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What FM antenna are you using!?

Damon Hill said:
What's the build quality like? I'm disappointed with my Antennacraft FM-6; between Fedex warping it in shipment and five years on the mast, it hasn't held up very well. I wouldn't mind having that Yaesu, either. My ancient Channel Master rotator from the early 80s isn't going to last forever.

--Damon, who misses his old pair of Finco FM-4Gs from the late 60s
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Here's a pic of one from the website that I bought it from:

3H-FM-92-shorted-Kit.jpg


The aerial partly assembled as I bought it:

3H-FM-92-shorted-assembled_b4.jpg


In fact, sKiZo's pic shows two vertical 9.2s on the mast. Mine has been up since last October and it has been through a couple of winter storms so far.

Regards,
Nick
 
Die Antenne wird in Einzelteilen, als Selbstbausatz geliefert!

(any US distributors?)

I ran into that whole import thing when trying to get a Sirio antenna a while back. Apparently one of the first to enter the states and it got held up for several weeks in customs while TSA frisked it for nucular dewices ...
 
Nick_G said:
Here's a pic of one from the website that I bought it from:

3H-FM-92-shorted-Kit.jpg
Click to expand...

'Tis a thing of beauty. Rotor is a must though, with any of these big Yagi/Directional antennas, right? In my case, if I wanted to pull in channels from two neighboring cities in different directions?
 
At home I have a Magnum Dynalab whip which I believe is made by Metz. Here in Los Angeles it works well, but I would not pay $200 for it. We also have a weekend place in the mountains and the only Fm I was able to get was the one local station. L.A. Stations are blocked, so I got some copper pipe and made a Jpole and added an amplifier and am picking up a low power station from the desert as well as San Diego and a couple from Las Vegas. I found the Jpole works very well for me.
I should add I am using a Sony HD tuner which is a great DX tuner which helps a lot.
 
jaymanaa said:
http://home.earthlink.net/~schultdw/antenna/PlainWireFancyReception.html
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figure2.gif


^ Would love to give this a try, but I'm not sure I can make sense of what they're suggesting. . . fig. 2 shows leaving one "arm" at 28 5/8" & shortening the other down to 23 1/2", but the article says, "If you already have a folded dipole antenna, modify it by shorting the wires in each arm, 23 1/2 inches from the center of the antenna." So, which are they suggesting?

Also if I don't plan on ever tuning past 89.7, their formula 5616/freq = ideal length would yield 5616/89 = ~63.1, which is, I believe, longer than most standard dipoles.
 
I believe they are showing a symmetrical antenna with the width to the inner part of the twisted end being 23.5" and the outer end of the twisted wire being 28.625". Doubling this dimension gives you the overall width of 57.25", so the antenna seems to be symmetrical.
 
I see!!! So it's not a matter of shortening the ends, but rather twisting a specific length at the ends? I was confused by their repeated use of the term "shorten".
 
for the time being i use a icom ah 7000 omni directional antenna for fm until i get a yagi.
 

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There are some serious antennas here. I live in a city and channels are well separated so I get away with an old model Terk FM+ (also sold as Radio Shack No. 15-1843).
 
I snagged a Dynalab SR-100 on Amazon for $45 shipped. I needed to grab SOMETHING that would get decent reception w/o needing to hang on the wall (WAF) & this does the job nicely pulling in my local stations as well as, or slightly better than, a basic dipole. Will continue to explore ideas for an outdoor or attic antenna to pull in the classical station in Sarasota. . .
 
sKiZo said:
Ever want to replace that RatShack rotor, they're apparently built by AntennaCraft. Got one of these a while back, and the motor is identical.

http://www.solidsignal.com/pview.asp?p=tdp2

My control DOES have the AntennaCraft logo and number on it ...
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It happened. The old one (2008) died -

index.php


index.php


Two days ago. Fortunately we're enjoying a warm spell and I replaced it with an even older (2001) backup (on the right) -

index.php


The older one would occasionally freeze up on cold (< 32 deg) days and I would have to wait until it warmed up again for it to free up. To reduce the risk of that happening with the replacement I sprayed WD-40 into the slight gap beneath the sliding rubber seal to keep water from wicking in and freezing. Good way to spend a record warm Christmas afternoon.
 
I just wrapped a couple layers of black tape around the edge of the bottom panel if I remember right.

Only complaint I'd have about the rotor is the brake isn't very strong ... or maybe that's a good thing. We had some serious winds over 60mph here a couple days ago, and the antenna spun some. No biggie ... turn the rotor fully clockwise to the stop, then counterclockwise to the stop, and it synchs back up with the inside control nicely. So far anyway.

100,000 people ended up without power for a couple or three days, so I guess I can't complain about having to play with the rotor, eh. They're just lucky the weather's been otherwise moderate.
 
loopstick said:
It happened. The old one (2008) died -

index.php


index.php


Two days ago. Fortunately we're enjoying a warm spell and I replaced it with an even older (2001) backup (on the right) -

index.php


The older one would occasionally freeze up on cold (< 32 deg) days and I would have to wait until it warmed up again for it to free up. To reduce the risk of that happening with the replacement I sprayed WD-40 into the slight gap beneath the sliding rubber seal to keep water from wicking in and freezing. Good way to spend a record warm Christmas afternoon.
Click to expand...


I have one of those it serves a two fold purpose. ; the first is for FM reception and secondarily for HD TV. My main concern is a low power college station playing Jazz and I am 23 miles past its fringe area. I have spoken with the Station Engineer and he was amazed I could get decent copy of the broadcast. He lives near me and has difficulty in hearing the station. I have received telephone calls to check on whether I received the broadcast or not with enough signal strength to cause the tuner to lock on a stereo signal. (I live outside the Los Angeles area and a few local college stations are quite strong which also makes hearing KJAZZ Signal Hill transmitter site a challenge at times), even Riverside stations which are almost as far away from me are usually easier to pick up than this desired jazz format broadcaster. The metro stations are so strong I can get those with a simple wire and often don't need even a common twin lead dipole for them.

An issue that happens from time to time due to propagation is affecting the signal is it will be better to use a vertical even though the gain is much less than the yagi (TV/FM) antenna causing the tuner to be unable to lock onto the signal sufficiently to produce a solid stereo playback. I grew tired of trying to rig up a switch box for the F connector and having tried to couple or co-phase the vertical and horizontal yagi since it actually resulted in either increased multi-path or signal strength reduction I opted to keep just the yagi up and zeroed it onto the best direction for that one station. I have used various pre-amps and signal boosters as well.. Some work better than others with the basic older metal AC powered device serving as the best units overall.

If you look around these are fairly easy to spot and usually have some "ears" to mount them onto a wall or cabinet. If you can find an adjustable model it will work best since you can then dial in exactly the necessary amount of gain or boost for your tuner/receiver. I prefer to use 75 ohm quad shield RG-6 coax similar to that of cable TV or the small dish providers.

In closing I find folks who use a J-pole antenna make claims that it is far superior to an omni-directional vertical and how poorly the small active antennas are when in fact the J-pole is nothing more than a 1/4 wave omni vertical unamplified antenna period. It may serve your needs but it is just another variation of a omni vertical and please try to remember this, one is amplified and the J-pole is not. Basically the same antenna just a different example. Some use a matching coil some use a matching stub. They are simply the same type of antenna.

One factor folks are aware of but seldom mention is that FM broadcasters all use vertical tower/antennas to send their programming out so common sense would seem to dictate vertical source vertical reception. this is not always the best solution due to the changes a signal can experience once into the atmosphere.

Thanks for reading.

Hermit
 
The towers may be vertical but usually the polarization is right-hand circular. That way, the signal can be received by vertical or horizontal antennas and circularly polarized antennas, but the polarization direction may reverse due to reflections, so a right-hand polarized antenna used to receive a right-hand polarized signal may get nothing from a reflection. Someone with more antenna knowledge should reply here as to whether a circularly polarized antenna can eliminate multipath reflections or do reflections just degrade the signal.
 
Interesting site for antenna nerds:

The KEN JONES Memorial Picture Index WIKI

Not every state is covered but you may find some pix of antennas of local broadcasters. Here are pix of the antennas of three local college FM stations. The antennas aren't circular but maybe they spin the phasing to get a rotating wavefront. Dunno. Any news on JBL Guy?

witr-2.jpg


wber-2.jpg


wrur-5.jpg


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