodges originally started this build
Hodges builds a 4 bay Bowtie that he copied from mclapp years ago. I've never see a two bay 12" x 15" built by Danny.
Documented 2009
imageevent.com/holl_ands/multibay/4bay/superm4
My page
cosmic.simdif.com/page_2588862.html
I built your 9x15. Finding something suitable for a reflector is my biggest problem. The wire fencing is expensive, and I just don't need a big roll. Since mine is in the attic, I used cardboard, double sided tape and aluminum foil. 🤣😂
Many people use the foil and cardboard trick for attic antennas, saved money and you actually get 100% reflectivity, something we can't do outside with the wind and weather.
How is the antenna working out ?
@@cosmicantenna9244 I didn't get very good reception. I wonder if I did something wrong. I am trying to specifically target Fox 5 in Atlanta. I used stainless steel rods for drop ceilings for my whiskers, and 18 gauge copper for the connections. Gonna try moving it around the attic a bit too.
I've got to tell you, attics are not the best choice of location for reception. If your towers are close you should be ok.
Mostly depends on the roofing material. Shingles manufactured in the last few years have a high zink content, they really block the signals.
Moving around and testing is tedious, but it works.
The stainless wire is a is a good conductor and should be fine.
If you can't get it to work convert to a 4 bay, doubling the power of the antenna.
I've seen pics of guys with 8 bay attic antennas that work fine.
It's just a tough place to work.
@@cosmicantenna9244 Roger that. The handy wavelength website says 20.3 is the optimal wavelength for RF channel 32. Is that how long my folded whisker should be?
That would be correct 20.4 inches folded gives 10.2" or a half wave per side of the bowtie. When finished the total element length (full wavelength) would fit ch 32 right on the money.