Stan, It sounds like you assume the 48-inch jumper is OK. That it first think I would swap out to determine if it is affecting your readings. Bad cables sneak up and "bite me in the rear" way too often (because I assume they are good). Or If you can connect the K2 thru the same 48-inch cable used with the K3, that will be a better comparison.
If you have a dummy load, directly connect it to the K3 and read the SWR. If you have two dummy loads connect them to the K3 with a coaxial tee. This will present a 25-ohm load (VSWR=2:1). If the K3 SWR reads significantly different using the dummy loads then you have a problem in the K3. That being said I never depend on internal SWR meters. When I want to know exactly then its either the Bird43 power meter or directional couplers and calculate VSWR from forward and reflected readings. 73, Ed - KL7UW ------------------------------ Message: 2 Date: Thu, 31 Mar 2011 12:19:44 -0400 (EDT) From: stan levandowski <[email protected]> Subject: [Elecraft] K3 SWR Readout Accuracy Question To: [email protected] Message-ID: <4097185.180346.1301588384528.javamail.sjl...@mstr20.srv.hcvlny.cv.net> Content-Type: text/plain; charset=UTF-8; format=flowed; delsp=no On my newly assembled kit K3/10 without the internal ATU, I've noticed that the SWR readouts are "higher" than those on my K2 which agrees with my analog inline meter. Into a 50 ohm dummy load all three readings are 1.0:1, but on an actual antenna the readings differ. For example, where my K2 and the analog meter read 1.4:1, the K3 says 1.9:1. this variance increases as the SWR increases and decreases as the actual SWR decreases, hence the agreement among all three measures on 1:1 when operating into a dummy load. All readings taken at 5 watts, same antenna, same SG-237 autocoupler, same cable routings, and the internal ATU in the K2 bypassed. The only variable is the actual 48"coax jumper going from the K3 to the patch panel. I just finished the K3 yesterday so I am just a K3 beginner. However I could find nothing in the manual about SWR calibration. Any pointers would be appreciated. Other than this, everything appears to be working great and the K3 DSP is fabulous. Stan WB2LQF K3 #5244 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep [email protected] ====================================== ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
