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[TowerTalk] MFJ 259 and the like - Accuracy?

To: <towertalk@contesting.com>
Subject: [TowerTalk] MFJ 259 and the like - Accuracy?
From: aa4nn@juno.com (Joe L Blackwell)
Date: Mon, 18 Oct 1999 13:04:22 -0400
OK, so what does one use to try to get an antenna toward resonance?
MFJ analyzers, along with the rest, are a good tool to have in the shack.
Gets you to a starting point, anyway. Put the full power to it and check
what's going out the coax.  Nothing wrong with that.  Consider your
source, an antenna vendor?  Seems they would not like you snooping
their antenna with an analyzer.
73, de Joe AA4NN
On Mon, 18 Oct 1999 10:20:51 -0400 Bill Coleman AA4LR <aa4lr@radio.org>
writes:
> 
> 
> I've been corresponding with a certain antenna vendor's technical 
> support 
> service and they took a rather interesting position: They do not 
> accept 
> measurements from devices like the MFJ 259. Their position is that 
> such 
> devices do not possess the accuracy of properly calibrated test 
> equipment 
> (typically costing thousands of dollars). In their experience, they 
> find 
> measurements taken with a transmitter at full barefoot power and a 
> quality SWR bridge to be more reliable.
> 
> I see their point. The MFJ 259 is a rather inexpensive instrument 
> and may 
> have significant unit-to-unit variation. It is also affected by 
> strong 
> local RF fields.
> 
> My question is this -- has anyone attempted to verify the accuracy 
> of 
> these units by comparing them to thousands of dollars worth of 
> calibrated 
> test equipment?
> 
> My own crude tests indicate a usable degree of accuracy with purely 
> resistive loads up to about 50 MHz. It's hard to predict accuracy 
> with 
> reactive loads.
> 
> Comments?
> 
> 
> 
> Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@radio.org
> Quote: "Boot, you transistorized tormentor! Boot!"
>             -- Archibald Asparagus, VeggieTales
> 
> 
> --
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Vy 73, de Joe AA4NN
Eastern Top Band ARC,  Carolina DX Assn,  Carolina CW Ops,
Fairfield County Contesters, Ten-Tec only, CW only.
eeetet   ee

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