[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: RE: DSS Dish

This afternoon I finally got my homebrew 26" dish mounted on
my rotors.  At the moment it is doing really really well.
It is copying the beacon perfectly, at about 4 S-units
above the noise.  This is with a 27 degree squint at 43000 km range.

It is much better than the 13-turn helix I was using until now.
Under the current conditions, I would have expect the helix
to get maybe 50% CRC good telemetry blocks.

The dish is made from 12 one-foot-long 1/4" square metal rods welded to a
central hub like spokes of a wheel.  They are each bent in two places
to form an approximation of a parabola, and the whole thing is covered
with a round piece of metal mesh. It uses a 4-turn helix for a feed,
connected to my DJ9BV preamp and a old DEM convertor.

I'll see how well it does later tonight when the transponder turns on.
At the moment there is 10 feet of cheap RG-58 coax between the preamp
and the convertor.  As soon as it stops raining I can replace that
with some LMR400, and I'll probably get another dB or so.


At 05:50 PM 5/22/01 , you wrote:
>The note you reference is from last Friday.  I have since recounted my
>experience Friday night with the DSS dish, but in brief...didn't hear
>"nuthin" with it.  Mike had a small BBQ dish [about 9 x 30 inch, I guess]
>which Mike thinks is about 21 dBi gain [derates to 18 dBi for
>cross-polarization to a dipole feed].  With it I could just barely make out
>the beacon at a squint of ~7 deg, range 61,000 km.

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org