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Old 2012-05-07, 05:49 PM   #106
jpasadena
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Default Single lead from radio to folded dipole

My daughter's Sony clock-radio-CD-player has a single wire coming out the back for an FM antenna. We are in a poor reception area and I can easily build a folded dipole with balun. Question is: how to attach the two leads of the balun to a radio with only one antenna wire?
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Old 2012-05-07, 09:02 PM   #107
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Default An FM Antenna Choice

Hello Everyone:

I'm not sure if this is the right area to put this question, so if it's better asked in another place, let me know. But seeing as this is the Antenna Forum, it seemed worth a shot.

If you've been following my progress in the Barrie OTA Reception Reports thread, you'll know that I'm putting up a tower in the next few months to improve my TV, FM and Ham Radio. The Ham radio antenna is easy...a Cushcraft MA5B 5 band minibeam (lots of coverage, good signal, and very small footprint). The TV antenna is pretty much set too...an Antenna Direct 91XG, which has been giving me pretty good signals since I put it on my roof a few months back. When the tower is built, the whole lot of it will be on a DMX68 self-standing tower, about 75 feet up...so I'm hoping for somewhat improved reception.

http://www.eham.net/reviews/detail/3...02e9ec45f0b8e2

http://www.antennasdirect.com/store/...V_Antenna.html

Now here's the problem. What about FM? Right now I'm using a Winegard HD8200 from Save and Replay for VHF-TV and FM together. It works pretty well, but the tower builders (Kelly's TV Towers in Barrie) informed me a dedicated FM antenna would work much better than a Combo VHF-UHF-FM antenna such as the Winegard HD8200U. Is this in fact correct? How much of a difference will a dedicated antenna for FM make? I mean, look at the gain and forward/back ratios for my antenna, the Winegard HD8200, and an FM only dedicated Winegard HD6065P (8 element FM only aerial)

The Winegard HD8200 Combo gain is 6 db to 10.4 db on Channels 6-7 (the FM band of course lies between channels 6-7), so I'm supposing an average gain of about 8 db or so. Forward to back ratio is 17 db to 20 db (say 18 on average?)

The Winegard HD6065 Dedicated FM antenna has a gain of 8 db over a reference dipole, and a forward/back ratio of 19dB. Ie, they look pretty much the same. But the Dedicated FM antenna has 8 elements, and the Combo antenna has only one or two for the FM region of low VHF! So surely an 8 element would work much better. So why don't the published figures show this. Am I missing something?

http://www.winegard.com/kbase/upload/HD8200U.pdf

http://www.winegard.com/kbase/upload/HD6055P.pdf

Are there any other options? I believe the very best FM antenna ever made for home use was the monster APS-13, but it is no longer being produced. Are there any other equivalent options available now, here in Canada? Thank you for your ideas; this place has been very helpful in all things Radio/TV!

VA3SAJ
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Old 2012-05-07, 10:12 PM   #108
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If a VHF/UHF Combo antenna manufacturer "forgets" to provide an FM Gain spec
number, it is very likely the antenna is NOT designed for the FM Band, such as
is shown in the "Raw gain for some common VHF antennas" chart for the
W-G YA-1026 ("C" line) and R-S VU-90 (brown "L" line) antennas:
http://www.hdtvprimer.com/ANTENNAS/comparing.html

Note that CM-3671 had highest FM Gain (not quite 5 dBd) among the modeled
VHF/UHF Combo antennas....which MIGHT be very close to W-G HD8200
(which was NOT modeled here and does NOT specify Gain in the FM Band).


Unfortunately, some Combo manu's, such as Antennacraft, only indicate
a Gain spec for the VHF Band (Ch2-6+FM)...which MIGHT be average,
minimum or (more likely) maximum (for the "best" freq. in the band),
making it impossible to determine Gain in the FM Band.

For a Multi-Band Combo antenna, the number of VHF-ONLY elements
might be a good indicator of relative VHF performance....but may or
may NOT indicate relative FM performance, depending on whether the
manufacturer intended to provide good FM performance....or whether
the engineers were trying for the best Ch2-6 TV performance and were
satisfied to accept whatever Gain remained in the 20 MHz wide FM Band.

And, of course, in an FM-ONLY antenna, ALL of the elements are dedicated
to enhancing Gain in that band, rather than being spread thin trying to
provide Gain over all BOTH Ch2-6 and FM Band.

K6STI (Brian Beezley) modeled performance for many FM antennas, with
dimensions available in the EZNEC file if you want to build your own:
http://ham-radio.com/k6sti/curves.htm
http://ham-radio.com/k6sti

The fol. website summarizes manu. specs for many FM Antennas:
http://www.fmtunerinfo.com/antennas.html

And here is an even better website, which was recently updated:
http://www.aphenos.net/electronics/s...g_Antennas.htm

You will find that most of these FM antennas are no longer in production.
Also be careful whether specs are in dBd or dBi, where dBi = dBd + 2.15 dB.

W-G HD6065P may be highest (7-8.6 dBd) Gain for readily available FM Antennas.

====================================================
BTW: Weak Ch7-13 TV reception can be blocked when strong FM signals are
passed through a common Preamp due to Second Order Harmonic of FM signals.
Third Order Intermod products between FM signals can also degrade Ch5 & Ch6.
Hence it is best to use a separate coax downlead (and optional Preamp) for FM,
esp. since they tend to be scattered around the countryside, vice on mountain tops.
This might also reduce loss by about 1 dB due to elimination of band separators.
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Old 2012-05-07, 11:41 PM   #109
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With the exception of the limited Winegard line, high gain consumer FM antennas have completely disappeared off the market.

This may still be available; looks like an old Finco FM-5:

http://www.magnumdynalab.com/fmantenna-md10.htm

Professional grade CATV-type FM antennas are available from the likes of Scala and others, but expect to pay well north of $500 for a rugged design that'll only slightly outperform the Winegard.

If you've got to have lots of gain/directivity, you'll have to roll your own. Brian Beezely's site is a very good place to start for examples of designs.
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Old 2012-05-08, 12:50 AM   #110
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Magnum Dynalab MD-10 appears to be a 10-El. Log-Yagi (8 Driven Elements) with
142-in Boom, providing 12 dB (prob. dBi, hence 9.9 dBd) of Gain & 15 dB F/B Ratio.

It's about as "readily available" as W-G, C-M, etc, via on-line order and dealers
throughout US, Canada and elsewhere:
http://www.magnumdynalab.com/dealers.htm

BTW: Finco FM-5 had 10 Elements...on shorter 120-in Boom....and only 3 were driven....

PS: EV's FM & HD Radio Antenna thread is very extensive....but barely mentions
the Magnum Dynalab antennas in post #76:
http://www.dtvusaforum.com/dtv-hdtv-...reviews-4.html
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Old 2012-05-09, 08:57 PM   #111
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Hi Guys:

Thanks very much to holl ands and Damon Hill. Holl ands: I tend to agree with your analysis, all the elements of an FM antenna are designed specifically for that band, so it is likely going to be a better performer. The Winegard HD6065 is available at Save and Replay, but not the Magnum Dynalab MD-10, which Damon Hill mentions. But there is a Mississauga Outlet of Magnum Dynalab that can provide that 10-element MD-10 antenna. I recently went there to purchase an MD-205 FM Signal Sleuth, which works pretty well on some of my FM receivers, but doesn't really add all that much to my Sony XDR-F1HD, which is already pretty sensitive, LOL! But at the time I was there, they mentioned they could get in an MD-10, if I wanted one. I'm still thinking through all the options.

Ultimately, I guess we could wonder/speculate forever...the only way we're really gonna know is haul all that iron into the sky and try it out. So I think what I'll do is put the Winegard HD8200U I already have on my roof up the tower for a few weeks and see for myself. If it works better, great. Then I can haul up an 8 or 10-element FM only antenna and see how much difference it makes (if any). There may well be a point of diminishing returns here anyway. I mean I have an extreme fringe antenna on a huge DMX tower connected up to an ultrasensitive receiver...there may be "Ne Plus Ultra" going on, maybe I've pretty much maxxed out all I can do here.

Thanks for all the suggestions...I'll try them out, and get back to you.

VA3SAJ
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Old 2012-05-10, 01:35 PM   #112
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That's pretty great that you can still get a WG 6065... They've been gone for years now, with no real replacement in its price range. Your source probably has one of the few new ones left on planet Earth.

I've used one for years along with the Sony XDR you have (and some older sensitive tuners before the Sony was introduced) and it's pretty great.

One thing you could consider, if you have some favorite stations in a narrower band, is making your own. I started a thread on that here:

http://www.digitalhome.ca/forum/showthread.php?t=144594

I admit I never built the ones modeled here because I was able to get the 6065 back into decent enough shape after a storm mangled it. Never thought I would, but after many careful days plus a lot zip ties and metal screws, I got it mostly back in one piece. Still looks pretty bad, but it seems to be working okay.

One reason I did this is I found another DX station I like at 94.7, which is well below the range of the ones other members here so generously modeled for me. If not for that, I'd have built one, because it would have even higher performance and would be a lot smaller. The 6065 is a pretty big beast.
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Old 2012-05-14, 07:47 AM   #113
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That single wire is likely acting like a monopole, which are unbalanced and typically have a characteristic impedance of 75 ohms. A folded dipole is balanced and has a characteristic impedance of 300ohms, so you are on the right track using a balun. You could try connecting only the centre conductor, but that likely isn't going to work well. A second option would be to open up the radio, find a ground point and connect the shield to that (potentially even putting the balun inside the radio), but that might not be safe. Another option would be to buy an FM monopole antenna (like a car antenna) and use that instead.
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Old 2012-05-14, 09:31 AM   #114
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I would open the radio and find the RF front end, and put an F connector on that (signal and ground), or hard wire a matching transformer.
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Old 2012-05-27, 05:28 PM   #115
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Hi Choclab (and others):

I got a Winegard HD6055P, not a 6065...SaveandReplay is no longer carrying them, and replacing them with the 6055 instead, my error. That's quite a loss, as you noted, as the 6065 has 10 elements, the 6055 only 8. That being said, the 6055P works very well on the top of my tower, giving good listenable audio from Toronto, Buffalo and even Rochester FM channels (thats on a regular basis, not tropo). I even get an HD lock on several Buffalo channels up here in Barrie with it.

http://www.winegard.com/kbase/upload/HD6055P.pdf

Holl_ands/Damon Hill:

I just called the Magnum Dynalab people in Mississauga, they sold me their famous FM signal sleuth, which certainly helps on some of my FM tuners (but I think my Sony XDR-F1HD is already pretty much maxxed out in terms on sensitivity/selectivity, so I didn't notice much of an improvement on it). They said they are no longer carrying their FM DX antenna, the MD-10, so that's another choice gone:

http://www.magnumdynalab.com/fmantenna-md10.htm

I love the aphenos website, I've used it before to compare HDTV and Combo antennas:

http://www.aphenos.net/electronics/s...g_Antennas.htm

Based on that website, the "Ultimate" FM antenna would have to be the now-discontinued APS-13, 200 inches long, 13 elements, with a gain of 10 dB, and a F/B ratio of 30! But I haven't seen one of those for sale for many years.

However...I have found a rather interesting English aerial-maker who doesn't appear on any of the charts I've seen so far, either here on the Digital Forums or elsewhere. Ron Smith Aerials of Luton, UK, make high gain FM antennas that literally knock your socks off, if their figures are to be believed. I wonder if the folks in the antennas subforum of this website have had a look at modifying these antennas for DTV as they'd likely be capable of miraculous things. Have a look at this baby:

http://ronsmithaerials.com/catalogue/G23.php

23 elements, 134 inches long, it has an alleged gain of 19 dB and a F/B ratio of 38.9 dB!!! That would literally blow everything on the aphenos website out of the sky, if it is true. Has anyone had any experience with these things? They can apparently be ordered for 290 Euros and can be shipped to the Americas, though the details on this I do not yet have. Other models have suitable astonishing gain and F/B figures, here:

http://ronsmithaerials.com/catalogue...IDE/PAGE9.html

The ultimate appears to be a Galaxie 32 (special custom order only, price who knows?) 20 feet long, 32 elements, gain 21.2 dB.

http://ronsmithaerials.com/catalogue/fm.html

What do the people here think? Can this be true? Or am I reading their figures incorrectly?

VA3SAJ

Last edited by va3saj; 2012-05-27 at 05:51 PM.
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Old 2012-05-27, 06:02 PM   #116
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Quote:
Can this be true? Or am I reading their figures incorrectly?
The Galaxy 23 has 4 sets of directors and a corner reflector that is on the small side for its driven element. I would generously estimate it to be around 15 dBi, not 19.2 dBi. Still a very very powerful FM antenna. It should pick up anything that can be picked up in the FM band.

Note the comment from 1981, before computer modeling. Back then, quite a few manufacturers were testing under unusual ground conditions to exaggerate the gain figures.
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Old 2012-05-27, 11:22 PM   #117
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Still the Galaxie 32 is a serious Dreamweaver as far as I'm concerned. But as things stand, I currently own a 6055P bought in 2008 and am ordering a second one that i'm planning on taking to the Gaspe coast in late June ripe for the Es peak season. I have used stacked 10-elements in the 90s and for what lies around today, the 6055 still provides plenty of enjoyement!
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Old 2012-05-28, 07:16 AM   #118
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Quote:
Going digital with a pair of CM4228a pointing due south fed into a Winegard SD-3700 antenna coupler @220 ft
I still haven't tested my SD-3700, but a member here has with some pretty fancy equipment. It seems the SD-3700 has some pretty large losses at uhf frequencies, so you may be better off with a two balun and splitter used in reverse type setup.

However, the SD-3700 has only tiny loss at vhf-low frequencies, so it would be an excellent choice to couple the two 6055P's.
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Old 2012-07-25, 09:26 AM   #119
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Anybody ever try the Pixel AFHD-4?

http://www.pixelsatradio.com/product...tenna-combo-2/

Just wondering if this will perform ok with a standard, consumer grade AM/FM stereo receiver. Thanks for any input!
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Old 2012-07-25, 10:16 AM   #120
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^^^Looks to me like a car radio antenna with a mounting bracket, F connector adapter, an AM/FM band separator, an AM Balun and some other bits and pieces. It will be a low gain antenna and thus should be fine with with a "standard, consumer grade AM/FM stereo receiver" but it seems a bit expensive for what you are getting. Alternately, you could buy a car antenna (possibly from an auto wrecker), the AF-KIT (if you also want AM) and make a bracket and F adapter.

The Installation Instructions are an interesting read.
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