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Re: Multiplexing radios



Hi Joel.

The losses are mainly in my coax - which is 150'. Yuk. I'm a basement apartment
dweller in a 'conservation area', and I have to be _real_ careful putting in
anything outside. The roof is at about 110'.

I estimate that I get about 4-5dB on 144MHz and 9-10dB on 70cm with the coax
I have. Double yuk.

I guess that I get about 3dB of losses through the filters, linears, preamps
and triplexers.

You're right about all the losses, but so far it's by far the best configuration
I've tried.

Note the linears and preamps for 2m/70cm. These (especially the preamps) help
enourmously.

I've had a harness built with a pair of low loss Westflex-103 feeders (like
9913), a pair of rotator cables and 30 control lines, but I haven't had the
courage to attempt putting it up yet!

Regards, Howard G6LVB

>I went to your page - very interesting; however, I have one question, How
>much loss is in your system with all the triplexers, duplexers, connectors,

>etc?  I have to listen thru trees and *any* loss in signal strength is
>unacceptable.  I have two runs of 9913F about 50' with four N-type
>connectors on 70cm (with an estimated loss of 0.5dB) and two PL-259/SO-239

>connectors (an estimated loss of 1dB) with two N-type connectors where I
>could on my 2m side.  If I stay at my current QTH for any length of time, I

>have 350' of 7/8" hardline that I plan on running up my tower.  Of course,
I
>will have elevated the tower above the trees which are 100 - 125' tall.
>
>73,
>Joel, K2SAT
>
>----- Original Message -----
>From: Howard Long <howard@howardlong.com>
>To: <amsat-bb@AMSAT.Org>
>Cc: James Cutler <jwc@Stanford.EDU>
>Sent: Friday, May 26, 2000 4:32 AM
>Subject: Re: [amsat-bb] Multiplexing radios
>
>
>> Hi James.
>>
>> I don't know if this is any use, but I run something a bit similar in
>order
>> to remotely switch 2 preamps and 4 antennas, all from a single RG-213
>> feedline with 400W of power.
>>
>> I use a PIC 16C876 and other components to control my antennas. This
>> interfaces with a PC via a serial line.
>>
>> Total cost for the controller so far is about $50.
>>
>> Check www.btinternet.com/~hlong/G6LVB.htm for more details.
>>
>> Cheers, Howard G6LVB
>>
>> ----- Original Message -----
>> From: James Cutler <jwc@Stanford.EDU>
>> To: <amsat-bb@AMSAT.Org>
>> Sent: Friday, May 26, 2000 1:25 AM
>> Subject: [amsat-bb] Multiplexing radios
>>
>>
>>  >
>>  > Does anyone know of a computer controllable multiplexor that will allow

>>  > mutliple radios to be attached to a single antenna feed line?
>>  >
>>  > Thanks.
>>  >
>>  > --Jamie Cutler, KF6RFX
>>  > jwc@stanford.edu
>>  >
>>  > ----
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>>  >
>>
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>
>
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