[amsat-bb] Re: adding UX-910 to radio

Edward Cole kl7uw at acsalaska.net
Sun Nov 22 11:15:05 PST 2009


Another consideration for installing 1296 into a radio that will be 
desk located is the feedline loss at 1296.  If your antenna is a long 
coax run from the radio, you may lose too much RF power and suffer 
too much deterioration of noise figure using an inside unit.  The 
advantage of separate 1296 units is that one can run the IF over the 
coax to the tower-mounted 1296 converter/amplifier and only a short 
run to the antenna for 1296.

I have one of the very rare DEMI 144/1268 Tx converters (15w out) and 
will be mounting it on the crossboom of my satellite array.  This 
means I can run cheap RG-213 on 144 from my radio and about 10-foot 
of 1/2-inch hardline from the DEMI to the antenna (losing only 1-2w 
of output).  For AO-51 this is way more than needed power, but for a 
MEO or HEO one needs much more power than 1-2w.  I should have about 
1300w ERP.   My satellite tower is 150-feet from the shack.  You 
would need 1-5/8 inch hardline to get any useful RF on 1296 over that 
long a run.

In fact I have just installed a 120-foot run of 1-5/8 inch hardline 
for my eme tower and I have a 1296 loop-yagi (for terrestrial use) 
that I feed with 60w.  I will be lucky to get 30w to the 1296 antenna 
with this hardline (coupled to 45-foot of 7/8 hardline running up the 
50-foot tower).  I have a GasFet preamp at the antenna so that coax 
losses don't affect receiver NF.

The trick that many mw hams use is to locate the mw equipment close 
to the antenna and avoid coax line losses.

73, Ed

At 08:07 AM 11/22/2009, Stan, W1LE wrote:
>In addition:
>
>A transverter is always possible to get on the 1.2 GHz band.
>Use a IC-706 MK2/G or similar radio as a 28 MHz IF.
>
>Transverters are available from DEMI and DB6NT and others, or homebrew
>ala W1GHZ.ORG
>
>Use the building block approach instead of the one box doing all.
>
>Of course, integrating your system with different building blocks is
>more complex than a "one box does all" approach.
>
>Stan, W1LE
>
>
>Jack Barbera wrote:
> > I've been thinking about adding the 1200 MHz band unit to my 910 
> radio.  My dilemma is foremost that will this band be used on any 
> of the  new satellites?  The rumor is that the 910 radio may be 
> discontinued.  The question I have is whether to quickly obtain the 
> module in the event that this is also discontinued.  I would really 
> appreciate any thoughts on what action I should take.  I do like 
> ICOM products but find it difficult to get information about this 
> type of situation.  Thanks for any input. Jack WA1ZDV
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