Re: [amsat-bb] Hardline and connectors (long)

[John Charles <m1btr@xxxxxxxxxxxxxxxxxxxx>]

In message <000901becd72$a18a16e0$0c59ccd1@win95>, John Zaruba Jr
<jzaruba@snip.net> writes

> As a
>practical matter, how much effect does impedance lumping present in real
>world operation? On receive, both feed lines will have preamps mounted at
>the antenna. My maximum transmit power is 40 watts on 145 Mhz and 35 watts
>on 435 Mhz.

Hi John,

My only practical experience:
I had a 2m FM rig feeding a dual band colinear and the rig had an SO239
so I put a PL259 on the feeder.

I changed the rig for a 2m / 70cm dual bander which has an N skt. At
first I just put in an adaptor but after a while noticed I couldn't get
full power on 70cm. The VSWR looked OK but of course that was being
measured after the adaptor and 259.

Changed the 259 to an N type plug and got rid of the adaptor. Result -
full 35W instead of the maximum 22W I had before.

Now there may have been other variables - how well had I bonded the 259
for example? but it convinced me to only use N types wherever possible,
especially at UHF.

73  John  M1BTR  Lincolnshire, England
-- 
  m1btr@midmarsh.demon.co.uk         M1BTR@GB7SKG
  QRV 6m 2m 70cm       Member: BATC RIG RSGB UKRS
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