[amsat-bb] Attaching the coax to antenna boom

[Frank Karnauskas]

This is quite curious.

Page 1 of the WA5VJB paper says, "Run the coax back down the antenna
and along the boom keeping the radius small..."  His hand-drawn
illustration shows the feedline going down the boom then making a hard
turn at the boom-to-cross arm plate.

The M2 instruction sheets for the 2MCP8A and 436CP16 antennas both
state (in bold type), "Do not route feedline to boom to mast plate  as
exiting antenna here will adversely affect circular field."

Mr. Britain's paper is obviously focused on mounting the cross bar
somewhere along the boom of a somewhat long antenna.  The M2
instructions are for mounting short antennas from the back of the boom
to the cross bar. Not the same situation.  But, for a newbie like me,
the definitive conclusion to this discussion is...I am still confused.

I was hoping to hang my M2 LEO antennas Monday morning but now not
until after I call the M2 support line for their read on this.

73,
Frank

FRANK W. KARNAUSKAS, N1UW
ARRL MINNESOTA AFFILIATED CLUB COORDINATOR
AMSAT NEWS SERVICE ROTATING EDITOR
1402 SUMMIT SHORES DR.
BURNSVILLE, MN 55306
N1UW at GOKARNS.com
612-644-9174


-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Gary
Sent: Sunday, March 17, 2019 2:29 PM
To: radiomb; amsat-bb at amsat.org
Subject: Re: [amsat-bb] Attaching the coax to antenna boom

Yes, you can, just pay attention to how far your coax turn is from
your driven element. There are a couple spots to avoid.

It is pretty well explained in Kent Britain's (wa5vjb) paper here:
http://www.kk0sd.net/metalboom/metalboom.htm

73,
Gary kk0sd


-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of radiomb
Sent: Sunday, March 17, 2019 4:04 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Attaching the coax to antenna boom

   Building my new ground station and another question. I have always
only elevated my antenna 90 degrees. I loose about 20 25 seconds while
the azimuth rotator turns 180 degrees to track the rest of the pass. I
have just let the coax hang off the back of the antennas in a big
loop. I am afraid it will get hung up going 180 degrees. Question, Can
I attach the coax to the antenna boom and run it back until it gets to
the cross boom or will that throw off the radiation pattern?   
Thanks 73
  Mike K4MIA

 
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