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Re: Seeking Mode JA System Opinions



Well, Eric I run these satellites mobile in my truck.
Here's my lineup:
2m uplink:  IC-290H and a 100W brick to a M2 HO-loop antenna.  Probably
around 80W ERP or so.
70cm downlink:  M2 eggbeater with about 10' of 9913 to an ARR preamp
(.65dB NF, 17dB gain) with my FT-100 as RX.
Ask anyone...I work the birds w/ no problem.
The only wish-list item is switchable CP on the downlink...Jerry K5OE
has some info on his website on switchable CP eggbeaters and
eggbeater-like antennas.

Eric June wrote:
> 
> Hello all,
> 
> I am an old HF guy who is just starting out with the satellites.  I have
> made a dozen or so contacts on RS-12 using equipment lying around the
> shack, and now I would like to take the next step and become QRV on the
> Mode JA LEO birds (FO-20/29, AO-27, UO-14).  My main constraint is some
> vague CC&R language that doesn't specifically prohibit ham antennas, but I
> would like to keep as low of a profile as possible.  I am therefore not
> shooting for an AO-40 or AO-10 capable station at this time.
> 
> I currently use my IC-706MKIIG (50W) feeding an M2 Egg Beater via 70-ish
> feet of 9913FX on the 2m uplink.  If I assume that the gain of the antenna
> roughly cancels the coax loss, I get around 50W ERP on 2m.  I may increase
> this 3dB to 100W in the future if I pick up a TS-2000, poor intermod specs
> (?) not withstanding.  I believe that the continued use of this
> omni-directional antenna setup should be fine for the Mode JA uplink on the
> LEO birds, am I correct?
> 
> For the 70cm downlink, I haven't been able to locate my "ideal" antenna,
> which would be a crossed yagi with about 6-7 element pairs.  So, I ordered
> a SP-7000 preamp from SSB Electronics (.9 dB NF, 10-20 dB gain) and will
> mount that on the mast with whatever antenna I end up going with.  This
> antenna/preamp would also be fed with 70-ish feet of 9913FX.
> 
> For the antenna, I am currently leaning toward a Cushcraft A449-6S, a 6 ele
> end-mounted LP yagi.  This would sit on a mast protruding from my rear deck
> with a Channel Master 9521 TV rotor for Az rotation.  I would incline the
> yagi upward at about 30 deg and do without elevation control.  The yagi is
> designed for the FM portion of the band, I'm not sure what VSWR will be in
> the satellite band, but I don't really care since it is a receive-only
> antenna.
> 
> I considered an Arrow II (leaving out the 2m elements) but it is really
> intended for portable operation, and I am in a mountain location where
> 70-80 mph driving snow is not unusual.  The M2 436CP30 is way too big for
> my location and would probably be overkill anyway.  An 11 element yagi
> might be nice, but I don't think I can end-mount it.  If the 6 ele
> Cushcraft performs poorly, I suppose I could buy a second and phase them to
> get more gain and CP instead of LP.
> 
> I'd appreciate any comments, insights, opinions, or recommendations from
> you satellite veterans.  Do I have enough "oomph" on the downlink?  Any
> better ideas?
> 
> 73,
> 
> Eric, KU6J
> 
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