+++++++++++++++++++++++++++++++++++++++++++ Date: Tue, 20 Mar 2001 19:59:32 -0500 From: "Mark J. Yergin" Subject: [Elecraft] 80 or 150 kHz for the K1? I'm looking for opinions as to which is the better set up for the K1 with the 40 and 20 meter bands - 80 or 150kHz? I think 150 kHz would allow for coverage of the entire CW portions of each band. Which have K1 builders selected and why? Mark J. Yergin, N8IFU Novi, Michigan ++++++++++++++++++++++++++++++++++++++++++ Date: Wed, 21 Mar 2001 03:02:26 +0000 From: borrello at att.net Subject: Re: [Elecraft] 80 or 150 kHz for the K1? If you want to be able to work the Novice portion of 40 meters, you will need to set it for 150 kHz. This portion of the band has the advantage of only allowing 200 watts, so, as with the 30 meter band, you will not be battling the kW guys. However, most of the hot DX stations will not be in this portion of the band. I chose the 80 kHz option because in addition to the 20/40 meter board, I have a 30/17 meter board, and the extra bandwidth would be wasted. Also, I am mostly interested in the lower portions of 40M and 20M anyway, plus I have another QRP rig which covers the higher end of the 40M CW band. The K1 tunes very nicely with the 80 kHz bandwidth, but I don't know what the tuning is like with 150. Hope this helps, Joe Borrello, W8UH +++++++++++++++++++++++++++++++++++++++++ Date: Tue, 20 Mar 2001 19:18:47 -0800 From: alta Subject: Re: [Elecraft] 80 or 150 kHz for the K1? Mark ... I found that the VFO knob was too coarse at 150 kHz (180 actual). At 80 KHz, the knob had reasonable resolution, but I wnated to also cover the QRP frequency (110) in the 40m novice band. Here's what I finally settled on: The VFO knob is nonlinear, making it overly coarse in my favorite spots at the low end. So, I linearized the VFO control by adding a 68K resistor between the wiper and hot side of the VFO pot. Then, I added 20 pf (temp compensated caps) to the Elecraft-supplied 68 pf cap. This gave me 6999-7120 kHz of reasonably-linear VFO control. Reed ... K7FLY +++++++++++++++++++++++++++++++++++++++++ Date: Sun, 25 Mar 2001 23:52:12 -0500 From: Richard Arland Subject: [Elecraft] K1 AGC Cap Change Last evening I did the "C31 cap change mod" to s/n 0017. I replaced the 2.2 uf with a .47 uf and the difference was amazing. The AGC is much more responsive with the new cap in place. I also experimented with C2: Originally I installed a 100 pf SM. Got lots of tuning range but the rate was extremely fast. Then I settled on a 68 pf SM but, after about 3 months of use, I changed it out for a 50 pf SM. With the 50 pf I get 62 khz of tuning range. It covers from 14.001 to 14.063 and 7.007 to 7.069 khz on 20 and 40 respectively. I don't mind losing the bottom of 40 meters and the tuning is MUCH improved. I may go back and tack a 5 pf SM in parallel with the 50 pf and see if I can get full band coverage on 40, but that is not an urgent priority. 74 Rich K7SZ +++++++++++++++++++++++++++++++++++++++++++++++++ Date: Mon, 26 Mar 2001 00:30:35 -0700 From: "Rod Cerkoney" Subject: Re: [Elecraft] K1 AGC Cap Change Richard, >From: Richard Arland >Reply-To: Richard Arland >To: elecraft >Subject: [Elecraft] K1 AGC Cap Change >Date: Sun, 25 Mar 2001 23:52:12 -0500 > >I get 62 khz of tuning range. It covers from >14.001 to 14.063 and 7.007 to 7.069 khz on 20 and 40 respectively. I >don't mind losing the bottom of 40 meters and the tuning is MUCH >improved. I may go back and tack a 5 pf SM in parallel with the 50 pf >and see if I can get full band coverage on 40, but that is not an urgent >priority. Rather than change the cap compress/spread as necessary the windings on the VFO toroid, L1, to raise the VFO maximum frequency, which will result in covering the low end of each band. Mathmatically: Fpmo - Fvfo-max - Fif = F low of band where Fvfo-max = max. VFO Freq Fpmo = Freq of Pre-mix Osc. (supplied XTAL) Fif = 4915 (IF frequency) Example for 20m Let Fvfo-max = 3075 and Fpmo = 22000 (the PMO Xtal) 22000 - 3075 - 4915 = 14010 but if Fvfo-max = 3085 22000 - 3085 - 4915 = 14000 73, Rod N0RC Fort Collins, CO ++++++++++++++++++++++++++++++++++++++++++++++++++++++ From: "Morrow, Michael A." To: "'elecraft at mailman.qth.net'" Date: Tue, 26 Nov 2002 12:44:56 -0500 Subject: [Elecraft] Re: K1 1408 is underway...80 vs 170 kHz VFO span Jess wrote: Can anyone comment on the plus or minus attributes of 80khz vs 150 khz of band coverage? It would seem that the only reason to select 150 would be for WWV reception on 30 meters or to listen to the novice portion of 40? Jess --------------- I've used the 170 kHz (which is actually what you'll get) option for two years on K1 #175. I wouldn't have it any other way. Tuning rate is still good (about 17 kHz/turn) and is remarkably linear IF you have a 100 kohm resistor connected from the hot side to the wiper on the VFO potentiometer. I believe the later models of the K1 come with this resistor as standard. The advantages of 170 kHz span are: (1) Full coverage of the 40m CW band, PLUS some overlap into the first 20 kHz of the phone band, just in case you needed to try a cross-mode contact (The K1 receives in LSB mode). (2) Almost full coverage of the 15m CW band (had you chosen that over 17m).. (3) 10 MHz WWV coverage, as you mention. Reason (1) alone is enough for me. There's a lot of activity there (and also a fair amount in the Novice portion of 15m when a contest is raging). 73, Mike / KK5F +++++++++++++++++++ From: "Wallace, Andy" To: "'Elecraft'" Date: Mon, 9 Dec 2002 08:08:44 -0500 Subject: [Elecraft] noodling with K1 VFO range In the CQWW contest, I was hearing interesting DX at the limits of my K1 80 kHz VFO range. This past weekend, I decided to see how I liked the extended 150 kHz range by putting a bigger cap at C2 (68pF = 80 kHz, 120 pF = 150 kHz). I pulled the stock cap and saved it. I then installed a 68pF surface mount cap on the back of the board with a jumper wire to connect the other lead to the hole for C2. On the top of the board, I stuck a two-position jumper in one hole for C2, and ran a wire toward the other hole. Then, I experimented with cap values to use between the wire and the other C2 hole. It sounds confusing the way I am writing it but basically I have two caps in parallel (which adds), one on each side of the PC board. With a jumper installed, I get the pair paralleled. Without the jumper, I get just the bottom 68pF cap and the stock ~80 kHz range. I settled on a 47pF cap for the top side jumper. This gives enough overlap that I can calibrate things and still have about 150 kHz range. Now, remember if you change caps, you'll have to redo the VFO range (adjusting toroid spacing) to have the counter-clockwise end meet 3.100 MHz; redo the band OPF calibrations, and redo the OFS offset adjust. Your RIT range will change, also. My idea of using the jumper means that I will have to redo all these if I decide to change back to 80 kHz -- still, easier than getting the soldering iron and solder sucker out during a contest. NOTE: it's not necessary to change the 30m crystal if you had previously installed the one for 80 kHz range starting at 10.100 MHz. The only loss here will be that you'll be tuning 10.100 - 10.250, and won't get WWV at 10.0 MHz. How do I like it? Well, the jury is still out. I'm getting about 16 kHz per revolution on the VFO, which is not too bad. However, it is tougher to zero beat the other stations (but still possible). There are also some nonlinearity "jumps" at one end of the VFO but it may be because I have worn my pot down after months of steady band cruising. ;-) The activity up to the ~150 kHz range of the bands has not been overwhelming. I did hear an HK station on 21.135 the other night, and I still need Colombia, so I guess I'll leave it in for now. If I decide I like it overall, I'll pull my jumper setup out and just install the stock factory 120 pF polystyrene cap. Obviously the K1 was designed with this in mind and it IS perfectly usable, but the 80 kHz range makes things even smoother. -Andy +++++++++++++++ From: "Wallace, Andy" To: "'Elecraft'" Date: Mon, 30 Dec 2002 07:50:13 -0500 Subject: [Elecraft] maximizing useful K1 VFO range Well, I had my K1 doing 150 kHz VFO range for a while, but changed it back to 80 kHz with the stock 68pF VFO cap again. The wider range is nice to scan more of the band but I was hearing very little activity above the 100 kHz mark on the bands. I hope CW isn't dying out faster than before! Anyway, here is a tip which many of you might benefit from. After doing your CAL OSC and CAL OPF operations to make the VFO tune the proper range, set the bands on frequency, then reajust the VFO toroid spacing to compensate for the variations in the two or four bands installed in your K1. Take note of the lower band-edge-tuning of each band with the VFO fully counter-clockwise. Whichever one starts the highest -- closest to the lower ham band edge -- is what you want to adjust. With the VFO nylon hardware tightened down, take the insulated tweaker or some other tool and squeeze or separate the last VFO turn from the rest. Even with the hardware tight you can have a slight movement -- and that is all that should be necessary. After the rig has warmed up, try to make the fully CCW VFO position be as close to that band edge as possible. With my rig, it was the 40m band. Now after doing this adjustment, the other bands also have the maximum operating range available: 6.998 - 7.091 10.092 - 10.185 13.992 - 14.085 20.990 - 21.083 See how the lower edge of 40m is what limited the range of the others? And my final VFO CAL OSC comes out to 3.091 - 2.998. --Andy ++++++++++++++++++ From: "Don Brown" To: "SP5DDJ" , "Wallace, Andy" , "'Elecraft'" Subject: Re: [Elecraft] maximizing useful K1 VFO range Date: Mon, 30 Dec 2002 17:11:29 -0600 Hi You can split the difference and use a 100 pf NPO cap for C2 and get ~100 kHz. Try it. Don Brown KD5NDB ++++++++++++++++ From: "Morrow, Michael A." To: "'SP5DDJ'" , "Wallace, Andy" , "'Elecraft'" Subject: RE: [Elecraft] maximizing useful K1 VFO range Date: Mon, 30 Dec 2002 18:36:58 -0500 > From SP5DDJ: > > I do regret that I made a choice of 80 kHz instead of 150 > kHz, especially on 15m band. I find that the only disadvantages to the 170 kHz range are precise dial adjustment and keeping the dial exactly on frequency when letting go of the dial. All such problems vanished after I put a piece of felt between the panel and the VFO knob. The resulting slight resistance to rotation was a great improvement. I find the activity in the old 40m novice band alone to be well worth using the 170 kHz option on the K1. 73, Mike / KK5F ++++++++++++++++ From: "Don Brown" To: "Sandy W5TVW" , "Morrow, Michael A." , "'SP5DDJ'" , "Wallace, Andy" , "'Elecraft'" Subject: Re: [Elecraft] maximizing useful K1 VFO range Date: Tue, 31 Dec 2002 06:53:18 -0600 Hi One of the felt disks used on a Dremal tool for polishing jewelry works and is the right size. You will need to make a hole in the center and may need to split in two to reduce the thickness. I have also tried the large felt pads used on the bottom of furniture feet. They will work also and have adhesive backs. All of this experimenting with felt pads I did a couple of years ago then I changed to the metal shaft pot and now I don't need the felt pads. I like the feel of the metal shaft pot much better, Mouser has them for about $14 P/N 652-3540S-1-104 Rather than using the plastic spacer I used a nut on both sides of the pot with the locknut on the back this moves the knob closer to the front panel. Some have suggested cutting the shaft down, but I have found this is a better solution Don Brown KD5NDB ++++++++++++++++