Re: [Elecraft] K3 output buffer modification
This resistor value change has been in effect on all new K3s shipped since September of 2009. See: http://www.elecraft.com/K3/k3_app_notes.htm It will definitely improve the MDS of anything hooked to the IF port, including the P3. 73, Eric James Sarte wrote: > Terry, where did you see that the buffer mod wouldn't be necessary for the > P3? The P3 is the only reason why I performed this modification! Hopefully > someone can clarify this... > > 73 de James K2QI > > -Original Message- > From: Terry Schieler [mailto:terry.schie...@wirelessusa.com] > Sent: Thursday, January 07, 2010 11:17 AM > To: 'James Sarte'; d...@w3fpr.com > Cc: 'Elecraft' > Subject: RE: [Elecraft] K3 output buffer modification > > Did something change or am I misunderstanding Jim's post here. I thought > that the IF Output Buffer Mod would not be necessary with the P3. If one > does the IF buffer mod for the LP Pan now, how is the P3 affected in the > future? Does it then need to be reversed? > > 73, > Terry, W0FM > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Terry, where did you see that the buffer mod wouldn't be necessary for the P3? The P3 is the only reason why I performed this modification! Hopefully someone can clarify this... 73 de James K2QI -Original Message- From: Terry Schieler [mailto:terry.schie...@wirelessusa.com] Sent: Thursday, January 07, 2010 11:17 AM To: 'James Sarte'; d...@w3fpr.com Cc: 'Elecraft' Subject: RE: [Elecraft] K3 output buffer modification Did something change or am I misunderstanding Jim's post here. I thought that the IF Output Buffer Mod would not be necessary with the P3. If one does the IF buffer mod for the LP Pan now, how is the P3 affected in the future? Does it then need to be reversed? 73, Terry, W0FM __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Apparently not, because this mod is included on all new K3s Stan Rife W5EWA -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John Seney Sent: Thursday, January 07, 2010 10:22 AM To: Terry Schieler Cc: Elecraft; Subject: Re: [Elecraft] K3 output buffer modification GreAt question! 73 John WD1V Sent from my iPhone On Jan 7, 2010, at 11:16 AM, "Terry Schieler" wrote: > Did something change or am I misunderstanding Jim's post here. I > thought > that the IF Output Buffer Mod would not be necessary with the P3. > If one > does the IF buffer mod for the LP Pan now, how is the P3 affected in > the > future? Does it then need to be reversed? > > 73, > Terry, W0FM > > -Original Message- > From: James Sarte [mailto:k2qi@gmail.com] > Sent: Wednesday, January 06, 2010 5:59 PM > To: d...@w3fpr.com > Cc: 'Elecraft' > Subject: Re: [Elecraft] K3 output buffer modification > > Hi Don, > > I don't have anything that sensitive, so that's out. Perhaps I can > borrow a > spectrum analyzer from someone near me... or just wait for the P3 to > come > out. That's the only reason I performed the mod in the first place. > > BTW, thanks for the QST article info... will give that a read tonight. > > Cheers! > James K2QI > > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net 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: 9.0.725 / Virus Database: 270.14.129/2605 - Release Date: 01/07/10 01:35:00 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
GreAt question! 73 John WD1V Sent from my iPhone On Jan 7, 2010, at 11:16 AM, "Terry Schieler" wrote: > Did something change or am I misunderstanding Jim's post here. I > thought > that the IF Output Buffer Mod would not be necessary with the P3. > If one > does the IF buffer mod for the LP Pan now, how is the P3 affected in > the > future? Does it then need to be reversed? > > 73, > Terry, W0FM > > -Original Message- > From: James Sarte [mailto:k2qi@gmail.com] > Sent: Wednesday, January 06, 2010 5:59 PM > To: d...@w3fpr.com > Cc: 'Elecraft' > Subject: Re: [Elecraft] K3 output buffer modification > > Hi Don, > > I don't have anything that sensitive, so that's out. Perhaps I can > borrow a > spectrum analyzer from someone near me... or just wait for the P3 to > come > out. That's the only reason I performed the mod in the first place. > > BTW, thanks for the QST article info... will give that a read tonight. > > Cheers! > James K2QI > > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Did something change or am I misunderstanding Jim's post here. I thought that the IF Output Buffer Mod would not be necessary with the P3. If one does the IF buffer mod for the LP Pan now, how is the P3 affected in the future? Does it then need to be reversed? 73, Terry, W0FM -Original Message- From: James Sarte [mailto:k2qi@gmail.com] Sent: Wednesday, January 06, 2010 5:59 PM To: d...@w3fpr.com Cc: 'Elecraft' Subject: Re: [Elecraft] K3 output buffer modification Hi Don, I don't have anything that sensitive, so that's out. Perhaps I can borrow a spectrum analyzer from someone near me... or just wait for the P3 to come out. That's the only reason I performed the mod in the first place. BTW, thanks for the QST article info... will give that a read tonight. Cheers! James K2QI __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Hi Don, I don't have anything that sensitive, so that's out. Perhaps I can borrow a spectrum analyzer from someone near me... or just wait for the P3 to come out. That's the only reason I performed the mod in the first place. BTW, thanks for the QST article info... will give that a read tonight. Cheers! James K2QI -Original Message- From: Don Wilhelm [mailto:w3...@embarqmail.com] Sent: Wednesday, January 06, 2010 6:37 PM To: James Sarte Cc: 'Elecraft' Subject: Re: [Elecraft] K3 output buffer modification James, What do you propose to measure a 50 uV signal with? If you have equipment that will measure levels that low, then well and good, but if you are expecting to see it on an oscilloscope or RF Probe, you may as well forget it. Recall that 50 uV is an S-9 level, and is -73 dBm which is a very low level to measure. There are power measurement devices that will detect levels that low, but most of the commercial ones are priced out of the range of amateurs. One that can be homebrewed and will measure levels down to -80 dBm is the W7ZOI design using the AD8307 Logarithmic Amplifier as the front end (see Experimental Methods in RF Design, Measurements chapter or the QST article from June 2001 p38ff). To calibrate it, one must have a known level source of RF at two different levels. Those with a calibrated HP8640 signal generator (or similar) will be able to calibrate that meter with no problem. For anyone considering building such an instrument, understand that it must be well shielded. Stray coupling into the meter will produce erroneous results. Mine is in a shielded enclosure with an internal battery, and even that is not enough, the front end circuits are shielded from the rest of the assembly. Yes, it can even measure the total signal level coming in from an antenna, so it is a good performer if properly calibrated and is a very sensitive detector. With the 40 dB Power Tap, it can accurately measure power levels up to +50 dBm (100 watts), and will work up to 500 MHz with careful construction. If you want accurate power measurements, consider building one, but you need access to a calibrated power source to calibrate it - calibrate at 10 MHz, 50 MHz, 144 MHz and 450 MHz so you have a good idea of the variation with frequency - there will be some variation. 73, Don W3FPR James Sarte wrote: > Hmm... just out of curiosity, couldn't I measure the IF output using the XG2 > signal generator set to 50uV? How strong does the signal have to be? > > I'll go ahead and check the junction voltage at R9 as you suggested. > > Mni tnx! > James K2QI > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
James, What do you propose to measure a 50 uV signal with? If you have equipment that will measure levels that low, then well and good, but if you are expecting to see it on an oscilloscope or RF Probe, you may as well forget it. Recall that 50 uV is an S-9 level, and is -73 dBm which is a very low level to measure. There are power measurement devices that will detect levels that low, but most of the commercial ones are priced out of the range of amateurs. One that can be homebrewed and will measure levels down to -80 dBm is the W7ZOI design using the AD8307 Logarithmic Amplifier as the front end (see Experimental Methods in RF Design, Measurements chapter or the QST article from June 2001 p38ff). To calibrate it, one must have a known level source of RF at two different levels. Those with a calibrated HP8640 signal generator (or similar) will be able to calibrate that meter with no problem. For anyone considering building such an instrument, understand that it must be well shielded. Stray coupling into the meter will produce erroneous results. Mine is in a shielded enclosure with an internal battery, and even that is not enough, the front end circuits are shielded from the rest of the assembly. Yes, it can even measure the total signal level coming in from an antenna, so it is a good performer if properly calibrated and is a very sensitive detector. With the 40 dB Power Tap, it can accurately measure power levels up to +50 dBm (100 watts), and will work up to 500 MHz with careful construction. If you want accurate power measurements, consider building one, but you need access to a calibrated power source to calibrate it - calibrate at 10 MHz, 50 MHz, 144 MHz and 450 MHz so you have a good idea of the variation with frequency - there will be some variation. 73, Don W3FPR James Sarte wrote: > Hmm... just out of curiosity, couldn't I measure the IF output using the XG2 > signal generator set to 50uV? How strong does the signal have to be? > > I'll go ahead and check the junction voltage at R9 as you suggested. > > Mni tnx! > James K2QI > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Hmm... just out of curiosity, couldn't I measure the IF output using the XG2 signal generator set to 50uV? How strong does the signal have to be? I'll go ahead and check the junction voltage at R9 as you suggested. Mni tnx! James K2QI -Original Message- From: Alan Bloom [mailto:a...@elecraft.com] Sent: Wednesday, January 06, 2010 4:44 PM To: James Sarte Cc: Elecraft Subject: Re: [Elecraft] K3 output buffer modification Unfortunately you won't be able to measure an RF signal at the IF output connector with a meter or oscilloscope unless you have a REALLY strong signal at the K3 antenna input. As a general sanity check, you could do a DC voltage measurement on the JFET just to make sure it is still drawing current. I don't know the exact voltage, but I imagine you should get a volt or two on the JFET source (R9 source resistor). That does require taking the bottom panel off the K3 again. Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Unfortunately you won't be able to measure an RF signal at the IF output connector with a meter or oscilloscope unless you have a REALLY strong signal at the K3 antenna input. As a general sanity check, you could do a DC voltage measurement on the JFET just to make sure it is still drawing current. I don't know the exact voltage, but I imagine you should get a volt or two on the JFET source (R9 source resistor). That does require taking the bottom panel off the K3 again. Alan N1AL On Wed, 2010-01-06 at 15:33 -0500, James Sarte wrote: > Hi Alan, > > Unfortunately, I do not have a second receiver. Is there a way I can > test output voltages with my meter - anything at all to just confirm > that the resistor is indeed working? > > Anyway, the rig passed the smoke test upon turning on so that's a good > start right there. > > James K2QI > > On Wed, Jan 6, 2010 at 3:26 PM, Alan Bloom wrote: > If you have a second receiver, you could connect it to the K3 > IF output. > Tune the second receiver to 8.215 MHz and you should hear > whatever the > K3 is hearing at a similar signal level. (About an S-unit > lower with > the K3 preamp off, one S-unit higher with preamp on.) > > Alan N1AL > > > > > -- > 73 de James K2QI __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
Hi Alan, Unfortunately, I do not have a second receiver. Is there a way I can test output voltages with my meter - anything at all to just confirm that the resistor is indeed working? Anyway, the rig passed the smoke test upon turning on so that's a good start right there. James K2QI On Wed, Jan 6, 2010 at 3:26 PM, Alan Bloom wrote: > If you have a second receiver, you could connect it to the K3 IF output. > Tune the second receiver to 8.215 MHz and you should hear whatever the > K3 is hearing at a similar signal level. (About an S-unit lower with > the K3 preamp off, one S-unit higher with preamp on.) > > Alan N1AL > > -- 73 de James K2QI __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 output buffer modification
If you have a second receiver, you could connect it to the K3 IF output. Tune the second receiver to 8.215 MHz and you should hear whatever the K3 is hearing at a similar signal level. (About an S-unit lower with the K3 preamp off, one S-unit higher with preamp on.) Alan N1AL On Wed, 2010-01-06 at 14:20 -0500, James Sarte wrote: > Hello group, > > Just finished installing the K3 output buffer modification this afternoon. > I used the SMD resistor, and not the leaded part. Anyway, the most > difficult aspect was soldering the replacement back on and ensuring it > didn't move. I think I was successful. I may have chipped a tiny piece of > the black surface of the resistor off with the tip of the screwdriver used > to hold it in place during soldering. I believe its fine as I still get a > 13k ohm reading from my multimeter. I know I shouldn't test with the > resistor already soldered, but its the best I can do for now. > > Anyway, question here is how do I test to make sure that the mod was > successful? Unfortunately I do not have a spectrum analyzer. Better yet, > how to ensure that my modification didn't screw anything up? Anything I > should test for right away? > > Mni tnx es vy 73, > James K2QI > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
