[Milsurplus] ME-11A/U frequency range

[gl4d21a at juno.com]

Jim:

I've had one of those for many years, and finally bought a manual from Robert last year.  Here is what I have determined.  The meter will read power down to DC, but at lower frequencies, as in using power line frequency for calibration, additional filter capacitance must be added across the meter circuit.  I have not checked, but I suspect some additional filtering would also be needed for HF (3-30 MHz).  The easy way to tell is to shunt a good quality 0.5 Mf or so across the meter while applying power around 3.7 MHz.  If the meter moves upscale, it needs the capacitor, or maybe evan a larger one.  Experiment, but be careful where you discharge the capacitor, avoid blowing the diode.  

There are several correction curves in the manual, as best I could tell, they relate to temperature compensation in the metering circuitry, and not to any frequency sensitivity.  The high frequency end is limited by an apparent self-resonance in the 600 MHz range, causing the impedance to go out of specification.  

I was concerned about the level of the coolant, as mine sloshes.  Apparently that is normal, and as long as the resistor is fully immersed, it is 50 ohms.  Or 52 or whatever it is marked.  Don't use it upside down, or standing on end, as this uncovers a portion of the element, changing the impedance and possibly causing overheating of that part of the load.

73,
George
W5VPQ

---------- Original Message ----------
From: Jim Whartenby <antqradio at sbcglobal.net>
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] ME-11A/U frequency range
Date: Fri, 18 Jun 2010 10:10:57 -0700 (PDT)

Is one to infer that you and use it to measure at lower frequencies with a correction factor?



----- Original Message ----
From: "WA5CAB at cs.com" <WA5CAB at cs.com>
To: jmfranke at cox.net; milsurplus at mailman.qth.net
Sent: Fri, June 18, 2010 11:36:05 AM
Subject: Re: [Milsurplus] ME-11A/U frequency range

John,

ME-11/U is different but for ME-11A/U through C/U, direct reading from 30 
to 600 MC/s.

In a message dated 6/18/2010 11:25:07 AM Central Daylight Time, 
jmfranke at cox.net writes: 
> 
> Anyone happen to know the frequency range of the ME-11A/U RF Wattmeter.
> 
> Thanks,
> 
> John  WA4WDL
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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