[Elecraft] Dummy loads for dummies

[Walter Underwood]

If you want a dummy load kit for about as much as you would pay for the box, I highly recommend the Oak Hills Research RFL-100 kit for $40.

http://www.ohr.com/rfl100.htm <http://www.ohr.com/rfl100.htm>

I used their “BNC in a UHF connector hole” kit to make my dummy load more convenient in my all-BNC shack.

http://www.ohr.com/parts.htm <http://www.ohr.com/parts.htm>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 9:41 AM, Mel Farrer via Elecraft <elecraft at mailman.qth.net> wrote:
> 
> Yes, and you should test the dummy load at the highest frequency you will be using it.  Even leaded non-inductive resistors will have a reactive component at higher frequencies.
> Frankly, I usually test them above the max frequency I intend to use it to not have any concern about error.
> 
> Mel,  K6KBE
> 
> 
>      From: Ryan Noguchi via Elecraft <elecraft at mailman.qth.net>
> To: Paul C <paulc22 at sbcglobal.net>; "elecraft at mailman.qth.net" <elecraft at mailman.qth.net> 
> Sent: Tuesday, December 27, 2016 8:16 AM
> Subject: Re: [Elecraft] Dummy loads for dummies
> 
>> I made my own dummy load last night from two 100 ohm resistors wired in parallel.  They are rated for 10 watts each and look like little bricks.  I measured the resistance at 51 ohms.  Do you think this is close enough or should I reduce it to 50?
> 
> 
> 
>> Paul KG5KXG
> 
> 
> If your impedance is really 51 ohms, that's an SWR of 1.02. If your antenna had an SWR of 1.02, would you trim it to get to 1.00, fire up your tuner, or just start operating?
> 
> However, some of those resistors that look like bricks are really coils (inductors) inside, which produce a higher impedance than the DC resistance. Under RF excitation, that dummy load may be well above 51 ohms impedance. 
> 
> 73, Ryan AI6DO  
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