[Milsurplus] RE2/ARC5

[Ray Fantini]

Been following this only slightly, don’t know what you are all talking about? Thought this all had to do with relationship between what an antenna current meter is telling you and how well the antenna is working.  First about antenna current meters, don’t know what others do but back in the old days in broadcasting we would test antenna current meters at 60 cycles using a light bulb. A 100 watt light bulb will draw around three quarters of a amp. A 630 watt 120 volt lamp (Top Beacon) sucks down just over 5 amps, that’s back when we use to use and have base current meters at each tower in a AM site along with a Common Point meter that let you know what you were feeding the antenna network. A 5kW broadcast station usually has a common point of 10.5 amps The meters would get old, out of calibration and often damaged by lightning so you had to check them  annually. Around the eighties and nineties everyone replaced there analog meters with Delta loops that are way better and not in need of checking.
Yes its true current and voltage are distributed acrost the transmission line and the antenna and where the base current meter lives will have an effect on the reading. In broadcasting the common point was at the transmitter and base current meters were at the base of the antenna, most AM stations had the base current meter on a slide plate where you were able to insert in in line when you did the reading and pull it out of the circuit to protect it when not in use. Back in the dinosaur days when broadcasters kept logs you had to do a base current reading every three hours.
Somehow dint think where you have the meter mounted by the radios will make that big of a difference within reason.
My first inclination would be to test your meter with a light bulb at sixty cycles and find out if your thermocouple and bridge rectifier in the meter are still good, the second issue would be not to rely on the meter that much. Its anecdotal but I have found that most of the old WW2 circuits for antenna current are only active when feeding short antennas  and not as good as something like using a field strength meter. Life is way better being concerned about plate current of the PA and the efficiency of the match between the radio and the antenna then obsessing  about the peak current meter. Think the T/R relay is not an issue.
Get yourself a ME-61 and that way you can see what’s happening.
Another thing that I do that probably no one else will agree with. I have gone to setting all my larger beyond back pack radios for a 50 Ohm load so they can be tested on the bench or connected to a antenna for use in the shack. This way you can use coax between the radios and a external antenna tuner at the antenna and that works for me. Imagine lots of the WW2 people will be like that’s not using it as intended but at the end of the day so what? That’s what works for me. Besides think that back in the 1967 ARRL Handbook they tell you to remove the roller inductor on a ARC-5 and that the tank secondary is around fifty Ohms and you can go directly to that with coax. Don’t look as cool as the open wire and beads and all that sort of stuff, but works real well.
Least that’s what I think, but certain there are others who may have differing opinions.

Ray F/KA3EKH





From: milsurplus-bounces at mailman.qth.net <milsurplus-bounces at mailman.qth.net> On Behalf Of kgordon2006
Sent: Monday, June 16, 2025 10:22 AM
To: Mike Feher <n4fs at eozinc.com>; 'Mark K3MSB' <mark.k3msb at gmail.com>
Cc: 'Charlie L.' <mjcal79 at gmail.com>; milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] RE2/ARC5


Mark: I must agree with Mike here. Your measurement result is very unlikely, but at this point, I cannot tell what is wrong.

The fact that you got two quite different results from two supposedly near-identical meters is "interesting".

The technique you used, i.e. two resistors, etc. is certainly correct.

Ken W7EKB



Sent via the Samsung Galaxy S21 5G, an AT&T 5G smartphone


-------- Original message --------
From: Mike Feher <n4fs at eozinc.com<mailto:n4fs at eozinc.com>>
Date: 6/16/25 07:09 (GMT-08:00)
To: 'Mark K3MSB' <mark.k3msb at gmail.com<mailto:mark.k3msb at gmail.com>>
Cc: "'Charlie L.'" <mjcal79 at gmail.com<mailto:mjcal79 at gmail.com>>, milsurplus at mailman.qth.net<mailto:milsurplus at mailman.qth.net>
Subject: Re: [Milsurplus] RE2/ARC5

Mark –

It still sounds unlikely to me. Did you try to measure the total current using a current probe or another milliamp meter in series, like 10 MA full scale? I recently measured the internal resistance of a 0 to 1 ma meter using a bridge/Kelvin technique to minimize the current, and measured around 340 ohms. 73 – Mike

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