[Elecraft] Dummy Load recommendation

[Charlie T]

The secret to using wire-wound resistors for a 50Ω load is to use a lot of them in parallel as the inductance divides just as the value does for the number of resistors.
Of course, this is only reasonable if you already have a pawful to start with.  Otherwise, RF rated, big 50Ω non-inductive resistors are available from many sources.
I had a lot of 1200 Ω, 10 watt (light blue??) wire-wound resistors, so 24 of them between two pieces of G-10 made a decent HF dummy load with a good safety factor at 100 watts.

Another handy load, is one that will show 2:1 (100Ω) or 3:1 (150Ω) SWR.  It wouldn't have to take much power as you'd only be using it to check an SWR readout, etc.
I made a few out of a couple 2W resistors. They'll take reasonable power for a very short  (½ second??) check time.

73, Charlie k3ICH



-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of CUTTER DAVID via Elecraft
Sent: Tuesday, July 23, 2019 6:44 AM
To: hawley, charles j jr <c-hawley at illinois.edu>; Art Nienhouse <ka9zap at gmail.com>
Cc: Elecraft at mailman.qth.net
Subject: Re: [Elecraft] Dummy Load recommendation)

I often wonder just how useful a precision dummy load really is in the amateur service.  I picked up home brew dummy load at the club the other day.  It measured 57ohms dc and comprises 4 wire-wound resistors attached in a cluster across the end of the coax.  After lots of disparaging remarks I put it on the VNA and it didn't look at all bad out to 30MHz: nothing over 1.5:1 and no spikes or dips to indicate resonances. I'll have to do it again and make a print-out for posterity. 
I've heard that salt water in a bucket works after a fashion.  
So the question is: how good do you need it to be?
David G3UNA