Watt meter plus

[k7mdo]

Here is the other day's find at the surplus house.  It appears to be a commercial grade 500 watt wattmeter.  I can't trace out the circuit in the little transducer box due to glyptol (sp?) or whatever they used to "fix" the transducer in place.  The exterior circuitry is simply a two way toggle, momentary in one direction.  There two 10k pots that appear to set, maybe, a zero in one direction or full scale and maybe the same with the switch in the other position.  I just found a couple of "N" to BNC convertors so I can insert it between the Viking and the dummy to see what I get. 

Has anyone seen one of these?  It is definitely not homebrew.

73, Tom

[WBear2GCR]

Looks like small toroids in the goop?

Also the pots look to be Asian mfr, maybe Japanese... which is a little odd.

Perhaps the meter and the unit are spliced together by someone?
Probably this is an SWR meter of some sort.
A bit of sleuthing and you can likely find a circuit or two that uses toroids that will match this one.

I've never seen one like this myself.

[KA3EKH]

Just looking at it don’t think I would want to run five hundred watts thru it for long, also would think it intended for lower frequencies. I have a five hundred watt toroid type watt meter that was designed for use on the old VLF NDB band and it’s good up to around 7 to 10 MHz
Think RF Sealing systems (Dielectric Welding) for plastics are low frequency and high power, maybe that’s from one of them?

[k7mdo]

I finally sat down and noodled out the wiring of the external circuit...  I would have already fed a little RF through it but had to wait for a hamfair (Seaside, Oregon which was great) to get a couple of UHF to N connectors...  I will see what happens with the Viking II and report...  I need to put it in a chassis as soon as I can find one of the right size.

I am not sure but I imagine the MOM position of the thing will be for setting zero or zeroing the reflected power and then the ON position might show forward power during transmit?? Or?

73 Tom