[Amps] W3NQN band pass filters

[Karl-Arne Markström]

First, I would suggest that you check that the indicated return loss is > 30 
dB when the MFJ-269 is terminated with a known good 50 ohm termination.

It is difficult to optimise return loss performance when aligning a filter 
only in the transmission domain,
so if return loss is of concern, I would suggest the use of a network 
analyser (scalar or vector) that can display both transmission and 
reflection, preferably at the same time.

>From a practical standpoint, 20 dB return loss does not affect system 
performance significantly.

73/

Karl-Arne
SM0AOM

----- Original Message ----- 
From: "Alton McConnell Avon-Cadillac" <amcconnell at avonauto.com>
To: <amps at contesting.com>
Sent: Monday, June 09, 2008 2:03 PM
Subject: [Amps] W3NQN band pass filters


>I am trying to align some W3NQN band pass filters that I have built for
> club use. I am using the design from the May and June 1998 QST article.
>
> I am using a HP 8656 Signal generator and a 30 MHz scope for the tuning.
> Measuring the return loss with a MFJ 269 SWR analyzer, the best that I
> can do is 20db.
>
> Any suggestions for alignment of the filters?
>
> Alton, NU8L
> Amcconnell3 at hotmail.com
>
>
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