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marieL
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ICE on antennas

Mon Dec 29, 2008 1:20 pm

Hi all.
I use panel antenna but in this season an ice layer cut me some point to point.
Singnal level and signal to noise remain constant but the ccq go to 0.

Have someone experienced anti ice solutions for panel antennas ?
Spray, paint, thermal solutions ?

Could someone give me some hints ?

Thanks to all.

marie
 
bmeiojas
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Re: ICE on antennas

Sat Jan 10, 2009 8:40 pm

Hi!
can u tell me what kind/model of panel do you use?. I've got some Hyperlink 17dBi panels working "good" under really servere conditions (even with snow) and i never have a downlink
 
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tgrand
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Re: ICE on antennas

Sat Jan 10, 2009 9:38 pm

I would be inclined to think that it is a radio failure and not the ice.
The reasons for this are simple, ie:
R52H has an operating temp. at around -20c.
R5H has an operating temp at around 0c.
R52 has an operating temp at around 0c.
XR5 has an operating temp at -40c.

If the reported wind chill is at -40c, then on a tower exposed to full wind with metal enclosure, the devices could experience temp well below -50c.

How long would you think that radio would last??
especially if it were rated at only 0c.

I do not know how cold it gets where you are located, but here we see these temps frequently ( at least this winter for sure).
 
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roc-noc.com
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Re: ICE on antennas

Sun Jan 11, 2009 4:31 pm

I would be inclined to think that it is a radio failure and not the ice.
The reasons for this are simple, ie:
R52H has an operating temp. at around -20c.
R5H has an operating temp at around 0c.
R52 has an operating temp at around 0c.
XR5 has an operating temp at -40c.

If the reported wind chill is at -40c, then on a tower exposed to full wind with metal enclosure, the devices could experience temp well below -50c.

How long would you think that radio would last??
especially if it were rated at only 0c.

I do not know how cold it gets where you are located, but here we see these temps frequently ( at least this winter for sure).
My R5H data sheet says -40 to +80 C.

http://www.roc-noc.com/pdf/R5H/R5H.pdf

I don't believe the other data sheets. I have a few hundred R52 in the air and they are reliable at all temperatures that we reach. I have not had one R52 failure except for a direct lightning strike. Our winters reach about -10 F (-23 C) and summers reach +105 F ( +40 C).

The only Mikrotik product I used that was bad in the cold was the RB112. I had a couple of these that would not start up on a -10 F day. I brought them inside to warm up and then they started and stayed running outside.

It could be that the heat generated in normal operation allows all of these radios to stay above their minimum rated temperature.

Tom
 
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roc-noc.com
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Re: ICE on antennas

Sun Jan 11, 2009 4:38 pm

Hi all.
I use panel antenna but in this season an ice layer cut me some point to point.
Singnal level and signal to noise remain constant but the ccq go to 0.

Have someone experienced anti ice solutions for panel antennas ?
Spray, paint, thermal solutions ?

Could someone give me some hints ?

Thanks to all.

marie
What was the snr (signal to noise ratio) in normal weather with no ice?

I use dish antennas with radomes for most of my PtP feeds to keep the ice and snow accumulation down and to keep a healthy snr. I consider a healthy snr to be 35 to 40. That gives me enough SOM (safe operating margin) to lose 10 or 20dB and still stay connected.

Tom
 
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tgrand
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Re: ICE on antennas

Mon Jan 12, 2009 1:46 am

I stand corrected on the R5H, it is in fact -40c.
That said; Unless you have something other than air and metal enclosing those radios they can and do fail.
The heat-sinks are large and radiate heat extremely quickly at fridgid temps.

A 12v incandesent automotive bulb within an inch of the heat sink should be sufficient during fridged bouts of tempurature.
 
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jp
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Re: ICE on antennas

Mon Jan 12, 2009 3:34 am

I haven't used those radios but I certainly wouldn't if they stopped working below -30c!

Most of my gear utilizing radio cards is indoor, but that can be pretty cold too as those tower sites are unheated. I've got CM9 and SR5 cards in -30c occasionally without problem.

BTW, if windchill is -40, the gear can not be -50 unless they are physically evaporating in the process. In fact, they shouldnt go below the real temperature, regardless of the windchill in below freezing weather. It could in warm weather due to evaporative cooling in proximity, but not in below freezing conditions. The antenna will simply be a better heatsink and help it reach the real temperature more quickly.

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