[amsat-bb] Re: New Lindy's QRV

Mark Spencer mspencer12345 at yahoo.ca
Tue Feb 9 08:41:57 PST 2010

I can consistently copy the beacons on FO 29 and HO 68 down to the horizion using a larsen 2/70 mobile antenna with the larsen radial kit.   The feed line is approx 60 feet of Belden 9913F.    I typically connect the antenna to a comet duplexer to my mirage UHF amplifer which has a gasfet preamp and use my  FT736 as a receiver, but the 736 can copy the beacons with the preamp switched off.  I have an ARR gasfet preamp that works a bit better but is not TR switched and I usually don't bother with it.   VO52 is also typically copyable down to the horizon with this setup.  

I haven't been on the FM sats in a while but don't recall any issues copying them either.   

I have been told by several people that my ears seem to do a better job than others at copying weak signals though (:

----- Original Message ----
From: Bill Dzurilla <billdz.geo at yahoo.com>
To: amsat-bb at amsat.org
Sent: Tue, February 9, 2010 6:23:18 AM
Subject: [amsat-bb] Re: New Lindy's QRV


I would be suspicious of the construction.  I can get a few minutes of good copy from AO-51 on a high pass with just a rubber duck on an HT.  If you do get a preamp, the run between the antenna and the preamp is critical, so if possible keep it short and use good coax.  Ed seems to be having success with 4' of RG-58U, but generally the use of any RG-58U at 70cm is not a good idea.

Here's a quick summary of my results with various antennas:

* HT and rubber duck or other antenna mounted directly on the HT - success only at high elevations
* HT and Arrow or Elk antenna, no preamp - success from horizon to horizon, if no trees or other obstructions
* base rig and dual band omnidirectional ground plane, no preamp, 40' of RG-213U - success on most birds only when elevation is above 25-35 degrees
* base rig and dual band omnidirectional ground plane, ARR preamp, 40' of RG-213U - success on most birds when elevation is above 15 degrees
* base rig and Elk antenna on 12' pole at 15 degrees fixed elevation, azimuth rotation with old TV antenna rotor, ARR preamp, 70' coax run (my current setup) - full success from horizon to horizon on all birds, except in directions where blocked by trees or roof.

The Elk is $135 shipped and the used rotor was $25, and this combo is by far the most effective I have used.  My community has antenna restrictions, but so far no one has complained about the little 2' long Elk.  The Elk could be replaced with a homebrew Cheap Yagi or tape measure yagi, which can be built for $10.

I am not aware of anyone who is able to work the sats at low elevations with any type of omnidirectional antenna, even with the best preamp.  You can have plenty of fun working the birds at higher elevations, but you will be able to work more passes and better DX (e.g., Europe on AO-7) if you can catch them at lower elevations.

73, Bill NZ5N 

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