Effect of Ice on SWR

[barnettbill]

Being the curious type that I am I decided to see what effect ice buildup on an antenna would have on SWR. I had recently set up a Firestik Firefly with a stake mount on my truck. I run a Uniden 980. I recently set this up and had an SWR of 1.18 :1 on Ch 1 and a 1.2:1 on Ch 40. Today I noticed a 1/8-1/4 inch coating of ice on my antenna and decided to check the SWR... HOLY S#!T BATMAN!!! 2.9:1 on Ch 1 and 3.0:1 on Ch 40!!! I cleared the ice off and the numbers returned to normal. Does this mean we need to use caution in icing conditions and clear the antenna? I would say yes. How 'bout the rest of you.

 

[w9cll]

Ice will detune the antenna as you have found out. Knock the ice off and the SWR will retune to normal. One of the nice things about running a screwdriver antenna is it does not matter about the ice as I can just retune it.

 

[GnG8d]

I'd check your meter, that tune seems awful flat across 40 channels for a Firestik.

 

[AL567]

I'd check your meter, that tune seems awful flat across 40 channels for a Firestik.

Wonder if he checked it with the internal meter of the 980. The 980 I have shows a lot lower swr than what it really is.

 

[W5LZ]

Can it make a difference? I think you can answer that one, right? How much difference depends on the antenna, some are more susceptible to icing than others. And then, it can depend on how much ice there is too. Or water, or bugs, or who knows what else.
And to make it a bit more interesting, it depends on how 'clean' that water, ice, or snow is too. How much 'minerals' are dissolved in it.
- 'Doc

 

[Captain Kilowatt]

I think you answered your own question. Ice detunes the antenna and therefore that what was a good SWR when dry may certainly not be anything near that when encased in ice. Some antennas seem to be more affected than others mainly due to their design. Commercial VHF and UHF have plastic or fiberglass covers called radomes to prevent ice from building up on the antenna and detuning it which could lead to a transmitter failure or loss of communications link.

 

[Roger That]

Firestik suggests at least once a month it is a good idea to wipe down the antenna with a rag dampened with Armor-All, WD-40, CRC-56, Silicon spray, etc.., to prevent ice and debris build-up [number four]

FIRESTIK ANTENNA MAINTENANCE

Their website is LOADED with useful information and is worth checking out no matter how much you know about radio communication



It's also a good idea to frequently clean road salt from your stainless steel antenna to keep SWR's down. Conductivity increases as salinity increases. Thicker salt/sodium build-up results in higher SWRs

 

[The DB]

Careful with that site. There is a good chunk of information there that is not accurate, but it sounds legit. There are also several known myths perpetuated on that site.


The DB

 

[Captain Kilowatt]

Careful with that site. There is a good chunk of information there that is not accurate, but it sounds legit. There are also several known myths perpetuated on that site.


The DB

Yup.

 

[w9cll]

Careful with that site. There is a good chunk of information there that is not accurate, but it sounds legit. There are also several known myths perpetuated on that site.


The DB

Biggest myth is their antennas work

 

[hookedon6]

Firestik suggests ...
Their website is LOADED with useful information and is worth checking out no matter how much you know about radio communication...

I about died laughing when I read this:

"We have also found that peanut butter works really well at cleaning the antenna while adding a protective oil coating that adds sheen to the covering."


THATS the reason they don't "hear" very well,............

they have peanutbutter in their ears:headbang:headbang

 

[Groundhog KSS-2012]

Careful with that site. There is a good chunk of information there that is not accurate, but it sounds legit. There are also several known myths perpetuated on that site.


The DB

Agree. ESPECIALLY the myth, "You need 18 ft of coax".
That's BS. I don't care who ya are.

 

[Rick330man]

We've haven't experienced ice on an antenna down here since the ice age. Then again, the age of this thread goes almost that far back.

 

[jdchet]

You should see what ice on a 6 foot Skipshooter tilted 45 degrees does to it! At 67mph, I never saw an antenna move side to side like that! If nothing else these antennas are strong!

JD

 

[jdchet]

You should see what ice on a 6 foot Skipshooter tilted 45 degrees does to it! At 67mph, I never saw an antenna move side to side like that! If nothing else these antennas are strong!

JD

BTW the SWR was off the chart! Tried keying up and the radio said "Aw hell no"!

JD