[Milsurplus] ME-11A/U frequency range

[WA5CAB at cs.com]

In addition to what George said, according to the T.O. the ME-11/U (alone) 
is direct reading from 100-500 MC.  I forget the figure number but there is 
a correction chart in the manual for 30-100 and 500-600.  But it doesn't 
apply to the later three models.  It never occurred to me that the low end 
problem might be filtering.  I guess I was thinking of an SWR meter I once had 
that worked much better at 10 Meters that it did on 75.

In a message dated 6/18/2010 1:00:22 PM Central Daylight Time, 
gl4d21a at juno.com writes: 
> 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 appare
> nt 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.
> 
> 

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