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
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb