Hello All! I recently purchased an old analog AM/FM Multiplexing stereo receiver from Goodwill. With all luck it works and looks fantastic. So started my quest to build an antenna to compliment my receiver. First off, I want to build vs. buy because I love to build, refurbish and repurpose stuff. What I do know about FM antennas is the height is important for receiving distant signals, which would be one of my objectives along with signal clarity. So I have decided to mount whatever antenna I end up choosing on a 20 to 25' mast. Antenna jargon, theory and what differentiates one to another is beyond me at this point. I don't want to build a directional, but rather an Omni FM wideband. I have experience with electronics and components but nothing associated with RF. Something on the elaborate side doesn't intimidate me because half the enjoyment will be in the project itself. If anyone has the time to suggest an antenna(s) with plans I would be very appreciative. There is a LOT more to antenna theory and application than I ever would have realized. And if it matters I also purchased (from Goodwill) a Channel Master, UHF/VHF/FM, 263b antenna amp. I couldn't find a manual or instructions, or specs. but I do have it to add to the project. Thanks!
Newbie; Help with Omni FM wideband
- Thread starter gudbrand
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majoco
Stirrer
Hmm. About the only thing I have in mind is stacked FM dipoles and a phasing harness. Arrange the four dipoles on each cardinal point around your pole. You will get the advantage of a tuned antenna which you wouldn't get with a discone.
Here's a forum post on the same subject - you'll have to recalculate everything for 95MHz.
http://forums.radioreference.com/sc...155082-hme-brewed-4-bay-uhf-dipole-array.html
and here's a real one from prcguy just two entries down the page...
http://forums.radioreference.com/build-your-own-antenna/109144-4-bay-vhf-dipole-array-project.html
Here's a forum post on the same subject - you'll have to recalculate everything for 95MHz.
http://forums.radioreference.com/sc...155082-hme-brewed-4-bay-uhf-dipole-array.html
and here's a real one from prcguy just two entries down the page...
http://forums.radioreference.com/build-your-own-antenna/109144-4-bay-vhf-dipole-array-project.html
prcguy
Member
I think a phased dipole array is a bit much for a newbe without any test equipment to verify dipole resonance and cable lengths, but it would probably work great. I would start off with a simple 1/4 wave ground plane or even a J-pole, although I'm not a fan of J-poles.
You would have to use a fairly thick element to get 20MHz bandwidth at 100MHz for a ground plane or you could make the vertical element out of wire and loop in back down from the 1/4 wavelength end to the connector and ground it making a folded monopole. These have a little more BW than a simple 1/4 wave element.
Then there is a pair of crossed dipoles fed with a critical length of coax between them used as a power splitter and phasing line and you could use 3/4" copper pipe for the elements and a PVC pipe cross and Tee to hold the elements similar to the 4-bay dipole project in the previous post.
Most other types of antennas would need an antenna analyzer to make sure its tuned in the FM broadcast band unless you can find a specific project for the FM band and copy it.
prcguy
You would have to use a fairly thick element to get 20MHz bandwidth at 100MHz for a ground plane or you could make the vertical element out of wire and loop in back down from the 1/4 wavelength end to the connector and ground it making a folded monopole. These have a little more BW than a simple 1/4 wave element.
Then there is a pair of crossed dipoles fed with a critical length of coax between them used as a power splitter and phasing line and you could use 3/4" copper pipe for the elements and a PVC pipe cross and Tee to hold the elements similar to the 4-bay dipole project in the previous post.
Most other types of antennas would need an antenna analyzer to make sure its tuned in the FM broadcast band unless you can find a specific project for the FM band and copy it.
prcguy
Hmmm since im still struggling to understand the differences in antenna types Im not sure I follow you entirely on your descriptions. I Pretty much need a plan to go by. I have found 2 other possibilities as well. How would you rate either of these vs. the antennas you and Majoco have suggested? I just want to build the Omni FM antenna that will give me the greatest signal strength at distance, without the use of an antenna amp. I want to see how good the antenna will do before I decide to use my antenna amp if at all.
Wideband Vertical Omni, bowtie dipole; Wideband Vertical Omni
large FM loop;
https://fmdxing.wordpress.com/2014/07/09/simple-diy-fm-antennas-build-an-fm-loop-for-about-20/
Wideband Vertical Omni, bowtie dipole; Wideband Vertical Omni
large FM loop;
https://fmdxing.wordpress.com/2014/07/09/simple-diy-fm-antennas-build-an-fm-loop-for-about-20/
doublescan
Member
The FM Loop antenna is directional, according to the details. Makes me want to build one though! I prefer to build my scanner antennas and purchase the FM-ones, using an FM6 antennacraft right now and works quite well, but it is a directional antenna also.
As long as I can mount a directional and fit it in the rafters of my garage I could make an attachment to manually rotate.
I decided to build the VHF 4 bay dipole array. I calculated the phasing harness(s) I just need to know the calculation for determining the element length and spacing for center band FM. Majoco suggested 95 Mhz but for my antenna educational purpose why would it not be 98 Mhz?
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