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:[email protected] >> >> 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
