Re: [Elecraft] KXB30 sensitivity better than KXB3080?
Hi, Don. Well I finally did get around to checking out the KX1 with a signal generator. Here are the signal levels at which I can barely distinguish a signal: 80m -126dBm 40m -130dBm 30m -107dBm 20m -120dBm So, 30m does appear to have a problem. I'll have to try re-tweaking the 30m trimmers, but it's interesting that 80m has much better sensitivity than 30m. The KXB3080 manual indicates that peaking the 30m trimmers affects 80m as well, so you'd think that if 30m was poor 80m ought to be poor as well. The KXB3080 manual indicates that on 30m, C3 and C4 come into play. I'm unclear if on 80m C1 and C4 remain in play, or if they are replaced by C2 and C5 (ie. are there any trimmer capacitors in play on 80m?) If both trimmers are out of play on 80m that would certainly indicate that I simply need to find a non-metallic screw-driver and peak the caps. If however the trimmers remain in play on 80m, and my 80m performance is pretty good, then perhaps either or both trimmer caps are defective. Anyway, next step is re-tweaking those caps! Thanks, Martin. VA3SIE. Martin, I would be hesitant to make comparisons based on signals on the air. The signal propagation can make a big difference. If you have a signal generator that will produce a measurable (and repeatable output, that can be used for a valid comparison. Normally, the 30 meter signals are as good or better with the 3080 option as they were with the 30 meter option. You may have a problem, but first try adjusting the 30 meter trimmers. For accuracy in adjustment, they must be adjusted with an insulated screwdriver blade - even a metallic screwdriver wrapped with tape will cause some de-tuning during adjustment and you must find the proper tuning point by trial and error. 73, Don W3FPR Martin (VA3SIE) wrote: Hi, I wonder if anyone else has an observation about the sensitivity of the KX1 on 30m with the original 30m board compared to the 30 80m board? I've noticed that signals are not as strong on 30m now with the new board. For example, the RTTY station on 10100kHz is at best a 4x5 whereas it used to be 5x9. I can only hear the strongest CW stations. 20m 40m are as good as before. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] KXB30 sensitivity better than KXB3080?
Martin, Yes, peak the trimmers on 30 meters - use a fully insulated tool (like a ceramic or hard plastic screwdriver) for the most precise tuning. If there is anything metallic on the screwdriver, your hand capacity will have an effect while tuning. If you only have a metallic tool, wrap the shaft with tape and tune a little at a time and try with each trial until it seems to be at the optimum setting. The 30 meter trimmers are not in the active part of the circuit on 80. The 80 meter receiver front end tuning is broad and the capacitors that tune it down to 80 are fixed 300 pf caps. 73, Don W3FPR Martin (VA3SIE) wrote: Hi, Don. Well I finally did get around to checking out the KX1 with a signal generator. Here are the signal levels at which I can barely distinguish a signal: 80m -126dBm 40m -130dBm 30m -107dBm 20m -120dBm So, 30m does appear to have a problem. I'll have to try re-tweaking the 30m trimmers, but it's interesting that 80m has much better sensitivity than 30m. The KXB3080 manual indicates that peaking the 30m trimmers affects 80m as well, so you'd think that if 30m was poor 80m ought to be poor as well. The KXB3080 manual indicates that on 30m, C3 and C4 come into play. I'm unclear if on 80m C1 and C4 remain in play, or if they are replaced by C2 and C5 (ie. are there any trimmer capacitors in play on 80m?) If both trimmers are out of play on 80m that would certainly indicate that I simply need to find a non-metallic screw-driver and peak the caps. If however the trimmers remain in play on 80m, and my 80m performance is pretty good, then perhaps either or both trimmer caps are defective. Anyway, next step is re-tweaking those caps! Thanks, Martin. VA3SIE. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] KXB30 sensitivity better than KXB3080?
Hi, I wonder if anyone else has an observation about the sensitivity of the KX1 on 30m with the original 30m board compared to the 30 80m board? I've noticed that signals are not as strong on 30m now with the new board. For example, the RTTY station on 10100kHz is at best a 4x5 whereas it used to be 5x9. I can only hear the strongest CW stations. 20m 40m are as good as before. I don't know how good 80m is. It works but I have no basis for comparison. Any suggestion where to start trouble-shooting? I assume the problem will be in the main SMD-loaded board rather than the T2 changes or the LPF-1 board, since those other parts of the mod would affect 20m/40m performance and TX performance... which seems fine. All the tests in the assembly manual passed, the correct voltages were present at the correct times. I'll repeat those tests to make double sure. I suppose then I will double-check all the connections to the main KX1 board from the KXB3080 board. Any other suggestions? Anyone else had a problem? Cheers 73 Martin. VA3SIE. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] KXB30 sensitivity better than KXB3080?
Martin, I would be hesitant to make comparisons based on signals on the air. The signal propagation can make a big difference. If you have a signal generator that will produce a measurable (and repeatable output, that can be used for a valid comparison. Normally, the 30 meter signals are as good or better with the 3080 option as they were with the 30 meter option. You may have a problem, but first try adjusting the 30 meter trimmers. For accuracy in adjustment, they must be adjusted with an insulated screwdriver blade - even a metallic screwdriver wrapped with tape will cause some de-tuning during adjustment and you must find the proper tuning point by trial and error. 73, Don W3FPR Martin (VA3SIE) wrote: Hi, I wonder if anyone else has an observation about the sensitivity of the KX1 on 30m with the original 30m board compared to the 30 80m board? I've noticed that signals are not as strong on 30m now with the new board. For example, the RTTY station on 10100kHz is at best a 4x5 whereas it used to be 5x9. I can only hear the strongest CW stations. 20m 40m are as good as before. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
