Yes a real watt swr meter for 400 khz-54 mhz solution

That is a rare item, Radioham, appreciate the find!

Watching for someone to talk about how this could be used with a part 15 transmitter.

What can this meter do that can't be done without it?

This type of wattmeter, as judged by looking at the pictures of the circuit board, measures the directional currents going toward the load and reflected back from the load.  In order to get the power an assumption must be made about the load impedance.  Generally, such meters are calibrated for a 50 ohm load and the power is calculated by P = I^2x50.  In such a system, if the load resistance is not 50 ohms then the power indicated will not be accurate.

I could be missing something about this meter's design but this is a question I would ask before purchasing one.

Neil

Neil, you beat me to the punch on that one. Clearly designed for a 50 ohm load and I don't know of any AM Part 15 transmitter that's in that ballpark. However, it could still be useable for tuning and tweaking for maximum output.

I'd be curious as to connection methods, as the RF runs through the meter.  Now, I have very little experience with most Part 15 AM transmitters, but few (if any) use any sort of cable, wire, coax or feedline to an antenna. How would this physically be connected? I suppose it could be jumpered from the transmitter to the meter, then into a dummy load, but that would make it difficult to adjust for output since everything would change when connected to the antenna.

For my $$ any sort of field strength meter is a better investment. Even a cheap FSM set near your antenna would let you adjust for maximum field strength with your system set up as it would be for broadcast.  You don't need a Nems-Clarke or Potomac for relative field strength readings. 

And you know your putput is going to be less than 100mw unless someone has invented a 110% efficient transmitter!

It does look like a real quality piece of gear, however. 

TIB

iAM/ Talking House. If one switches to the external antenna jack.

i think we're stuck with using a field strength meter due to the weird impedances our TX's operate at.

Oh, yeah. Good find. I was affraid to ask other hams about this thinking it didn't exist and they'd all roll their eyes at me.

So who can we convince to design and produce a plan/kit for the kind of meter we need? Hmm.

It's a kit, but I paid them to build it

for me.

I have used it for my low power ham radio

gear.  I like it a lot.  I can't see it running

on anything other than 50 ohms, tho.  

I dealt with Oak Hills Research about 10 or

15 years ago.  They were great back then.

I also have two of their OHR-100A QRP cw

transceivers.  One is for 80 meters and the other

is for 40.  And I have the add on digital display

accessory, which plugs into either transceiver.

Nice gear.    

Brooce, Part 15 Hartford

Link appears to point to OOPS!!

http://www.ohr.com/wattmeter.htmOAK

Must have been a limited number of kits available, to which are now, all gone.

Bruce.

I have one of these meters. It's a great little wattmeter for ham QRP work but, as Neil and Tim say, it is designed for both 50 ohm source and load impedances. As such, it is not going to work with most Part 15 transmitters, unless you're operating in a 50 ohm environment. I seem to remember someone (in this forum, I think) talking about modifying his SSTRAN to work into a 50 ohm load but, for the rest of us mere Part 15 mortals, this is not the meter for us.

However, if you're a ham who does QRP, it's the bees knees. For years, this was the classic wattmeter to have for QRP'ers.

PS - Radioham's link got a bit garbled. The correct one is here - 

http://www.ohr.com/wattmeter.htm