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Author Topic: That topic again...groan  (Read 3271 times)

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That topic again...groan
« on: October 11, 2008, 07:30:11 PM »
I raise this question only after having read all the forum posts on the topic and several articles from external sites. Yet I am still not clear on what is effective/needed and what is not, sorry. (I can hear the groans from here)

I have a RadarRama antenna mounted on a metal mast connected to my brick chimney about 30' up on my roof. Directly below the antenna is connected the Elad A12-1090  pre-amp, connected to 60 feet of Times Microwave LMR-400, which then connects inside to the AS-1090BT Bias-T. From there a 3 foot LMR-240 cable to the Radar Box.
The LMR-400 coax is not grounded at the entry point to the house via the coax outer screen (yet). The Bias-T is powered by a regulated 12v 800 mA AC adaptor. All computers and PSU's for radios run into line a power conditioner and Tripp-Lite IsoTel surge protectors.

All working brilliantly.

However I live in the mountains and we routinely have very low humidity and high winds - 40 to 50 mph wind gusts are common at night, all night and even higher during some days. Rarely have any rain or thunderstorms.

So far all ok but:

1. Is my Elad Pre-amp protected 'enough' for these wind levels?

2. If other protection is required for the Elad pre-amp or the RB2009, exactly what is it?
I see some posts saying use DC blockers and others indicating they are ineffective.

3. Should I be concerned enough to replace the RadarRama (not at all the best purchase I ever made anyway) with something DC grounded like the SSE 1090SJ mk2, immediately?

4. Does the DC-grounded N-connector on the SSE 1090SJ mk2 affect/prevent me from using the Elad pre-amp? I think there is no actual power into the antenna so should not matter but just asking.

Sorry if this is too detailed or rehashing all this again; I only want to be clear about what I factually need to worry about or not. I am clear on the fact that lightning does what it wants and nothing will guarantee protection there, I just want to avoid stray electrical from winds causing damage.

« Last Edit: October 11, 2008, 07:35:06 PM by oceans777 »

AirNav Support

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Re: That topic again...groan
« Reply #1 on: October 11, 2008, 07:45:48 PM »
The key here is the Bias-T. Its designed to take out the DC current and hence there is no dangerous amount of current going back to the RadarBox.

If you are concerened you might want to get a grounded antenna or something which is designned to handle static better than the RadarRama.

Personally there is very little to worry about. The customers who have had issues in the past can be counted on one hand out of 1500+ RadarBox customers. Out of those none had a the elad preamp and bias T.
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Re: That topic again...groan
« Reply #2 on: October 11, 2008, 07:49:32 PM »
Thanks Support! Thats all I needed to know - I wasn't in any way suggesting the RB was the problem, I know I have to protect our Icoms, AOR's etc as one would with any receiver.

Absolutely loving the RB2009 - thanka for all your hard work and excellent support!


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Re: That topic again...groan
« Reply #3 on: October 11, 2008, 08:38:44 PM »
Hi Oceans 777, I would suggest you bear in mind that nice dry wind and the low humidity you're lucky enough to have are likely to put a static charge into any object thrust up into them!    As a Coastguard (voluntary) we have to work with helicopters and when using a high line (a line lowered by the helio crew) the bottom end is a wire rope, which has to be allowed to touch ground or sea surface before anyone tries to grab it - the rotary blades cause the helio to become highly charged with static.
ANRB :  AOR AR8000 : Icom R-7000 : Icom IC-R9000 : JRC NRD-545 : OptoElectronics Digital Scout and OptoLinx Interface; Realistic Pro-2005 : UBC 800XLT - listed in alphabetical order, not cost, preference, performance or entertainment value!


  • Guest
Re: That topic again...groan
« Reply #4 on: October 11, 2008, 08:45:13 PM »
Very true! I am going to replace the antenna anyway and ground the coax.
Looks like there is good protection in between short of catastrophe so we
should be good to go. Thanks!