+++++++++++++++++ From: "Don Brown" To: , Subject: Re: [Elecraft] K1 Receiver OPF Calibration Date: Fri, 23 May 2003 08:00:24 -0500 Hi I looked at my K1 manual and I do not see any reference to a birdie or internally generated signal on page 41. Maybe you are thinking of the external generated signal that must be applied to the input of the K1. You must supply an accurate signal then tune it for zero beat and then make the K2 display read the same. Or you can connect a frequency counter to the antenna connector. Set the RF out to a low value and terminate the at the counter end with 50 ohms. Enter tune and read the counter. Then make the K1 read the same as the counter. Your crystal calibrator should work fine with the first method above. Even better if you zero beat the calibrator with WWV using a short wave or ham receiver and then use it to calibrate the K1 Don Brown KD5NDB ----- Original Message ----- From: To: Sent: Friday, May 23, 2003 2:45 AM Subject: [Elecraft] K1 Receiver OPF Calibration > Hi everyone, didn't get a reply on this last time so here it is again. > > When doing the K1 receiver alignment, I noticed a ref to an internally > generated signal (K1 manual p41 under operating freq calibration). I think > there is a birdie off the lower band edge is this what is being referred > to, if so where does it come from, is it accurate and should I use it? I > used a xtal calibrator to do the alignment but would be interested in some > other method that was maybe more accurate. I don't have another tx or even > rx to use. > > Thanks for the help guys. BTW This reflector is a real help for beginners > like me, keep up the good work. > > Martin > M0KWV > K1 #1534 ++++++++++++++++ Date: Fri, 23 May 2003 08:53:18 -0500 To: Martin.Evans at simoncarves.com, elecraft at mailman.qth.net From: Dave Hottell Subject: Re: [Elecraft] K1 Receiver OPF Calibration Martin, While my manual p41 does not make reference to it, in the K1 there is a birdie just below the lower band edges on 7, 14, 21 Mhz. This is off the MCU oscillator. Gary made reference to it in a recent private correspondence on another matter. According to my Icom, mine resides at 6999.2, 13998.3, and 20997.6 KHz. Your's will probably be at a slightly different freq. However, this should be accurate enough for a "pretty close" calibration. Since it starts out at slightly less than 7MHz, the harmonics will slowly move away from the band edge. Mine started out 800 hz below 7 MHz then progressed to about 1600 and then 2400 below the band edge. A somewhat better method might be to pick up the W1AW broadcasts on 7047.5, 14047.5, and 21067.5. I have found these to be right-on freq. Don't know if you can rx these or not though, not sure of your QTH. You could also make arrangements with someone for a skd and have them send their exact frequency. If you set up the K1 for 150 KHz operation, you might be able to rx the WWV 10 MHz broadcast to CAL 30m. Here you will have to allow for your offset audio tone. I have my tone set at 800 Hz, so WWV comes in at 9999.2 KHz. Hope this helps. 73 de Dave ab9ca +++++++++++++++ Date: Fri, 23 May 2003 12:21:54 -0500 From: "Morrow, Michael A." To: Cc: Subject: [Elecraft] RE: K1 Receiver OPF Calibration MArtin wrote: > When doing the K1 receiver alignment, I noticed a ref to an > internally generated signal (K1 manual p41 under operating=20 > freq calibration). I think there is a birdie off the lower > band edge is this what is being referred to, if so where does > it come from, is it accurate and should I use it? Martin, It's already been pointed out that the birdie comes from the K1 front panel MCU 4 MHz crystal oscillation. I think typically K1 MCU oscillators actually oscillate (by design) at around 3999.5 kHz. Divide that by four (999.875), then multiply by the nearest "MHz" of the band edge, and you'll get a more exact value of the frequency of the band-edge birdie. Thus: Band Exact Birdie Frequency Proper K1 Zero-Beat Display (With 0.8 kHz Offset) 7 6999.1 6998.3 10 9998.8 (Requires 150 kHz 9998.0 =20 VFO option to tune=20 to it.) 14 13998.3 13997.5 18 17997.8 (Unusable. K1 won't --- tune to it.) 21 20997.4 20996.6 Most people calibrate their K1 display to show transmitter frequency, not receiver frequency. There will be an offset between those two frequencies as explained in the manual for transmitter CW offset adjustment. Typically many choose a 800 Hz offset (the transmitter will be 0.8 kHz lower than the receiver frequency). So if your receiver is zero-beat to a frequency of, say 6999.1 kHz, you'd want to calibrate the display to show 0.8 kHz below 6999.1 kHz (6998.3) in order to have the display show the *transmitter* frequency. That's what is shown in the right-most column above. It is a very thoughtful part of the K1 design that the MCU crystal=20 oscillates on purpose a little below the nominal 4.0 MHz crystal frequency. Otherwise, this band-edge birdie could always show up=20 just *inside* the ham band. 73, Mike / KK5F ++++++++++++++++++ From: "Dave" To: Subject: Re: [Elecraft] K1 Receiver OPF Calibration Date: Fri, 23 May 2003 19:09:17 +0100 Martin It doesn't matter what the "weak signal" source is, so a crystal calibrator will work fine. You will benefit from an accurate source to set each band on the correct frequency, if your crystal calibrator is on frequency then that will be OK. Here in the UK the 2.5, 5 and 10 MHz standard frequency transmissions have long since ceased. Dave, G4AON K1 #1154 +++++++++++++++++