KAT500: Tuning on 6m
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Howdy K3' people:
There is an 8-element yagi connected to the KAT500 for the K3 internal 6m selected 6m antenna. I set KAT500 default antenna for 6m to Ant2. On the KAT500 I can press 'TUNE' then tap K3 "XMIT" and the KAT500 will usually settle on or about 1.1:1 . Then when I .run a WSJT, Data, QSO, if the KAT500 is left in "AUTO", re-tuning will often take occupy 10 or more seconds of the time before the KAT500 finds a place it likes. Often the SWR is then in the RED or worse, FAULT. Not very often on FAULT however. Mostly what I see are SWR's around 2:1 . (KAT500 in AUTO . If I put KAT500 in BYP, the K3 often shows SWR's of 2 to 3. If left in AUTO, the mismatch is apparent in received audio. Without the KAT500, the antenna itself exhibits a 1.3 SWR consistently . The constant re-tuning or irregular attenuation due to mismatch form KAT500 is annoying. On a weak-signal QSOit means the difference from making the QSO or not decoding. -- 73 KD7YZ Bob ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Bob,
Did you QSY after tuning? If so that would explain what is happening - you may have moved out of the band segment that you used for the TUNE. See the lower half of page 9 in the KAT500 manual. You may want to 'train' your KAT500 on all segments of the 6 meter band. If you have done that already, you may need to contact support. 73, Don W3FPR On 7/14/2013 7:43 AM, KD7YZ Bob wrote: > Howdy K3' people: > > There is an 8-element yagi connected to the KAT500 for the K3 internal > 6m selected 6m antenna. > > I set KAT500 default antenna for 6m to Ant2. > > On the KAT500 I can press 'TUNE' then tap K3 "XMIT" and the KAT500 will > usually settle on or about 1.1:1 . > > Then when I .run a WSJT, Data, QSO, if the KAT500 is left in "AUTO", > re-tuning will often take occupy 10 or more seconds of the time before > the KAT500 finds a place it likes. Often the SWR is then in the RED or > worse, FAULT. Not very often on FAULT however. > > Mostly what I see are SWR's around 2:1 . (KAT500 in AUTO . > > If I put KAT500 in BYP, the K3 often shows SWR's of 2 to 3. > > If left in AUTO, the mismatch is apparent in received audio. > > Without the KAT500, the antenna itself exhibits a 1.3 SWR consistently . > > The constant re-tuning or irregular attenuation due to mismatch form > KAT500 is annoying. On a weak-signal QSOit means the difference from > making the QSO or not decoding. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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I have noticed since the last update of software I am getting more retuning
also. I had been running a test version prior to that and it did not exhibit the same retune as often. In fact I did a tune or train check prior to the contest yesterday by going thru the bands and pressing tune to make sure everything was good so I could go and point and shoot. However, the tripping of the retuning process was a distraction. I do switch antennas a lot as I have 4 choices to pick. I do understand that the KAT500 only has 3 inputs and am aware if I do the switch for the 4th antenna. If I were to describe the problem I think that something is getting lost in the memories. Maybe if the Q of the antenna is narrow maybe the bins for memory are too broad? ~73 Don KD8NNU -.- -.. ---.. -. -. ..- -----Original Message----- From: Don Wilhelm Sent: Sunday, July 14, 2013 9:56 AM To: KD7YZ Bob Cc: 'K3 List' Subject: Re: [Elecraft] KAT500: Tuning on 6m Bob, Did you QSY after tuning? If so that would explain what is happening - you may have moved out of the band segment that you used for the TUNE. See the lower half of page 9 in the KAT500 manual. You may want to 'train' your KAT500 on all segments of the 6 meter band. If you have done that already, you may need to contact support. 73, Don W3FPR On 7/14/2013 7:43 AM, KD7YZ Bob wrote: > Howdy K3' people: > > There is an 8-element yagi connected to the KAT500 for the K3 internal > 6m selected 6m antenna. > > I set KAT500 default antenna for 6m to Ant2. > > On the KAT500 I can press 'TUNE' then tap K3 "XMIT" and the KAT500 will > usually settle on or about 1.1:1 . > > Then when I .run a WSJT, Data, QSO, if the KAT500 is left in "AUTO", > re-tuning will often take occupy 10 or more seconds of the time before > the KAT500 finds a place it likes. Often the SWR is then in the RED or > worse, FAULT. Not very often on FAULT however. > > Mostly what I see are SWR's around 2:1 . (KAT500 in AUTO . > > If I put KAT500 in BYP, the K3 often shows SWR's of 2 to 3. > > If left in AUTO, the mismatch is apparent in received audio. > > Without the KAT500, the antenna itself exhibits a 1.3 SWR consistently . > > The constant re-tuning or irregular attenuation due to mismatch form > KAT500 is annoying. On a weak-signal QSOit means the difference from > making the QSO or not decoding. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Bob KD7YZ
On 7/14/2013 4:43 AM, KD7YZ Bob wrote:
> On the KAT500 I can press 'TUNE' then tap K3 "XMIT" and the KAT500 will > usually settle on or about 1.1:1 . I've never run into this problem, and I've used it a lot on 6M. There is a menu setting that may help (or cause) your problem. I don't recall the exact wording, but it establishes the upper limit on SWR for which the tuner should be in bypass mode. In other words, if the SWR is below 1.5:1, the tuner should go into bypass. > Then when I .run a WSJT, Data, QSO, if the KAT500 is left in "AUTO", > re-tuning will often take occupy 10 or more seconds of the time before > the KAT500 finds a place it likes. Often the SWR is then in the RED or > worse, FAULT. Not very often on FAULT however. A couple of suggestions though. First, the SWR through the ANT1 port is slightly lower than through the ANT2 and ANT3 port (although all three are quite low). Second, it's worth the time to check every element of the path to that 6M antenna, looking at every connector, everything in line (SWR meter, antenna patch panel, grounding panel, etc.). Make sure that EVERY connector in the path says AMPHENOL on it, and that it is wrench tight. Junk connectors are a huge cause of problems -- I'm talking PL259s, barrels, adapters, tees, elbows. Make sure that every cable-mounted connector is properly installed. Those shiny adapters sold at hamfests, and in the back of the magazines are JUNK. Make sure that none of that cable has gotten wet, which will degrade the shield. This is first-hand advice. I've personally experienced at least a half dozen problems with junk connectors over the years, and everything in my system now either says Amphenol on it, or is surplus MIL-spec stuff. When I installed my KPA500, put switches at input and output so I could run either the KPA or a legal limit Ten Tec tube amp, and had both a power meter and a scope probe in line. The resulting SWR as displayed by the KPA500 was approaching 2:1. I cleaned up the mess (installed much better switching relays, removed the power meter and scope probe, found a bad cable or two) and got the SWR down to the 1:1:1 value that I measured at the grounding panel. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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On Sunday Brown used a Straight-Key to send: -------------Original Comment------- > exact wording, but it establishes the upper limit on SWR for which the > tuner should be in bypass mode. In other words, if the SWR is below > 1.5:1, the tuner should go into bypass. I'll look it up. And, for Don, I am on one freq calling CQ. Usually on mode JT9-1. No QSY just calling every minute and sitting here awaiting a reply. >. Make sure > that EVERY connector in the path says AMPHENOL on it, and that it is > wrench tight. Mine don't. I will have to find a source to buy them. -- Best regards, Bob KD7YZ Win7-64bit + K3 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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On 7/14/2013 8:04 PM, KD7YZ Bob wrote:
> Mine don't. I will have to find a source to buy them. Major industrial distributors like Newark and Allied tend to have the best prices. RF Connection sells both good stuff and junk, but I've been unhappy with the way business was conducted, and I won't go back. It also helps to combine an order with other hams to get quantity discounts (and save on shipping). When I need connectors, I get a quantity order going with a couple of local ham clubs. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Many tuners add SWR even in bypass because the path through is not 50 Ohm. It is easy to check. Set a tuner in bypass, add a dummy load, and scan SWR. Usually SWR increases rapidly with frequency. Like 1.1 on 20m, 1.5 on 10m and 2.0 on 6m. This causes unnecessary matching when in automatic mode. The best way around this is to add a cap on the tuner input. Find that value that minimizes SWR on 6m. Usually it is 10-30pF. The cap needs to be big enough to handle power but not too big since the voltages are pretty low at low SWR (< 200V at 500W level). Ignacy, NO9E |
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On 7/16/2013 7:18 AM, Ignacy wrote:
> Many tuners add SWR even in bypass because the path through is not 50 Ohm. Actually, the fundamental cause is that those tuners use the chassis as the signal return, which adds inductance to the path. The switching relays also add inductance. A proper path would be all coax (or another form of transmission line). This doesn't matter much at HF, but it begins to be significant at 6M. I've measured the KAT500 with a VNA. I don't recall numbers, but the SWR is VERY low at 50 MHz. While adding the capacitor you mention certainly works, there's no need to do this with the KAT500. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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