[TowerTalk] MFJ 259 and the like - Accuracy?

[Ed Juge]

Tell you what, Bill...  I think they're full of crap.

Hams don't work under laboratory conditions, so we don't need megabuck lab 
instrumentation.

I have an MFJ259 and when I adjust an antenna with it, it is dead on the 
money with a Bird 43 or with the SWR calibration built into my Yaesu 
FT-1000D, Collins directional wattmeter or either of the radios in my vehicles.

The MFJ259, in my book, is one of the best pieces of ham test equipment to 
come along in a couple of decades.  I think that antenna vendor is simply 
trying to get you off his back.

Ed, W5EJ

At 10:20 AM 10/18/99 -0400, Bill Coleman AA4LR wrote:


>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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-------------------------------------------
Ed Juge
phone: 817.291.0733
email:  ed_juge@zianet.com
======================

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