[Milsurplus] RE-2 meter

[hwhall@aol.com]

In Elden's data, isn't that 0.75A thru the thermocouple heater & not thru the meter, though? The RF current never goes thru the meter movement, only thru the heater part of the thermocouple. 

I think we'd all been trying to figure out how the meter movement had such a low resistance but perhaps it was only the heater instead.

Wayne
WB4OGM

On Tuesday, June 17, 2025 at 07:11:35 PM MDT, Mark K3MSB <mark.k3msb at gmail.com> wrote: 

Thanks Elden.

19.5 mV with a 3 ohm internal resistance yields 6.3 mA FS, which is close to my 5 mA measured on two different meters.  Being 85 years old, I find the difference understandable.

The markings on the Thermocouple do indeed indicate a max of 0.75 A:

I have a problem with the chart.   With a 3 ohm internal resistance,  here's the voltage across the meter with the indicated current values:

With a meter reading of 1,  the voltage across the meter is 18X the FS value of 19.5 mV.

If 19.5 mV is FS, and that's with 0.75 A through the meter,  then the internal resistance is 0.026 ohms, which is in the ballpark of my value of  0.033 ohms. 

73 Mark K3MSB





On Tue, Jun 17, 2025 at 5:53 PM elden meyer via Milsurplus <milsurplus at mailman.qth.net> wrote:
> Good Afternoon, 
> 
> In the June 1963 Surplus issue of 73 magazine Roy Pafenberg writes about the antenna relay. 
> 
> He gives this data: 
> 
> meter only - 3 ohms DC resistance, 19.5 millivolts full scale 
> 
> with thermocouple - 
> reading , RF amps 
> 1  , 0.12
> 2  ,  0.18 
> 3  , 0.22 
> 4  , 0.26 
> 5  , 0.32 
> 6  , 0.37 
> 7  , 0.43 
> 8  , 0.50 
> 9  , 0.59 
> 10 , 0.75 
> 
> Elden 
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