On Tue, Jun 22, 2004 at 09:32:30AM -0400, Eric Ward wrote: > In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for two) at > the Shack and soldered it to a male BNC--I figured this would make a > serviceable QRP dummy load. The resistor checked out at 50.0 ohm on my DMM. > > When I hooked this to my KX1 and went through the ATU alignment procedure > (nulling C9, etc), I only get an apparent out put of about 0.3W (according to > the display on the radio). Ditto when I tune my G5RV--I get to 1:1.1, but > with only 0.3W. (This antenna/feedline system is tunable by my LDG Z100 to > 1:1; see below.) > > I had previously gone through the ATU alignment using, instead of a dummy > load, the G5RV routed through the external match (the LDG Z100) tuned for > that frequency. I figured that would be pretty close to 50 ohm, since it > achieves an apparent 1:1 on that freq with my Icom 706 rig. > > When I use the tuned G5RV as a "dummy load" and go through alignment, I get > what appear to me more reasonable values--i.e. when I subsequently tune the > same antenna with the KX1 ATU, I get 4.3W and SWR of 1:1.6. > > So something funky is going on and I cannot figure it out. Is there some > bloody obvious reason why the 10W resistor is not a good dummy load? Is > something else wrong with my rig, which otherwise is nominal in all respects? > (BTW, I have R4 maxed out clockwise.) I do not have a wattmeter, so I > cannot independently check output with and without the ATU installed, but the > rig is transmitting on 40 and 20m. > > Thanks for any ideas...
Is it a non-inductive resistor? If not, it probably won't be anywhere near 50 ohms at R.F. Bob, N7XY _______________________________________________ Elecraft mailing list Post to: [email protected] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
