Paul, I do not have 10 meter specific MDS measurements handy. I can measure 2 K2s sometime in th efuture if it is necessary, but it will be after I get the workbench cleared.
If you have the equipment, measure the RX VFO injection level to the mixer (TP1) - it should be +7 dBm for good mixer performance. Assuming the mixer presents a 50 ohm load to the VFO signal and your measurement does not interfere with the loading, you should see a 500 mVrms voltage at the mixer port or 1.416 volts peak to peak on a 'scope. In-situ measurement is not the best for this, substitution would be better, but you can draw some conclusions based on the in-situ measurement if the input impedance to the measuring device is high enough (you will be measuring in the 23 to 24 MHz range, so be certain the instrument is capable of accurate readings at that frequency (a 150 MHz 'scope with 150 MHz 10X probe should give good measurements). If the 10 meter VFO input is sufficient, you should be getting full benefit from the mixer, and there is nothing short of reducing the losses in the bandpass filters, T-R switch, and Low Pass Filter that will improve the MDS on 10 meters. If you find the mixer input level low, it can be adjusted by changing the resistors on the U2 buffer, but check all bands so you don't overdrive the mixer if you change the level. If the VFO level changes between bands, look for some frequency dependency in the VFO ALC circuit. My reasoning: - beyond the mixer, the K2 response should be the same from band to band, the only thing that will make changes on one band and not others is between the antenna jack and the mixer. 73, Don W3FPR > -----Original Message----- > I do own the XG2 and have performed MDS measurements on my K2 using the > XG2 and also a milspec signal generator I have. The numbers agree very > closely with published specs ON 20 METERS. On ten meters I measured an > MDS of -124 dbm (preamp off) and -130dbm (preamp on). IMHO, an MDS less > than -130 dbm is not acceptable for weak signal reception. Which means > to me that on 10 meters the preamp is absolutely required. snip... > I just want to know if my K2 is healthy > or not. > I think the K2 is a masterpiece of 'elegant simplicity' and my intent is > not to knock the rig. I've had more fun since the my kit arrived than > I've had since the heathkit days. > 73, Paul, N2PD > -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.12/628 - Release Date: 1/15/2007 11:04 AM _______________________________________________ Elecraft mailing list Post to: [email protected] 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
