++++++++++++++++++ From: "Chuck Roedel" To: "elecraft L-serve" Subject: Fw: [Elecraft] K1 frequency range ?? Date: Thu, 10 Jan 2002 18:58:54 -0500 ----- Original Message ----- From: Chuck Roedel To: elecraft L-serve Sent: Thursday, January 10, 2002 2:20 PM Subject: [Elecraft] K1 frequency range ?? Hi everyone, K1-4 #992 is up and running! I do have one question. I have carefully aligned it and found that the frequency range is from approximately 6.090mHz - 7.079 (other bands same 10kHz below band edge). Is there a way to raise the frequency spread to 7.000 - 7.090 ?? Any ideas or fixes will be appreciated. Chuck, WA2MXR ++++++++++++++++++++ From: DolfinDon at aol.com Date: Thu, 10 Jan 2002 21:07:53 EST Subject: Re: Fw: [Elecraft] K1 frequency range ?? To: elecraft at mailman.qth.net In a message dated 1/10/2002 7:56:30 PM Central Standard Time, DolfinDon at aol.com writes: Just spread out the turns of L1. Oops I screwed up. Spreading the turns on L1 will raise the vfo frequency but you want to rase the receiver frequency. To do that you must lower the vfo frequency so you must compress the turns on L1 to do that. sorry for the confusion Don Brown +++++++++++++++++++++ From: "Chuck Roedel" To: "elecraft L-serve" Subject: Fw: Fw: [Elecraft] K1 frequency range ?? THANK YOU !! Date: Fri, 11 Jan 2002 13:35:05 -0500 Many Thanks to everyone who helped to "adjust" K1 #992. "SQUEEZED" the coil and "WALLAH" It now has a band spread of x000.0 to x090.4. I and the K1-4 are happy !! I'm back on the air after a 22 year layoff. The K1-4 was a treat to assemble. I only fouled up twice - a misplaced choke and a wire on the toroid transformer in the wrong hole. The trouble shooting section lead me to the problem(s) in a flash and after a minute with the "solder sucker" and a few unkind words to myself about my stupidity (or was it my "over 50" eyesight?) the K1 came to life. I sounded like Colin Clive yelling, "It's ALIVE !!!" I have added the ATU and the NB without a hitch. Now to treat myself to a decent paddle. Chuck, WA2MXR "Waaa-Two-Mixer" K1-4 #992 ++++++++++++++++++++++ Date: Fri, 11 Jan 2002 13:14:06 -0600 From: Mike To: Chuck Roedel CC: elecraft L-serve Subject: Re: Fw: [Elecraft] K1 frequency range ?? Chuck Roedel wrote: > K1-4 #992 is up and running! > frequency range is from approximately 6.090mHz - 7.079 (other bands > same 10kHz below band edge). You are lucky if all the other bands also start the same 10 kHz below band edges. That means all your KFL1-4 crystals are oscillating at the same amount of departure from the nominal value for each band. As has been pointed out in the postings of others, slightly compressing the turns of L1 (to LOWER the subtractive VFO) on the RF board will RAISE the operating frequecy for ALL four bands by the same amount. If you really want to ensure sufficient frequency coverage, you could increase the value of VFO capacitor C2 from the 68 pF supplied. I used the supplied 120 pF capacitor and got a 170 kHz tuning range, which I like VERY VERY much! I have found, IMO, there to be NO disadvantage associated with the wider tuning range, and it is particularly valuable on the K1-4, since it allows complete coverage of the 40m CW band and almost all of the 15m CW band (not all interesting QSOs take place on the low ends). I did, however, linearize the VFO tuning rate greatly by the simple addition of a 100 K ohm resistor from the hot side to the wiper of the VFO pot, and I installed some soft felt washers behind the VFO knob and the panel to put a little drag on the tuning. I'd have done both of those additions even if I had used the 80 kHz range option. Others have chosen values of C2 between 68 and 120 pf to get intermediate tuning ranges. You'd need to chose any capacitor characteristics carefully to minimize temperature vs. capacitance effects on VFO stability. Mike / KK5F ++++++++++++++++++++ Date: Fri, 11 Jan 2002 14:24:53 -0600 From: Mike To: Chuck Roedel CC: elecraft L-serve Subject: Re: Fw: Fw: [Elecraft] K1 frequency range ?? THANK YOU !! Chuck Roedel wrote: > Many Thanks to everyone who helped to "adjust" K1 #992. > "SQUEEZED" the coil and "WALLAH" It now has a band spread of > x000.0 to x090.4. You will find, due largely to changes in ambient temperature, that the range you see now will not always remain with the low end at xxx00.0 kHz. Don't be surprised if sometimes when you turn it on the low end starts at xxx00.9 or so, or at xxx99.5 or so. Because of that effect, I set L1 so that my most limiting band low end begins at xxx99.0 kHz or a little lower in order that I always have full coverage down to the low end of the ham band. Mike / KK5F ++++++++++++++++++++++