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Teflon on antenna for deicing purposes

M

menotti1

Guest
i have heard of using teflon on ship antenna's for protection against corrosion,but never as an effective de-icing agent.another eng mentioned this to a friend of mine who has a 6 bay SWR that i feel needs de-icers...this eng told
him a teflon coating would guard against icing on the antenna.this install is in colorado so you know what the weather can be like there.height is 100 meters above ground.anyone heard of this teflon fix before? it's a first for me.but all of my installs have been in the lovely south...thanks for your input
 
We had a Jampro knockoiff of the G-5 for a while, which had a teflon coating. Didn't work worth a damn. Over a fairly short time, sun and pollution roughed up the surface. Wather stuck and froze, it was an ice hog. We replaced it with an identical model with deicers in. And, quickly as [ossible, put up a G-5 on a teller tower.. also with deicers in. Here in the South, you see more ice accretion due to freeze - thaw than you will in the north.
 
Thanks Littlejohn.i think that other eng may sell snake oil on the side.ha..your experience supports my theory on that.Gonna be hard to beat those radomes.I can't believe Bernie at Energy-Onix did not ask about radomes before selling that 6 bay SWR to my friend, talked about everything but radomes.But if you mount this antenna without them BIG trouble will be coming to see you soon...7900 ft amsl and a 300 foot stick, GEE you would just think this antenna will need de-icers..
 
Besides the icing problem, the biggest issue is: it's an SWR antenna. After they spend many $$$ trying to make it work they'll wish they hadn't gone low bid on the antenna.
 
that is so true.I LOVE ERI .that's the only one i've ever used.but i know some folks like the Jampro,dielectric,shively and other brands and that's ok.I replaced a SWR with a ERI, difference in coverage was amazing.you know the saying good ain't cheap and cheap ain't good.applies to antenna's too.
 
I'm a big fan of ERI when it comes to full power roto-tiller type antennas, but here in Channel 6 land, where vertical only rules the 88-92 band, the SWR & PSI antennas do a remarkable job and they are dirt cheap. I've never tried a circular one so I'll defer to my colleague's commentary on them.
 
menotti1 said:
that is so true.I LOVE ERI .that's the only one i've ever used.but i know some folks like the Jampro,dielectric,shively and other brands and that's ok.I replaced a SWR with a ERI, difference in coverage was amazing.you know the saying good ain't cheap and cheap ain't good.applies to antenna's too.
Click to expand...

One of my former stations had a Shivley on the main and an ERI on the aux....maybe 1/2 mile between them and the main was at 1450ft while the aux was at 1000ft...both using CEC 816R transmitters and both 100kw ERP.....when I tuned the aux on from 50 miles south, the main was TOTALLY covered up.....same if I was on the north side, etc...the ERI beat the Shivley so much...I will say Shivley can do great in directional modeling and pattern projection on side mountings..but then again, if an ant took a cold leak on the Shivley, the SWR was shooting skyward...where an ERI can take 1 or more inches of ice with NO change in reflected...the main antenna was installed under former management who LOVED Shivley.....I on the other hand have never been impressed with them.

Also 96.7 in the Dallas area (a class C rimshot) tried several antennas...when it went from a Jampro knockoff to an ERI to a Shivley, you could tell in Dallas metro what antenna they were using...the ERI was best overall; the Shivley was horrible!
 
Let me also suggest, the best money you'll spend on an antenna is the range fee for optimizing it to >your< tower and situation. It amazes me to watch someone spend beucoup bux on the latest Blastmaster Special and then have the rigger put it "wherever's convenient". The electric bill goes for heating the tower and the sky, instead of the listener's antenna. And the owner crabs about the "Lousy Blastmaster that doesn't work for beans."
A buddy took a snapshot on a 2000 footer of a side mounted FM. The top bay was maybe 8 or 10 inches from the guy which attached directly above the array. So, the rigger (who had mounted the thing where he was told) took a couple of rolls of black tape and taped the guy for a couple of feet to keep the thing from arcing and damaging the wire. I gave the manufacturer a print of the picture at a convention. His comment was "Well, now we know why that gent was b---ing about the coverage pattern."
 
Any recommendations for a non-pressured two-bay circularly polarized for an LPFM. The Jampro is out of the budget range. The facility is on a ridge, so a two-bay is important to throw the signal more horizontally.
 
Shively 6812 .great choice for LPFM.Contact them directly,they may have a slighly used one that you could get a deal on...
 
Antennas are a funny thing, like cars. You find the Chevy guys always buying Chevys , the Ford guys always buying Fords. Now both are good vehicles, but personal preference DOES make a difference.

Personally, from all my research into antenna systems and the signal propogations there of, I find I have to laugh at the comparison of two different transmitter sites and comparing the signals. The only real way to tell the difference between the radiating quality of one brand versus another is to put them both on the same tower, same age, with the same grounding level, mounted exactly the same, and on a purely flat surface. I am of the belief that if you stick with the big brand names such as Shively, ERI, Dielectric, and Jampro, you really can't go wrong. So much about a bad installation has more to do with improper design by the engineer , improper installation by the tower crew, and bad planning all around. A "side mount" antenna, no matter what the brand, on a 8' face tower is NOT going to radiate 360° , you are going to have some directionality. That's just common knowledge. I've heard some outstanding signals eminate from both Shively's and ERI's. I've also heard some lousy ones too. And I've heard some horror stories about BOTH companies as well...

As a personal preference, I have always liked the Shively antennas. I think they have made some big strides in their antenna design in 10 years, and the old "VSWR happy" designs of years back are gone. I've seen a lot of new Shively installations that are really a lot more stable and robust than "days gone by".

I remember reading somewhere that in the US, the antenna ranks (in regards to # of installations, translators excluded are, #1 ERI, #2 Shively #3 Jampro, #4 Dielectric, #5 Alan Dick). I think if you were to include translators, Scala would outnumber the rest. (With all the translators using Scala).

For LPFM, or a low power, the Shively 6812 is good, so isn't the Armstrong FMA707 and the NiCom BKG77.
 
I had an ERI 6 bay on the same tower as a DiElectric six bay. Reasults in iocing - the ERI stayed on, the DiElectric quit. Both electrically deiced. Trouble is, the feed point on the DiElectric (And the Shiveley) are exposed, and can't be heated. The ERI has everything inside where it's toasty warm.

And, in reverse sequence:

Mazda
Dodge
Volkswagen
Volkswagen
Chev
Buick
Ford

I recommend buying them - antennae and automobiles - for the purpose intended, rather than for whatever name is printed on the front.
 
I'd rather spend the money on radomes. Deicers are nice until lightning takes them out or the controller sticks causing them to run continuously shooting up the power bill. Transmitters less than 20 years old will reduce power to protect the antenna system anyway, so you're not off the air.
 
Here, I've had ice turn my radomed antenna into enough reactance to shut the transmitter down. ERI and Shiveley. On the de - iced one, it's 35 miles out of town... ten percent don't make the program. It's also a combined system - it is recommended that you >not< try to run an automatic foldback on a combined plant unless you want to derive the reflected sample ahead of the hybrid... which sample system you'll have to build yourself. Two thermostats are sufficient to control a deicer, and while it will run in sunny but cold weather, this won't hurt anything. Thermostats are frighteningly reliable. Experience here shows that the little power used is not a concern on the bill. It's probably about the same as airconditioner load difference summer to winter in a closed plant.
Now, the above addresses itself to major market stations. In small market, where we were the only game in format and often the only game in town, we skipped the deicers and the radomes, they weren't cost effective. Neither was a generator. Substantial savings there.
 
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