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FROZEN OVER ANTENNA?

Sonar

Sonar

Sr. Member
Apr 8, 2016
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It's been approximately 5 weeks since I've fired up the station.
With 23 degrees and an 8 degree wind chill here in New Jersey I decided it would be a good day to fire up the tubes and stay warm while enjoying a qso or two.
I started off with the amplifier in standby (thank goodness,) and the wattmeter in the 0-20 range (which I never do but because of the 5-week shut down, decided it might be a good idea.)
I warmed up the sonar and 300a for my normal 2 minute tI'm period.
After 2 minutes I keyed the microphone and was surprised to see the SWR on the wm1 slowly rise above 3, (it's normally about 1.3) and watched my 2 watt dead key slowly drop down to zero.
Of course I thought big problem.
I switched the two position antenna switch over to the Madison, and keyed the microphone.
Same results.
The 2 watt dead key on the wm1 in the pep position slowly dropped to less than a watt as the SWR begin to climbed above 3.
I quickly unkeyed the microphone and checked all 5 LMR 240 jumpers for loose pl-259's. All we're screwed on tightly.
I scratched my head for a moment, and then took out the 1500 W mfj dummy load (which I've used about 2 times since purchasing it over 2 years ago.
I switch the antenna switch back to the sonar and keyed the microphone. A perfect SWR with the normal 2 watt dead key, and around 17 Watts pep.
It's snowing and as I mentioned is approximately 24 degrees with a wind chill of 8 degrees Fahrenheit.
It began snowing approximately 1 a.m. This morning (Thursday) and continues to snow with a strong wind blowing falling, and standing snow Every Witch Way.
I am happy that there's nothing wrong with my station. The dummy load proved that Beyond any doubt. But I am concerned that my IMAX 2000 may have been irrevocably damaged.
We've had colder temperatures and much more snow here in the south of jersey yet this rising SWR and dropping dead carrier has never happened before.
Is this what one might expect if their antenna was frozen over? I gave a quick look at the IMAX 2000 and it doesn't seem to be frozen over or heavily Laden with snow..
Should I just wait until Tuesday when the temperature will rise to approximately 40 degrees?
I've got a brand new back up antenna unfortunately it's an a 99. And since my IMAX is only 10 feet off the ground I'm definitely not going to downgrade. If I have to I will go ahead and purchase a new IMAX. I'm only assuming the antenna is damaged because as I mentioned above we've had worse weather conditions than this and I've never seen this type of meter readings because of bitterly cold, and snowy weather.
Has anyone experienced this only to find out it was indeed due to frost on the antenna?
Could it be the frost is at the place - so-239 connection area? If so is that something that would result in the types of readings I got with the antenna in line? Once again with the 1500 watt dummy load in line my readings for SWR were better than they are with the antenna in line. My antennas lack of height and antennas proximity to my house have always been an issue with SWR/reflected power, but nothing to really worry about. Before purchasing and installing the IMAX 2000 I was using the a 99, which gave me an SWR of 1.5. It never concerned me, but was a bit happy to see the small drop when I purchased and installed the IMAX. So. What's going on here? Is it possible the antenna has possibly cracked due to frost and or expansion? It's not as if the SWR shot right up above three immediately upon keying up the microphone. It actually slowly Rose up to slightly above 3 before I decided it was time to bust out the dummy load. Any information on this phenomenon would be greatly appreciated. 73
 

Robb said:
More like 'iced over' antenna.
Tried wobbling/shaking the antenna in order to knock off the ice yet?
Click to expand...
My imaxx is ten feet off the ground. It's mounted on a non-penetrating roof mount held down by 8 standard cinder blocks.
No guy wires. It's basically free standing and I am not sure if shaking it is a good idea. Especially if it's frozen. I'm not worried about the masts possibly breaking due to the frost but I fear there may be some delicate parts of the IMAX that might not take a good shaking. Once that fiberglass gets wobbling it seems to take on a life of its own at least in a few video clips of the IMAX in windy situations. I'm assuming from your answer you're leaning towards the idea that the antenna is frozen over, and that is a good thing. I think I'm going to wait until Tuesday when it's reportedly going to be 40 degrees. If there's any issues after the big meltdown I will add another question, but I will most likely assume that the antenna has been damaged either on the inside somewhere near the so-239 and the flimsy coil device that sits at the bottom of that antenna. I truly hope it works because I really don't want to have to replace it. Actually replacing it isn't a problem it's putting it up that's going to be a bit of a bitch. At least for me. the one good thing that might come out of it is that approximately 10 months ago I purchased a 15 ft telescopic r o h n mast. I did ask if installing it might make a difference and the response was mostly leaning towards it possibly receiving and transmitting a bit better. If I'm going to replace the IMAX with a new one I will remove the two five foot mast and install the 15 foot telescopic. I did forget to mention something in my old pay. I took out the second wm1 I own just to make sure it wasn't the meter and the second backup autek wm1 gave the exact same readings in the same exact way. Thanks Robb,
 
I have an IMAX on 20 feet of mast pipe. Back in 2008 we had a major ice storm, power was out for days and tree limbs were down everywhere. The IMAX was bent over so bad it looked like a giant candy cane. After the power came back on I shook the hell out of the mast pipe and most of the ice fell off. The antenna has worked fine since. Anytime we get ice here in Indiana I try to knock most of it off the antenna before I talk.
 
Mine was iced up for a few days here, it was 1.5.
Now its all melted and its 2.5.
Not sure what happened but I'm going to have to go up and check the coax connection.

Imax quality has been not so great these last several years.
 
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Pretty normal, I'd say. I remember as a kid when I had a Taylor Grand Slammer, and we had freezing rain in Wichita Falls. Some of the ice broke off on the vertical radiator, but the base/coil and horizontal ground planes were pretty thick with ice. I think I hit about a 2.5:1 SWR, but my Robyn only put out about 3 watts. :) Funny thing was, I remember the skip being excellent, and I didn't want to chance messing up my rig, so I just listened. Took about 3 days before it all thawed out!

73,
Brett
 
Sonar, if you didn't use coax-seal or some other type of waterproof covering for the connection from the coax to the antenna, then there is a good chance that it's this connection that is the source of your problem.

if you get the chance, disconnect it, dry it off, and try putting it back on.

if all is well, be sure to use some sealant when you are done.
LC
 
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357 said:
Mine was iced up for a few days here, it was 1.5.
Now its all melted and its 2.5.
Not sure what happened but I'm going to have to go up and check the coax connection.

Imax quality has been not so great these last several years.
Click to expand...
I couldn't say how much higher than 3:1 my swr might reach because as soon as it hit that mark i wasn't willing to see how high it would go. It could've hit the corner for all i know. I wasn't willing to find out.
The strangest thing about it was, I've never seen SWR steadily climb like that. As long as I held the d104's key down bar., the SWR was steadily moving up at a constant pace. It was just the weirdest thing I've ever seen on a meter pertaining to SWR. I'm fairly positive the cold, snow, and icy conditions was and is the cause of what happened today. I'm not going to attempt to remove any ice by shaking or doing anything else to the antenna. I'll let Mother Nature reverse what she did today.
 
loosecannon said:
Sonar, if you didn't use coax-seal or some other type of waterproof covering for the connection from the coax to the antenna, then there is a good chance that it's this connection that is the source of your problem.

if you get the chance, disconnect it, dry it off, and try putting it back on.

if all is well, be sure to use some sealant when you are done.
LC
Click to expand...
If I recall correctly, when the pl-259 was tightly fastened onto the antennas so-239 some electrical tape was used. But I can't be one hundred percent sure, and I don't even know if using electrical tape for that application is actually a good idea. I am going to wait. I'm going to let the 40 degree weather and sunshine of Tuesday or Wednesday do its job and then I will hook the lmr400 that leads from the antenna to the shack and right into the wm 1's remote in out box and take it from there. I feel very lucky as I usually do not check the SWR or radios dead key. I usually turn the radio on, turn the amp on, let everything warm up for a few minutes as I listen to the locals or some DX coming in, and then I key the microphone. I think 450 Watts may have Ben too much on the amplifiers components, even t
hough I would have noticed it right away. I don't know how long someone can key down an amplifier without an antenna hooked up, and for how long that could be done before things go bad. I remember hearing stories of people who forgot to hook up an antenna and the second they keyed up the amplifier the Magic Smoke begin to rise. I don't know if that's true as I've never had it happen to me. This is the first time I've ever had extremely two off-the-chart SWR because of what I believed to be weather conditions causing issues with the antenna. I will check the antennas so-239 and LMR 400 if the problem still exists after the Meltdown on Tuesday or Wednesday. I know no damage was done to the radio or amplifier. I caught it quickly enough. It wasn't like I was looking in another Direction and beginning a qso with somebody. I was looking directly at the SWR meter when I originally keyed the microphone. Which I never ever do except for the fact that I hadn't turned any of the equipment on in 5 weeks. That was actually the Saving Grace. At least that's what I believe. I have heard of people keying down amplifiers with no antenna for long periods without any damage and I'm not talking about ldmos amps. I don't know if the stories are true because I never seen it myself, and I actually doubt very much that a sweep tube amplifier or most any amplifier without how is WR protection would last long on a key without any antenna. Thanks for the advice LC. You know my situation and I'm hoping I don't have to do what you suggested. Being that it's very cold out there and won't be warming up for quite a while I will not be putting anyone in the position 2 get up there and have to remove that cable or even to check it. So my fingers are crossed that Mother Nature was the cause of the issue and her sunshine will correct it.
 
Sonar said:
My imaxx is ten feet off the ground. It's mounted on a non-penetrating roof mount held down by 8 standard cinder blocks.
No guy wires. It's basically free standing and I am not sure if shaking it is a good idea. Especially if it's frozen. I'm not worried about the masts possibly breaking due to the frost but I fear there may be some delicate parts of the IMAX that might not take a good shaking. Once that fiberglass gets wobbling it seems to take on a life of its own at least in a few video clips of the IMAX in windy situations. I'm assuming from your answer you're leaning towards the idea that the antenna is frozen over, and that is a good thing. I think I'm going to wait until Tuesday when it's reportedly going to be 40 degrees. If there's any issues after the big meltdown I will add another question, but I will most likely assume that the antenna has been damaged either on the inside somewhere near the so-239 and the flimsy coil device that sits at the bottom of that antenna. I truly hope it works because I really don't want to have to replace it. Actually replacing it isn't a problem it's putting it up that's going to be a bit of a bitch. At least for me. the one good thing that might come out of it is that approximately 10 months ago I purchased a 15 ft telescopic r o h n mast. I did ask if installing it might make a difference and the response was mostly leaning towards it possibly receiving and transmitting a bit better. If I'm going to replace the IMAX with a new one I will remove the two five foot mast and install the 15 foot telescopic. I did forget to mention something in my old pay. I took out the second wm1 I own just to make sure it wasn't the meter and the second backup autek wm1 gave the exact same readings in the same exact way. Thanks Robb,
Click to expand...
We are in a heat wave here 22 right now in N.W. Montana I have a Sirio 2016 I have it on a 45 mast with the base 14 off the ground (its on my deck). Anyway...lots of snow and inc here. Everyday I hook up my mfj 259c and "look" at the antenna if all is well I put a little tune up time in and Go for it. If I see a bad swr, my 0= is way off I tap with some vigor on the mast with my old wood bad, you find a nice rhythm and just a light tapping and all the snow and/or ice will drop on my head to the joy of my wife.
 
Rain, ice, and other forms of water add capacitance and it most likely will change your antennas tuning. This is where tuners come in handy.

At least you can match it up with a tuner at lower power, then key it up with 1.21 gigawatts and that should melt the ice off.
Then go back to your regular operating standards!

Some truth mixed with humor… :ROFLMAO:
 
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357 said:
It wasnt even close to as bad as last year....but the match is worse.
Pictures are last February


View attachment 22343
View attachment 22342
Click to expand...
357. That's an incredible picture of the amount of ice/snow causing that antenna to practically look like it's going to snap in half. When that photo was taken was your SWR adversely affected?
My IMAX is standing up as straight as it always is. So if it (my antenna) is indeed covered with ice/snow it must be a light coating.
Because I'm a WC user I can't get out into the yard where my antennas located because the ground is covered with about 4-8" of snow.
I don't want to have my girl dredging through the snow in order to swinger a 2 by 4 at my mast in order to loosen ice and or snow that might be covering the antenna. If I just leave it alone and wait for the Sun and rise in temperature to melt what might be possibly causing my high SWR, might it just fix itself? Should the SWR eventually drop to its normal point? This has never happened before. Even in worse weather. There's been an antenna in that same location during brutal weather and my swr's never been affected. What could be different now as opposed to the past few years when the weather, ice, snow and temperatures were 10 to 20 degrees lower then they were yesterday?
I did a Google search on ice, and cold temperatures, and the way they affect antennas used for transmitting, and I did come up with a few posts that suggested very cold temperatures, ice, and snow can cause hi SWR's. Should I just wait (don't stress) and give it another try after the weekend?
 

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