Dave-
Shortening the antenna raises the resonant frequency, lengtlhening it decre
ases it.=C2- No, if it is a hassle, it would not be worth changing the ca
ble.=C2- If you do the graph, you will get a better picture of just where
you are.
Jim
----- Original Message -----
From: "david park" <dpark748@hotmail.co.uk>
Sent: Friday, March 26, 2010 6:12:46 PM GMT -05:00 US/Canada Eastern
Subject: RE: Europa-List: Antenna tuning
Jim,
Thanks for that, yes I did use the coax that came with the kit - major job
to change that now - unless it is worth making a connection in the tail are
a to the kit coax with RG58??
I am just a bit concerned that if I keep cutting to achieve 1,5 at 127.5, p
resently 133.0 I might bxxxxx it up compleyely!
Dave=C2-
Date: Fri, 26 Mar 2010 21:59:15 +0000
From: jimpuglise@comcast.net
Subject: Re: Europa-List: Antenna tuning
David-
=C2-
I assume you are talking about the copper strip antenna that comes with the
kit.=C2- My own approach is to start at the bottom of the band and recor
d the SWR every 50 khz.=C2- After you have done this, put the figures in
Excel and graph it.=C2- Each line in your Excel spreadsheet shoud have on
e frequency in column A and the SWR at that frequency in column B.=C2- In
this way, you can see what the antenna is doing through the entire band.
=C2- You need to be concerned that the SWR is not extremely high at one e
nd and extremely low at the other.=C2- I usually shoot for 1.0-1.2 / 1 at
the center and 1.9 or so at each band edge.=C2- If you are at 1.5 in the
middle of the band, that should be just fine.=C2- The reason you are not
seeing change with small adjustments is that it is probably relatively fla
t a few MHZ each side of resonance.=C2- Also, I don't know if you are usi
ng the coax that comes with the kit, but I took one look at it and threw it
away.=C2- Invest in some good RG-58 for the comm antenna and some RG-400
for the transponder.=C2- When you look at the graph, it will be very obv
ious what you need to do.
=C2-
Jim Puglise A-283
----- Original Message -----
From: "david park" <dpark748@hotmail.co.uk>
Sent: Friday, March 26, 2010 5:43:11 PM GMT -05:00 US/Canada Eastern
Subject: Europa-List: Antenna tuning
I have just borrowed an SWR meter and am trying to tune my Comm antenna.=C2
- The manual says to tune by shortening=C2-until minimum reading at 127
.50=C2- I am getting Minimum reading at 133.00. My last two cuts of 3mm h
ave not moved the minimum reading 1.5 at 133.00 above and below this freque
ncy the readings are at 1.9 -1.9.
Do I keep shortening the antenna????
Any ideas?=C2- Regards Dave Park=C2- G-LDVO
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