Antenna Build Suggestions - FM Radio - Canadian TV, Computing and Home Theatre Forums
 
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post #1 of 3 (permalink) Old 2018-06-06, 02:19 PM Thread Starter
 
Join Date: Dec 2008
Location: Bruce County, ON
Posts: 1,251
Antenna Build Suggestions - FM Radio

I'm looking for some suggestions to help build/assemble an appropriate FM antenna.

I've been using a CM 4228 UHF TV antenna clone for FM signals, but recently improved my TV signals by utilizing an FM trap. The antenna was OK for the most part for FM, with challenges picking up Toronto channels occasionally.

My goal is to get a reliable signal for CKFM 99.9 Toronto.

FM Fool:

FM Fool - FM Signal Locater

As of today, I'm getting an OK signal with a combination of an old RCA signal amplifier and homemade antenna (basically a long 16 gauge copper wire), however, just looking for suggestions on specialty FM antenna gear that anyone has experience with.

I would be looking for outdoor equipment suggestions that I would mount about 25ft. in the air on my TV mast. Worst case I would replicate my TV setup for radio.
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post #2 of 3 (permalink) Old 2018-06-06, 07:43 PM
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you could make a simple folded dipole from 1/2" copper plumbing for the FM band.
holl_ands has some pictures on his site, assembling one of his for vhf high.
A couple years ago I had used a simple dipole to receive CFTO from the CN tower all summer long
here just south of Buffalo. I thought that was pretty impressive.


https://imageevent.com/holl_ands/loo...5z8lnic2.dog_s

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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post #3 of 3 (permalink) Old 2018-06-07, 02:35 AM
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Your FMFool link is incorrect...you need to click on "save image" and then "save Image" to your HDD...and then post THAT Image....such as via "CP" to User Image Gallery.

Using one of the Post Codes for Ft Erie, ON, I can see that there are stations in nearly every direction, except far fewer in SW Quadrant....typical for most FMFool Reports I've seen.....NOT concentrated in a few locations like TV. IF you used a Directional Antenna, you MIGHT need to change it nearly every time you changed stations. [RF A/B Switch to select OMNI or Directional Antenna would be best of both types.]

When you post your FMFool, note that the couple dozen FM Stations in the "Green" Zone, "should" be receivable with an Indoor Antenna....such as simple Rabbit-ears or Twin-Lead Folded Dipole.

You might also be interested in Indoor/Outdoor AM Antennas listed here (such as for AM HD), in addition to Indoor/Outdoor FM Antenna alternatives:
http://www.digitalhome.ca/forum/26-a...ml#post2922681 [See also Post#12.]

==================================
FM Sensitivity Calculation:
Better FM Tuners provide a "barely acceptable" STEREO signal (50 dB SNR is well above typ. 70-80 dB SNR Floor) with about 15 uV (75-ohm) = 35.0 dBf = -85 dbm. And MONO with about 15-20 dB lower Signal Levels, depending on how poor a SNR you might want to tolerate:
Tuner Information Center - Specs Database

==================================
So for a TRUE OMNI with about 2.1 dBi (0 dBd) Gain Outdoors, it should be able to theoretically receive ALL of the FM Stations in your very long FMFool Report....and MORE....although a Directional Antenna on a Rotator would be needed to sort out multiple stations on the same (co-channel) or adjacent channels. And do NOT pass FM Signals through a Preamp...it will severely degrade reception.

I do NOT recommend trying to share TV Downlead with FM Antenna....use a separate Downlead to keep extremely strong FM Signals (need to see your FMFool) completely separate from TV Signals. You should also use a FULL-BAND FM Filter [e.g. Antenna Direct or Tin Lee) prior to TV Preamp/Distro Amp (if used)....also if only Tuner. Separate Downleads also avoids loss in FM/TV Combiner & Splitters....the cost of which can be applied against the cost of an FM Only Downlead.

==================================
Fol. Webpage summarizes performance for numerous alternative OMNI or Quasi-OMNI....and also some that CLAIM to be "Omni" but are actually Bi-Directional with Nulls towards the "sides", such as a simple Folded Dipole...and many so-called "FM Turnstiles":
https://imageevent.com/holl_ands/omni

Many FM Stations broadcast in Circular Polarization (Horiz = Vert.), and many broadcast Elliptical Polarization (Horiz stronger than Vert.) and many still broadcast Horizontally Polarization only. Hence, unless you want to build a DIY Circular Polarized Antenna, your best Antenna choice would be Horizontally Polarized. As is clear from the comparison chart, the Double-Hoop, would be my first recommendation for an Outdoor or Attic Quasi-Omni Antenna:
https://imageevent.com/holl_ands/omni/doublehoop

Fol. Double Hoop AM Antennas are inexpensive and Commercially available:
https://www.amazon.com/dp/B00DHHOZBI
https://www.amazon.com/ViewTV-VT-FM1.../dp/B01M4OCNXR

And for 6 dB higher OMNI Gain (and better SWR), I'm still hoping someone will want to try fol. 16-ft TALL DIY Swept SBGH project:
https://imageevent.com/holl_ands/omn...tsweptsbghomni

And if you want to try a directional FM Antenna, nearly ANY Antenna (e.g. Hi-VHF Band) can be Rescaled to FM Band my making ALL Dimensions Larger by the Rescale Factor = F = 216/110 = 1.96 (OK to round up to 2.0)....take your pick following below Imageevent link, such as one o the fol. YAGIs:
https://imageevent.com/holl_ands/yagis

Or make a Clone of one of these:
http://ham-radio.com/k6sti

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands

Last edited by holl_ands; 2018-06-07 at 04:02 AM.
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