Got my T1 kit last night, got the parts inventoried, and got up to where
I need to start winding the toroids... I did notice one thing on the schematic that left me puzzled though, there doesn't seem to be any DC return path for the relay coils. Am I missing something? 73, Ross N4RP -- FCC Section 97.313(a) “At all times, an amateur station must use the minimum transmitter power necessary to carry out the desired communications.” ______________________________________________________________ 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 |
Ross,
You are looking too hard! Most of the Elecraft tuners use the same technique - the selected relay is activated and the return path flows through all the rest of the other relay coils - there is not enough current through any one coil to activate them, and it works quite well - one more piece of "magic" that can be done using PICs. 73, Don W3FPR On 3/4/2011 1:30 PM, Ross Primrose N4RP wrote: > Got my T1 kit last night, got the parts inventoried, and got up to where > I need to start winding the toroids... I did notice one thing on the > schematic that left me puzzled though, there doesn't seem to be any DC > return path for the relay coils. Am I missing something? > > 73, Ross N4RP > ______________________________________________________________ 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 |
OK, so I finished the build yesterday, and today, after I built another
BNC-PL259 cable so I could hook it up, I did the performance tests. Everything seems OK, except the transmit power display tests. The T1 shows the correct power level, but the K3 indicates at >10:1 SWR during the power measurement. Bypass mode works fine, if I put the T1 in bypass and hit the tune switch on the K3 the dummy load gives a 1:1 SWR, it's only a problem when trying to display power.... Ideas? 73, Ross N4RP On 3/4/11 2:26 PM, Don Wilhelm wrote: > Ross, > > You are looking too hard! Most of the Elecraft tuners use the same > technique - the selected relay is activated and the return path flows > through all the rest of the other relay coils - there is not enough > current through any one coil to activate them, and it works quite well > - one more piece of "magic" that can be done using PICs. > > 73, > Don W3FPR > > On 3/4/2011 1:30 PM, Ross Primrose N4RP wrote: >> Got my T1 kit last night, got the parts inventoried, and got up to where >> I need to start winding the toroids... I did notice one thing on the >> schematic that left me puzzled though, there doesn't seem to be any DC >> return path for the relay coils. Am I missing something? >> >> 73, Ross N4RP >> -- FCC Section 97.313(a) “At all times, an amateur station must use the minimum transmitter power necessary to carry out the desired communications.” ______________________________________________________________ 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 |
Ross,
Who knows what the L and C values are that are in your T1 until you do a TUNE. The incication of a low SWR when the T1 is in bypass indicates that there is residual reactance when in non-bypass. Doing a TUNE should straighten things out. The settings are remembered by band, so do a TUNE on each band. 73, Don W3FPR On 3/6/2011 8:22 PM, Ross Primrose N4RP wrote: > OK, so I finished the build yesterday, and today, after I built another > BNC-PL259 cable so I could hook it up, I did the performance tests. > Everything seems OK, except the transmit power display tests. The T1 > shows the correct power level, but the K3 indicates at>10:1 SWR during > the power measurement. Bypass mode works fine, if I put the T1 in > bypass and hit the tune switch on the K3 the dummy load gives a 1:1 SWR, > it's only a problem when trying to display power.... > > Ideas? > 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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