Topband
[Top] [All Lists]

Re: Topband: MFJ 259B on 160M

To: Glen <k4kv@mds-ham.com>
Subject: Re: Topband: MFJ 259B on 160M
From: mstangelo@comcast.net
Date: Mon, 28 Sep 2009 13:39:58 +0000 (UTC)
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Glen,

The problem with using a filter ahead of your "wideband" MFJ-259 analyzer is 
that the filter will transform the impedance of the load you're trying to 
measure.

You have a better chance of measuring the impedance in the presence of a strong 
signal. with a "narrorband" vector network analyer such as the N2PKVNA (kit) or 
AIM4170.

If you do need a filter both units enable you do perform a "OSL" calibration 
with open, shorted and 50 ohm load calibration with a filter inserted in front 
of the input.

In general, I find my MFJ-260 unit handy in determing the lowesr SWR but I 
doubt it's accuracy when the load deviates to far from 50 ohms.

If you want accurate readings I'd take a look at the N2PKVNA:

http://www.makarov.ca/vna_payment.htm

and AIM4170:

http://w5big.com/


Here is a good write up on analyzer accuracy:

http://www.makarov.ca/download/vna/VNA%20comparisons.pdf


73,

Mike N2MS







> Hello,

>

> Has anyone made an effective AM broadcast filter (HB) for their analyzer?

>

> I have to feel that my lack of readings on the unipole may stem from AM

> interference.

> I have a station here in town, or close on 1400khz.

>

> 73's

>

> Glen K4KV


_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband

<Prev in Thread] Current Thread [Next in Thread>