[K3PZN-List] Microphonis in my MFJ antenna analyzer

[Scott, KB3JQQ]

Open it up and tighten the 3 screws holding the variable capacitor to the board. 

On Nov 28, 2017, at 09:52, Philip Karras via K3PZN-List <k3pzn-list at mailman.qth.net> wrote:

I've written an article about my using my mfj-269 antenna analyzer as a WFM transmitter and it works because in my analyzer I noticed it had microphonics causing the RF signal to be modulated in both AM and WFM, receiving NFM also seemed worked, USB ans LSB were possible but not as clearly as the AM or WFM modulations.

What I'm asking you as a group is that if you have an mfj-200 series antenna analyzer to please test it out and let me know what you find. you can use your 2-meter HT or a wide band receiver that has AM, NFM, WFM, USB, LSB, & CW modes to see what you can hear when tapping on the case of the analyzer. I was able to hear a very clear ringing produced by a microphonic transistor (IC?) that then was in the correct circuit to actually modulate the RF signal.

I also own a newer MFJ 226 Graphic Impedance Analyzer and found that it did NOT exhibit this hidden feature. I think it is probably only the tin-can cased mfj analyzers with either larger ICs or discreet transistors in the correct circuit to modulate the RF signal.

73 de KE3FL,
Phil
KE3FL at yahoo.com
AEC Carroll County OES, ORS, & VEARRL Life Member
http://cs.yrex.com/ke3fl
Karras' Corner: http://blog.solidsignal.com/list.php/author/86-PhilK
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73 de K3PZN Westminster, MD
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