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Re: Tripped LEILA (was:Gettng on AO-40 - Uplink Antenna)



Yup that's true, but I could trip LEILA most of the time with that setup.  
At least if the squint was such that I could hear others on the bird.  If 
you can't hear your return at 50W there probably will not be all that many 
people around to work anyway...I didn't imply 100% coverage at 50W, but its 
a very practical power level most of the time.

The W0LMD patch on the dish at 435 is a great idea, but it's a bit of a 
compromise.  The gain of that combo was measured at around 12-15 dBi
(ground reflections put that much uncertainty in the measurements) at the 
CSVHFS conference where I helped W0LMD test the antenna.  This was on a 7.5' 
dish.

What this means is that the W0LMD patch feed at 435 is only about 3-5 dB 
better than the WA5VJB yagi.  At this time, they both are linear.  (W0LMD is 
working on a CP 435 patch design though.) But you, of course, gain the 
convience of having your entire up/downlink on the one antenna so it makes 
very good practical sense to do this.

Of course, the 2.4 GHz side was measured at 37.5 dBi, so there is what makes 
the whole setup worth it.  From 7.5 ft to your 12 footer should be about 5 
dB better than this.  So, at 42.5 dBi gain, you have VERY good ears over 
there.

This is compared to the "average" setup for AO-40 that has 21-25 dBi gain 
for the downlink.

This is why I plan on using either the 10' or the 7.5' dish I have when I 
finally get moved into my new rural QTH.

73, Fred W0FMS

>From: "Reinhard Sual" <tdsrhs@cbn.net.id>
>To: <amsat-bb@amsat.org>
>Subject: Re: [amsat-bb] Tripped LEILA (was:Gettng on AO-40 - Uplink 
>Antenna)
>Date: Wed, 14 Aug 2002 10:36:39 +0700
>
>Frederick M. Spinner Said:
> > Well, I've tripped LEILA with 50W out and a WA5VJB Cheap Yagi (11 ele
>linear
> > polarized), so I think you'll be fine.  True I had a VERY short cable 
>run
> > (like 10 ft at the time)...
>
>Tripping LEILA is a variable occasion, depending on both Satellite Height
>(Distance) and Squint angle.
>Last nite, while having a QSO with Roy - VE7BPB, I have to reduce my power
>to the minimal (2 watt) not to upset LEILA.
>But on another occasion, even at the fullest 50 watt, I can barely heard my
>echo (especially when the Sat on Apogee with bad Squint > 35).
>I am using a W0LMD 435Mhz Patch on my 12 feet dish, with about 60 feet 
>9913.
>
>Reinhard - YB0KTQ
>Grid: OI33lt
>
>
>
>----
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