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Author Topic: Pre-amp set back or mast head ?  (Read 2157 times)

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Dana

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Pre-amp set back or mast head ?
« on: March 27, 2012, 11:33:08 AM »
I just installed a Jim M75 pre amp in the back side of my RB. The number of contacts increased  only with 5% and the range no more than 5 to 8 NM in some directions…
I am using 8m of Ecoflex 10 , and GP 1090 antenna located on the roof. I am curious to know if someone used this Jim M75 amp mast head, close to the external antenna and if  you can get better performance instead of using it set back near the radar box ?
Thank you

nortonbeak

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Re: Pre-amp set back or mast head ?
« Reply #1 on: March 27, 2012, 04:57:57 PM »
Jim M-75 is a broadband pre-amp. You would be optimistic to expect a much better increase in performance from that which you have noted.

It would be difficult to weatherproof the pre-amp if you mounted it outside and I suspect getting the power to it may again be a problem. Obviously, if you relied on battery power while it was outside, I imagine that they would not last more than a few days with the unit permanently on.

CoastGuardJon

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Re: Pre-amp set back or mast head ?
« Reply #2 on: March 27, 2012, 05:10:17 PM »
Hi Dana, as NB says, the Jim M75 is a broadband pre-amp designed and built to be used indoors with wide-band scanners, not SBS or RB.    For RB use you need to get a 1090 pre-amp and site it as close to the antenna as is practically possible.    HTH
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