KAT3 losses vs KAT3A
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The new KAT3A tuner has a relay bypass that results in lower losses. What are the losses in the old KAT3 without a relay? And do the losses occur when using a matched antenna with the old KAT3 NOT engaged. The statement: "Lower loss on bands where matched antennas are used." is a little cryptic to me with respect to the KAT3A version.
Are the losses in the old version present irrespective of the tuner being inline or not? Clarification would be appreciated. 73 Bill, K4CIA ______________________________________________________________ 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 Message delivered to [hidden email] |
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> On May 19, 2015, at 8:30 AM, Bill McDowell <[hidden email]> wrote: > > The new KAT3A tuner has a relay bypass that results in lower losses. What are the losses in the old KAT3 without a relay? And do the losses occur when using a matched antenna with the old KAT3 NOT engaged. The statement: "Lower loss on bands where matched antennas are used." is a little cryptic to me with respect to the KAT3A version. > > Are the losses in the old version present irrespective of the tuner being inline or not? > > Clarification would be appreciated. > Eric (or maybe one of the other Elecraft team) addressed this a few days ago. Apparently the KAT3 simply goes to a calculated “50 ohm match” position when you put it in bypass, e.g., it’s still in-line, it’s just set for a 50 ohm match. Only there may be times when it does not get to the correct position, so if you’re not using an external tuner the KAT3’s position might not be optimum for a resonant antenna presenting a 50 ohm load. The KAT3A uses a hard relay bypass to get around this. I can’t say I’ve ever seen an issue related to this with my resonant antennas, but others may have. I’d think the losses would be small (low tenths of dB) in any case, and most likely not worth replacing the KAT3 unless you’re buying a new radio. YMMV Grant NQ5T ______________________________________________________________ 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 Message delivered to [hidden email] |
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> I’d think the losses would be small (low tenths of dB) in any case, > and most likely not worth replacing the KAT3 unless you’re buying a > new radio. The "Tuner" portion of TLW calculates the loss in an L network (the KAT3) in the low *hundredths* of a dB for 50 Ohms to near 50 Ohms (50:50 is undefined). Wayne confirmed that was accurate for the KAT3. > Only there may be times when it does not get to the correct position, > so if you’re not using an external tuner the KAT3’s position might > not be optimum for a resonant antenna presenting a 50 ohm load. If your K3/KAT3 shows high SWR when working into a 50 Ohm load with the KAT3 bypassed, the easy solution is to enable the tuner, tune into a dummy load and then bypass the tuner. That process will reset the "bypass" settings. 73, ... Joe, W4TV On 2015-05-19 10:09 AM, GRANT YOUNGMAN wrote: > >> On May 19, 2015, at 8:30 AM, Bill McDowell <[hidden email]> >> wrote: >> >> The new KAT3A tuner has a relay bypass that results in lower >> losses. What are the losses in the old KAT3 without a relay? And >> do the losses occur when using a matched antenna with the old KAT3 >> NOT engaged. The statement: "Lower loss on bands where matched >> antennas are used." is a little cryptic to me with respect to the >> KAT3A version. >> >> Are the losses in the old version present irrespective of the tuner >> being inline or not? >> >> Clarification would be appreciated. >> > > Eric (or maybe one of the other Elecraft team) addressed this a few > days ago. > > Apparently the KAT3 simply goes to a calculated “50 ohm match” > position when you put it in bypass, e.g., it’s still in-line, it’s > just set for a 50 ohm match. Only there may be times when it does > not get to the correct position, so if you’re not using an external > tuner the KAT3’s position might not be optimum for a resonant antenna > presenting a 50 ohm load. The KAT3A uses a hard relay bypass to get > around this. I can’t say I’ve ever seen an issue related to this > with my resonant antennas, but others may have. > > I’d think the losses would be small (low tenths of dB) in any case, > and most likely not worth replacing the KAT3 unless you’re buying a > new radio. > > YMMV > > Grant NQ5T > > ______________________________________________________________ > 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 Message delivered to > [hidden email] > 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 Message delivered to [hidden email] |
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