[Amps] Dummy load varying R

[Al Kozakiewicz]

I want to thank everyone who replied on and off the list.

I never thought much about dummy loads before now.  Previously I had only used them as a safe place to dump power when repairing a radio or amplifier.  Never worried about "how accurate" they are.  The calibration process for the LP-100 meter uses bootstrapping and inference based on the assumption that it's looking into a purely resistive known load.  There's a paragraph in the manual that mentions places to obtain inexpensive surplus dummy loads.  I assumed the audience was the stereotypical cheap ham and ignored the fact that the source mentioned provides accurate loads!

I swept the MFJ load with my fairly new MFJ analyzer (yes, the irony is not lost on me) last night.  Assuming the analyzer is not totally whacked, the load starts to lose it higher than 40m.  On 15m the impedence was something like 70+10j, which is pretty crappy.  The load claims a spec of 1.1:1 SWR through 30 mHz and 1.5:1 through 650 mHz..

Now that I know what I need, I'll probably just purchase a known accurate load.  The calibration process only requires 10-50w of power, so that opens up the options quite a bit.

Thanks again to e