[Milsurplus] RE2/ARC5

[Mike Feher]

I already pointed that out. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
908-902-3831

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net <milsurplus-bounces at mailman.qth.net> On Behalf Of hwhall--- via Milsurplus
Sent: Monday, June 16, 2025 1:21 AM
To: Charlie L. <mjcal79 at gmail.com>; Mark K3MSB <mark.k3msb at gmail.com>
Cc: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] RE2/ARC5

There must be a mistake or typo about that meter internal resistance.

Wayne
WB4OGM

On Saturday, June 14, 2025 at 05:25:37 PM MDT, Mark K3MSB <mark.k3msb at gmail.com> wrote: 

Hi Charlie

I have a new, probably never used,  BC-442-A Relay unit.

I measure 5 mA FS meter deflection with an internal meter resistance of 0.033 ohms.

These were measured by the usual means of a series resistance to give FS deflection then a shunt to give half-scale deflection.

Across the meter leads of the thermocouple, I measure 1 ohm (meter disconnected).
Across the other leads I measure about 0.7 ohms (wires also disconnected).
There lead resistances were subtracted out to give the above two measurements.

Remember, the meter face reads Antenna Current Indicator -- there are no units given.  

As mentioned in other posts, at home I go through a 4:1 UNUN then through an air variable series capacitor (an old HT-37 cap with some rotors removed...) to get to 50 ohms to feed my home antennas.

Sometimes I see my BC-442 hit '2", other times it just budges a little, yet my wattmeter shows 40 to 50 W out.  I think the current distribution depends upon what antenna you are using and the matching network.

LIke others have said, one can ignore the relay meter reading when you have a wattmeter in line further downstream.   

As posted a few weeks ago, I experimented with a 45 foot random wire antenna as that is what the B-24 used, but I did not have a counterpoise (I didn't think about the fuselage being the counterpoise.....).
I plan to recreate that later this month with an insulated counterpoise and see if that has any impact on the relay meter movement.

I hope this helps.

73 Mark K3MSB





On Fri, Jun 13, 2025 at 3:46 PM Charlie L. <mjcal79 at gmail.com> wrote:
> I have 2 RE2 antenna relay/RF ammeters, both meters seem inop.  I ohmed out the thermocouple free of external connections and are identical.  The meters have continuity, but with a Simpson 260 on RX1, only a flicker of movement.  I have a note that says these are 6MA movements, guessing that is DC out of the thermocouple not RF.  My TCS gear, when tuned up to 50 ohms gives an amp reading coincident with RF out,  I would have expected these meters to do the same.  I get 50 watts out of a BC696A into 50 ohms, using the RE2 and the 50PF series cap in the back of it to feed 50 ohm coax, so I hoped to see 1 amp, but got nothing.  I also tried making a resistive load of 10 ohms to simulate a normal aircraft ant load of between 5-15 ohms, and still no meter reading.  What is the secret to this RF ammeter if it is not broken?
> 
> Charlie in NC
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