KX1 - very quiet on 30m and 20m
Locked
 
|
I've just completed a KX1 build with the 80/30m option and auto atu.
It works on all bands but 30m and 20m require the volume control to be fully clockwise and even then it's quiet. I've carried out the recommended checks and everything appears to be fine. Having read the previous posts on 'low audio' there's an element of subjectivity regarding what this means. Does anyone know of a definitive measurement I can make to see if this radio is working as well as it should? For example, I have the XG1 and can inject a 14.060 MHz signal at 1 microvolt or 50 microvolts. With the bandwidth set to maximum, what level of signal should I expect on the input or output of the audio amplifier, or at any other point in the circuit? Any advice gratefully received. Bob, G3YIQ ______________________________________________________________ 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 |
Re: KX1 - very quiet on 30m and 20m
|
|
Bob,
I can't give you a measurement number right away, I do not have a working KX1 here at the moment, but that value may be possible tomorrow or Friday. If you do not hear quite a loud signal with the 50 uV output from the XG2 (or XG1 with a 20 meter crystal) - with the RF Gain at full clockwise and the AF Gain between 25 and 35% of rotation, then there is something wrong. How is the transmit power output? If that is OK, then the low pass filter is likely OK, and you might want to look at T2. The KX1 audio is not super strong, and having good volume does depend on using sensitive headphones. If your headphones do not have an sensitivity rating greater than 108 dB/mW, then your headphones may be the major problem, see the KX1 manual page 62. 73, Don W3FPR Bob Jones wrote: > I've just completed a KX1 build with the 80/30m option and auto atu. > > It works on all bands but 30m and 20m require the volume control to be fully clockwise and even then it's quiet. I've carried out the recommended checks and everything appears to be fine. > > Having read the previous posts on 'low audio' there's an element of subjectivity regarding what this means. > > Does anyone know of a definitive measurement I can make to see if this radio is working as well as it should? > > For example, I have the XG1 and can inject a 14.060 MHz signal at 1 microvolt or 50 microvolts. With the bandwidth set to maximum, what level of signal should I expect on the input or output of the audio amplifier, or at any other point in the circuit? > > Any advice gratefully received. > > Bob, G3YIQ > > > > > ______________________________________________________________ > 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 > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.0.238 / Virus Database: 270.11.18/2009 - Release Date: 03/18/09 07:17:00 > > 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 |
Re: KX1 - very quiet on 30m and 20m
|
|
Bob,
OK, I finished the KX1 up to the point where I am able to give you some numbers. With a 50 uV input at 7040 from my XG2 signal generator, I find 0.866 volts measured across the AF Gain control (control set to maximum) with a high impedance load at the headphone jack. If I plug in headphones (Sony MDR series), the voltage drops to 0.836 volts. Of course, the AGC should be active which will keep the voltage down a bit. The KX1 has the KXB3080 option installed, and the receiver front end is a little more sensitive than either the original KX1 or with the KXB30 installed. With a 1 uV input, I read 38 to 40 mV at the same point - AGC should not be as active at that level. The voltage readings were obtained with a Fluke True RMS reading DMM. 73, Don W3FPR Don Wilhelm wrote: > Bob, > > I can't give you a measurement number right away, I do not have a > working KX1 here at the moment, but that value may be possible tomorrow > or Friday. > If you do not hear quite a loud signal with the 50 uV output from the > XG2 (or XG1 with a 20 meter crystal) - with the RF Gain at full > clockwise and the AF Gain between 25 and 35% of rotation, then there is > something wrong. > > How is the transmit power output? If that is OK, then the low pass > filter is likely OK, and you might want to look at T2. > > The KX1 audio is not super strong, and having good volume does depend on > using sensitive headphones. If your headphones do not have an > sensitivity rating greater than 108 dB/mW, then your headphones may be > the major problem, see the KX1 manual page 62. > > 73, > Don W3FPR > > Bob Jones wrote: > >> I've just completed a KX1 build with the 80/30m option and auto atu. >> >> It works on all bands but 30m and 20m require the volume control to be fully clockwise and even then it's quiet. I've carried out the recommended checks and everything appears to be fine. >> >> Having read the previous posts on 'low audio' there's an element of subjectivity regarding what this means. >> >> Does anyone know of a definitive measurement I can make to see if this radio is working as well as it should? >> >> For example, I have the XG1 and can inject a 14.060 MHz signal at 1 microvolt or 50 microvolts. With the bandwidth set to maximum, what level of signal should I expect on the input or output of the audio amplifier, or at any other point in the circuit? >> >> Any advice gratefully received. >> >> Bob, G3YIQ >> >> >> >> >> ______________________________________________________________ >> 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 >> ------------------------------------------------------------------------ >> >> >> No virus found in this incoming message. >> Checked by AVG - www.avg.com >> Version: 8.0.238 / Virus Database: 270.11.18/2009 - Release Date: 03/18/09 07:17:00 >> >> >> > ______________________________________________________________ > 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 > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.0.238 / Virus Database: 270.11.18/2009 - Release Date: 03/18/09 07:17:00 > > 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 |
|
|
In reply to this post by Don Wilhelm-4
Although it's probably not relevant to your solution, I just wanted to echo Don's comment on headphone sensitivity. I've owned a lot of electronics over the years, and the KX1 definitely wants more sensitive headphones than any of them. For instance, I have a pair of Delta Airlines earbuds that basically don't work at all, but my Bose Quietcomfort noise cancelling phones SCREAM when connected to the rig. It's a pretty low signal coming out of the jack, but with the right phones, it sounds wonderful.
|
Re: KX1 - very quiet on 30m and 20m
|
|
Ditto, Look at sensitivity ratings before you select your pair for the KX1.
I tried Shure e5's which are studio quality, had to crank the volume way down!!! 73, Bill K9YEQ K2 #35; KX1 #35; K3 #1744; mini mods -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of djmd Sent: Wednesday, March 18, 2009 7:42 PM To: [hidden email] Subject: Re: [Elecraft] KX1 - very quiet on 30m and 20m Although it's probably not relevant to your solution, I just wanted to echo Don's comment on headphone sensitivity. I've owned a lot of electronics over the years, and the KX1 definitely wants more sensitive headphones than any of them. For instance, I have a pair of Delta Airlines earbuds that basically don't work at all, but my Bose Quietcomfort noise cancelling phones SCREAM when connected to the rig. It's a pretty low signal coming out of the jack, but with the right phones, it sounds wonderful. -- View this message in context: http://n2.nabble.com/KX1---very-quiet-on-30m-and-20m-tp2499035p2500479.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ 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 |
|
|
In reply to this post by Don Wilhelm-4
Don,
thanks for that information. Here's what I have. TX appears fine. With 12.3V supply I get the following output: 80m 3.3W; 40m 2.9W, 30m 3.8W, 20m 3W. All measured by an Oakhills Labs QRP meter and a 50 Ohm dummy load. The RX seems to have a problem. I have done a careful check of all trimmer settings. Measuring across the volume control (all controls fully clockwise); XG2 set to 50 microvolts (battery checked!); Fluke 175 true RMS meter (by a lucky coincidence): 40m: 163mV with earbuds connected; 185mV without 20m: 140mV with earbuds connected; 158mV without Leaving the earbuds in, I then tried injecting the XG2 directly on the junction of L6 and the top of the RF gain pot. The difference in audio level is dramatic, particularly on 20m, but I still don't get anywhere near your figures: 40M: normal antenna input 163mV; direct to top of RF gain pot 275mV 20m: normal antenna input 140mV; direct to top of RF gain pot 550mV - getting closer! Other checks I've done: - Made sure that the break in the PCB and subsequent link is OK for the addition of the KXB3080 - Checked L6 for continuity - Checked connections to KXB3080 - and ensured that A & B are as shown in the manual i.e. B goes nearest to T1. - Checked all voltages on U6 - within spec - Checked connections of T2 and re-soldered joints (this was supplied by the Mychael) - Checked L3 is the later version with the right number of turns This feels like it may be a problem with the pin diode switches, but that still doesn't really explain why I can't get anywhere near your 0.8V figures across the audio pot. 73 Bob G3YIQ On 18 Mar 2009, at 23:39, Don Wilhelm wrote: > Bob, > > OK, I finished the KX1 up to the point where I am able to give you > some numbers. > With a 50 uV input at 7040 from my XG2 signal generator, I find > 0.866 volts measured across the AF Gain control (control set to > maximum) with a high impedance load at the headphone jack. If I > plug in headphones (Sony MDR series), the voltage drops to 0.836 > volts. > Of course, the AGC should be active which will keep the voltage down > a bit. The KX1 has the KXB3080 option installed, and the receiver > front end is a little more sensitive than either the original KX1 or > with the KXB30 installed. > > With a 1 uV input, I read 38 to 40 mV at the same point - AGC should > not be as active at that level. > > The voltage readings were obtained with a Fluke True RMS reading DMM. > > 73, > Don W3FPR > > Don Wilhelm wrote: >> Bob, >> >> I can't give you a measurement number right away, I do not have a >> working KX1 here at the moment, but that value may be possible >> tomorrow or Friday. >> If you do not hear quite a loud signal with the 50 uV output from >> the XG2 (or XG1 with a 20 meter crystal) - with the RF Gain at >> full clockwise and the AF Gain between 25 and 35% of rotation, then >> there is something wrong. >> >> How is the transmit power output? If that is OK, then the low pass >> filter is likely OK, and you might want to look at T2. >> >> The KX1 audio is not super strong, and having good volume does >> depend on using sensitive headphones. If your headphones do not >> have an sensitivity rating greater than 108 dB/mW, then your >> headphones may be the major problem, see the KX1 manual page 62. >> >> 73, >> Don W3FPR >> >> Bob Jones wrote: >> >>> I've just completed a KX1 build with the 80/30m option and auto atu. >>> >>> It works on all bands but 30m and 20m require the volume control >>> to be fully clockwise and even then it's quiet. I've carried out >>> the recommended checks and everything appears to be fine. >>> >>> Having read the previous posts on 'low audio' there's an element >>> of subjectivity regarding what this means. >>> >>> Does anyone know of a definitive measurement I can make to see if >>> this radio is working as well as it should? >>> >>> For example, I have the XG1 and can inject a 14.060 MHz signal at >>> 1 microvolt or 50 microvolts. With the bandwidth set to maximum, >>> what level of signal should I expect on the input or output of the >>> audio amplifier, or at any other point in the circuit? >>> Any advice gratefully received. >>> >>> Bob, G3YIQ >>> >>> >>> >>> ______________________________________________________________ >>> 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 >>> ------------------------------------------------------------------------ >>> >>> >>> No virus found in this incoming message. >>> Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: >>> 270.11.18/2009 - Release Date: 03/18/09 07:17:00 >>> >>> >> ______________________________________________________________ >> 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 >> ------------------------------------------------------------------------ >> >> >> No virus found in this incoming message. >> Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: >> 270.11.18/2009 - Release Date: 03/18/09 07:17:00 >> >> ______________________________________________________________ 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 |
«
Return to [KX1]
|
1 view|%1 views
| Free forum by Nabble | Edit this page |