Tnx Dick, Then I guess it is the K3 MCU firmware code that is "ramping up the power" because I see it doing it on the K3 front panel display as the Calibrate routine is running. It approaches 5 Watts from below, takes a fraction of a second to get there. Until it gets there, the SWR reading on the K3 screen is 1.1. When it does get there (e.g., to 5 Watts), the SWR reading changes to 1.0. Then the K3 stays in transmit for about a second or two before moving on to the next frequency. At 50 Watts, the ramp-up time (if any) is so quick that it doesn't have time to show up on the K3 front panel display.
I guess I was thinking that the K3 Utility was doing more than it was doing. Thanks for the description. It must be a gas to write this stuff and have it work so well. Wish the code were public so we could admire it. 73, Oliver Johns W6ODJ On 6 Jan 2010, at 1:16 PM, Dick Dievendorff wrote: > The K3 Utility doesn't "ramp up the power" during the Tx Gain calibration. > It sets the power to exactly 5 watts, and the K3 MCU firmware code performs > calibration at that power level (and also at exactly 50 watts). > > Tx Calibration also sets TUN PWR to "Normal" and restores your setting > afterward. > > Glad it's working for you now! > > 73 d Dick, K6KR > > > -----Original Message----- > From: O. Johns [mailto:[email protected]] > Sent: Wednesday, January 06, 2010 12:04 PM > To: Dick Dievendorff > Cc: Elecraft; Gary Surrency > Subject: Re: [Elecraft] K3: Strange SWR reading > > Gents, > > Problem solved, or at least worked around. > > I had the TUNE PWR set to 4 Watts. But my K3 SWR reading is inaccurate > below 5 Watts. I set TUNE PWR to 7 Watts and now the problem is solved. > With the DL1 connected to Ant 1, and KAT3 on BYPASS, pressing TUNE now gives > 1.0 on all bands. > > Here are the readings at various powers with my K3 in the 40 meter band: > 1 Watt ---> no reading > 2 Watt ---> 1.2 > 3 Watt ---> 1.1 > 4 Watt ---> 1.1 > 5 Watt ---> 1.0 > 6 Watt and above ---> 1.0 > > 73, > > Oliver Johns > W6ODJ > > P.S. The reason the Elecraft K3 Utility seemed to be adjusting the SWR > reading was that it was ramping up the power to 5 Watts. As it passed 3 and > 4 Watts, it showed 1.1; when it reached 5 Watts it showed 1.0. > > > On 5 Jan 2010, at 5:23 PM, O. Johns wrote: > >> Dear Dick, >> >> I posted this problem on the reflector some time back, but noone picked up > on it, so I'll try again. This is a before and after story and has me > puzzled. >> >> BEFORE: I connected DL1 dummy load to Ant 1 using only a BNC-MtoM and a > PL259-FtoF (no coax at all, just small straight-through adapters). I set > the KAT3 to BYPASS. I pressed TUNE and saw 1.0, on all bands. Fine, this > is what I expect. Also, using my link-coupled external tuner with the > antenna connected (I seldom use the KAT3), I was able to adjust to 1.0 on > all bands (except 6 meters). >> >> AFTER: After the first time I ran the "Calibrate Transmitter Gain" > routine from the Elecraft K3 Utility, I pressed TUNE with the DL1 still > connected and saw a SWR reading of 1.1 on all bands, not 1.0 as before. > Also, when I use my external tuner, the lowest SWR I can obtain now is 1.1, > not 1.0 as before. >> >> WHY? >> >> I just upgraded the K3 (#1741) with all current mods and the new DSP > board. So, I re-calibrated everything. Same result re the 1.1 SWR reading. > >> >> Here is what happens: >> >> I attach the DL1 and set KAT3 to BYPASS as per the instructions. I run > through the steps and click on Calibrate in the 5 Watt page. The > calibration routine runs to completion successfully. At every frequency I > see on the K3 front panel readout the following two-step sequence: >> - The frequency to be used >> - The numbers 1.1 which quickly change to 1.0 >> It seems as if the software is adjusting something to get to 1.0 for the > SWR. What? I don't hear any clicks so doubt it is adjusting any toroids or > capacitors the ATU. Maybe it is adjusting the final transistor bias? >> >> After this calibration, pressing TUNE with the DL1 still connected and the > KAT3 still in BYPASS, I see 1.1 SWR. >> >> I then did the routine again, but this time doing the 5 watt and then the > 50 Watt Calibration (the DL1 doesn't get very hot due to the short duty > cycle). At 5 Watts, the result is the same as above. At 50 Watts, I see > the following for each frequency step: >> - The frequency to be used >> - The number 1.0 >> This time it doesn't seem to be adjusting anything. Maybe that was > already done at 5 Watts? It just starts out at 1.0 and stays there. >> >> After this calibration, pressing TUNE with the DL1 still connected and the > KAT3 still in BYPASS, I see 1.1 SWR. >> >> So, what is going on? It seems to me that if I adjust the transmitter > using DL1 as the reference for 1.0 SWR, then pressing TUNE with the DL1 > attached and KAT3 still in BYPASS should also give 1.0. >> >> So, two question: >> (1) What is the software adjusting that affects the SWR shown on the K3 > front panel display? >> (2) Why is the end result a lowest SWR of 1.1 instead of 1.0? >> >> Thanks for any information. >> >> Oliver Johns >> W6ODJ >> >> PS: Configuration information: >> K3 #1741, KPA3, KAT3, KBPF3, KTCXO3-1, KXV3, K3DSPUPGD upgrade, REMIOUPGD > upgrade, all Elecraft-recommended user mods up to 1 Jan 2010 done, and no > other mods done. No KRX3. No KXV3A upgrade. >> >> >> >> >> ______________________________________________________________ >> 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 >> > > ______________________________________________________________ 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
