Greg,

My experience was with my 144/1268 15w DEMI Tx-converter mounted on the elevation crossboom with 7-foot of 1/2-inch hardline to a single 45-element loop-yagi. I measured 9.5w at the feed with a Bird meter.

So I think anyone considering running mode-L uplink should consider the losses to the antenna. 10w in the shack will not do it unless you use a very big dish, since you may only get 1-2w to the dish (using hardline; don't even think 9913 or such for this frequency). Above 432 it is standard practise to locate the equipment close to the antenna so you do not suffer high losses.

Directive systems makes a 6-foot loop-yagi with half the gain so one could stack two to get 20 dBi. The M2-23CM35EZ should work well, also.

We do not know what the orbit and satellite 1268 antenna/receiver parameters are, so the only approach I have is to use AO-40 experience as a guide. If P3E is more like AO-13 then you get a bit more signal which will not hurt. Let's all remember that the S1 system failed after a very short period, and S2 used a lower gain helix antenna requiring better uplink capabilities.

One should always design in a little "wiggle" room in your station. That way you can absorb some lowered performance on the satellite. This is just good engineering.

At 08:34 PM 5/7/2007, you wrote:

Hi Ed,

Yeah, I thought a loop in front of my grill might be too good to be true. While probably fine for terrestrial work, I only have 10w in the shack, so for satellite work there's no RF to waste on spillage and side lobes.

The 12' Directive Systems antennas seem to be big and very well built. Too much of both, probably. I only have a 4'-5' vertical turning radius (cross-arm to sloped roof), so mid-span on a 12' boom isn't going to work. And it weighs 5 lbs.

M2 has a 35 element beam (23CM35EZ) with similar specs, but its a little shorter and weighs half as much. I might be able to squeeze it in between the rotor and the tower cam. Anybody have any comparative experience between the two?

Thanks,

Greg KO6TH

73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ======================================