Re: [Elecraft] K1: RF gain and RIT controls
Hi Bruce: 1. Has anyone come up with a good RF gain control, aka AGC threshold control? Please, no lectures about how the K1 doesn't need it, or how the RF attenuator works great. 2. In searching the archives, I found hundreds of posts about the RIT range. Too many to sort through. Is the mod in the manual the best and simplist for reducing the RIT range, or was there a definitive posting of a better one? While I'm at it, is there a drop-in replacement for the RIT control that has a center detent? You'll certainly no lectures from me, pal. However, here's some info which appears to have worked for one builder: Date: Sun, 15 May 2005 15:42:01 +1200 From: Ron ZL1TW [EMAIL PROTECTED] To: elecraft@mailman.qth.net Subject: [Elecraft] K1 revisited Hi, In a recent posting I mentioned I was not happy with the AGC action of the K1 after pulling it out of retirement for a QRP Sprint on this weekend. This is an account of what I consider, improves the set generally. I claim no originality for the ideas, and any K1 purists or designers might like to switch to the next message right now! ( Definitely YMMV) The AGC problem of giving a burst of audio when a strong signal made itself present was cured 99% by altering C31 to 1uf ( from 2.2UF) and replacing C67 with a .22uf cap ( was also 2.2uf) That sped up the AGC action and after using the set in the first 1/2 of the Sprint last evening, I was more than happy with the AGC. Howeverprobably being spoilt by the K2, I found the tuning rate a tad delicate for my fat fingers, and the RIT action was gross. OK.I know it has a large range so the set can be used in SPLIT modebut I doubt I will use that mode on the K1, so I looked in the Elecraft Reflector listings and dug out a solution posted on 20 Jul 2001 under the heading Re: K1 RIT mod, where the RIT is modified to a logrithmic action that gives a small range of tuning over about the first 25% of the controls throw, ( each side) but still retains most of the original total range. It was a tight fit getting the parts in and I had to use 1/8w resistors to obtain a decent fit, but it works fine. Now the VFO band spread. I was using the 68pf cap for C2, which gave me a 80khz tuning range. I altered C2 to 47pf and added an extra turn on L1 , and that gives me a tuning range of 51khz. A wee bit under the 55khz we are allowed here, but perfectly acceptable to me. The second half of the Sprint event is on tonight, and I am looking forward to joining in with my re-Vamped K1 . From using the set last night, there is certainly nothing wrong with the K1's receiver. I had forgotten what a fun set it is. Cheers...Ron ZL1TW 73, Tom Hammond N0SS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] K1: RF gain and RIT controls
Subject: [Elecraft] K1: RF gain and RIT controls | I'm finally going to open the box I've had for 2 years and build a K1 so I'll | have a rig for the Australian outback next month! Before I start, a couple of | questions: | | 1. Has anyone come up with a good RF gain control, aka AGC threshold control? | Please, no lectures about how the K1 doesn't need it, or how the RF | attenuator works great. | I've NEVER yet had a need for an RF gain control in the hottest most crowded contest! I VERY rarely use the attenuator in fact. | 2. In searching the archives, I found hundreds of posts about the RIT range. | Too many to sort through. Is the mod in the manual the best and simplist for | reducing the RIT range, or was there a definitive posting of a better one? | While I'm at it, is there a drop-in replacement for the RIT control that has a | center detent? PLEASE LET EVERYONE KNOW with a post if you find a pot with a center detent that will drop in the K1's front panel board! I find the RIT VERY touchy in it's present form. I would really like to limit it to 1.5-2 khz MAX each side of center, plus have a reliable notch to come back to for a center reference. T'would be very nice. Still in spite of this, best QRP rig I've ever had! 73, Sandy W5TVW | Thanks! | -Bruce AA5B | ___ | Elecraft mailing list | Post to: Elecraft@mailman.qth.net | 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 | | | | -- | No virus found in this incoming message. | Checked by AVG Anti-Virus. | Version: 7.0.323 / Virus Database: 267.8.7/34 - Release Date: 6/29/2005 | | ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] K1: RF gain and RIT controls
I like the 150 kHz range on 30m for having WWV and on 20m (and 15m to some extent) for big DX contests. While the tuning may be somewhat sensitive, it is not difficult to control with a gentle touch. If you tend to stick close to the QRP frequencies (or the core areas of each band) and don't need WWV, 80 kHz is the way to go. Scott N1AIA ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K1: RF gain and RIT controls
I soldered a 10K resistor across the RIT pot and magically cut the range in half. It was easier than dealing with C7 on the rf board. I find RIT=Off a satisfactory center detent. Per your request, I'll spare you my comments on the gain control as the K1 doesn't need one. Eric KE6US -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, June 29, 2005 7:51 PM To: Elecraft@mailman.qth.net Subject: [Elecraft] K1: RF gain and RIT controls I'm finally going to open the box I've had for 2 years and build a K1 so I'll have a rig for the Australian outback next month! Before I start, a couple of questions: 1. Has anyone come up with a good RF gain control, aka AGC threshold control? Please, no lectures about how the K1 doesn't need it, or how the RF attenuator works great. 2. In searching the archives, I found hundreds of posts about the RIT range. Too many to sort through. Is the mod in the manual the best and simplist for reducing the RIT range, or was there a definitive posting of a better one? While I'm at it, is there a drop-in replacement for the RIT control that has a center detent? Thanks! -Bruce AA5B ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
