[Wswss] M2 23cm yagi match

[kr7o at vhfdx.com]

Mike,

You didn't mention which 23cm antenna, but Mike (K6MYC) typically uses a 
"gimmic" to match the 902+ yagis by bending the DE (forward I think) to 
achieve the desired VSWR.  He is so good at this that he visually looked at 
my antennas, said "let me fix the match on those", adjusted the bends, put 
them on his sweeper and they were dead on.  Not sure if that is in the 
manuals.  An FYI since you didn't mention the model, if you are running the 
model with CNC cut element assemblies and it has the fiberglass boom you 
will want to get the aluminium boom conversion as the fiberglass booms 
ended up putting the gain curve peaked near the satellite band (doesn't 
affect ability to match at 1296 though).

Also, I have seen different feedline lengths cause divergent VSWR 
measurements at 1.2G.  I have also seen dirty or mis-seated Bird 
elements/contacts cause false readings.

K6MYC is currently in Papua New Guinea on an expedition, but he can 
probably fill you in better after he returns (if you still have issues).



At 06:11 PM 10/22/2008 +0000, eaglepoint.or at juno.com wrote:
>I have four of the M2 35cm yagis and a near by
>ham friend has two more of these antennas.
>
>We have had some pretty strange success/lack there of
>in getting these antennas to match.
>Seems the BEST we get is about 13 dB return loss(1.58:1 vswr).
>I am using a pair of bird meters, an Icom 1271 transceiver
>as a signal source, a circulator on the output of the transceiver
>to isolate the radio from changing load impedances (and there fore
>wandering output power levels).
>
>Last night I tried a driven element as described in an antenna
>article by Jim Kiltzing from his 23cm yagis. The vswr was
>still pretty poor. I then took out the first director
>and the reflected power dropped to ZERO !
>Have to set up my portable signal source and see what the
>gain of the antenna looks like (relative of course)with and
>without this first director as this may make a giant detriment
>to the launching of the signal down the yagi structure.
>
>Just looking for comments as to experience with these antennas.
>
>Mike
>WB6FFC
>
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73, Robert KR7O/YB2ARO, DM07ba/OI52ee  (ex.  N7STU)
kr7o at vhfdx.com

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