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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|