[K3] [Elecraft] [k3] Wattmeter calibration
Finally I got round to checking the wattmeter calibration as I've felt it's been giving out power levels below what the wattmeter on the front panel reports ever since I've had it. First alerted when my Acom 1000 seemed to giving low output until I saw the amp's input reporting a significantly lower driving power eg 35w as against a K3 setting of 45w into a dummy load. Also 2 independant power meters seemed to agree even though admittedly they weren't lab standard. So I did the configuration while measuring voltage across a dummy load with my 40MHz 'scope and found I needed to wind the WMTR HP setting way down to minimum (010) to get the power up to 50 watts on the 'scope (and yes I did remember the RMS to peak conversion ;-). Seeing that the default setting is 100 I thought I might ask others what setting seems to be the norm. Needless to say I've not noticed anything odd about running 80 or 85 watts instead of 100 these past few months but (wrong) numbers do have a habit of bugging you eventually 73, Stewart Rolfe, GW0ETF (K3 145) -- View this message in context: http://www.nabble.com/-k3--Wattmeter-calibration-tp18155295p18155295.html Sent from the [K3] mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [K3] [Elecraft] [k3] Wattmeter calibration
GW0ETF wrote: Finally I got round to checking the wattmeter calibration as I've felt it's been giving out power levels below what the wattmeter on the front panel reports ever since I've had it. First alerted when my Acom 1000 seemed to giving low output until I saw the amp's input reporting a significantly lower driving power eg 35w as against a K3 setting of 45w into a dummy load. Also 2 independant power meters seemed to agree even though admittedly they weren't lab standard. So I did the configuration while measuring voltage across a dummy load with my 40MHz 'scope and found I needed to wind the WMTR HP setting way down to minimum (010) to get the power up to 50 watts on the 'scope (and yes I did remember the RMS to peak conversion ;-). Seeing that the default setting is 100 I thought I might ask others what setting seems to be the norm. Needless to say I've not noticed anything odd about running 80 or 85 watts instead of 100 these past few months but (wrong) numbers do have a habit of bugging you eventually I was a bit worried about doing this setting as I didn't have any accurately calibrated wattmeter other than my home made QRP ones. In the end I used my DL1 module. It didn't seem to mind handling 50W for the few seconds needed to get the reading on my voltmeter. I think the lowest I needed to wind the setting down to was somewhere in the 70s. If I'd had to go down as low as 10 I would have worried that there was something wrong with my calculations. - Julian, G4ILO K3 s/n: 222 K2 s/n: 392 G4ILO's Shack: www.g4ilo.com KComm for K2/K3: www.g4ilo.com/kcomm.html -- View this message in context: http://www.nabble.com/-k3--Wattmeter-calibration-tp18155295p18155740.html Sent from the [K3] mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[K3] [Elecraft] [k3] Wattmeter calibration
I calibrated my K3 power meter against a calibrated (bought assembled calibrated) LP100 that is only a few months old. My WMTR HP calibration is 062. You mentioned the Acom 1000, I also have one of those. On mine (and it was mentioned in one of the reviews as well), the digital power level displayed on the Acom is over optimistic by quite a margin. From memory 1 KW on the display was more like 850 or 900 Watts from the rear panel, if I was being cynical I would suggest it helps sell amplifiers! 73 Dave, G4AON K3/100 #80 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
