++++++++++++++++++ From: "Don Brown" To: "Bill Coleman" , "Elecraft" Subject: Re: [Elecraft] K2: S meter CAL S HI & oddity Date: Thu, 21 Mar 2002 09:29:18 -0600 Hi You want the point where the meter switches form 10 to 9. I find a low of= about 196 and a hi of about 20 will give a reading closer to 50 uV =3D S= 9. I set the radios I have built by connecting a signal generator and ste= p attenuator set for 50 uV then adjust for S9 on the meter. I arrived at = the above settings by this method on 4 K2's I have built. It really matte= rs not, you can set the meter however you prefer. The manual setting is j= ust a starting point. Don Brown =20 KD5NDB ----- Original Message ----- From: Bill Coleman Sent: Thursday, March 21, 2002 9:05 AM To: elecraft at mailman.qth.net Subject: [Elecraft] K2: S meter CAL S HI & oddity CAL S LO went as specified. CAL S HI, however, I was unable to extinguish the right-most LED. Even if I ran the calibration all the way down to 001, LED 10 was still lit. If I backed the calibration off to a reasonable value (the manual says about 25), that was about the point where it jumped from LED 9 to LED 10. Is this a documentation problem? Are you supposed to be able to extinguish the rightmost LED? In tuning around last night on 40m with an antenna, I also noticed the S meter is real stingy. I couldn't tune anything stronger than about LED 4 or 5. Any ideas? +++++++++++++++++++ Subject: Re: [Elecraft] Drum Roll Please Date: Mon, 1 Apr 2002 11:44:50 -0500 To: "John McClain" , "K2" From: Bill Coleman On 3/30/02 4:01 PM, John McClain at digi2 at earthlink.net wrote: >Everything went together fine >except I think I did a pretty bad job aligning the filters and, like a >lot of others, the S-Meter is very stingy. My S-meter problem was solved by replacing the D1 on the control board with one with a .630 Vf (the one that came out was .595 Vf). I also had a bad Q12 on the control board. Replaced it with a 2N2222 (I don't have any PN2222As). Works great now. 40m SWBC stations are 20-30 over S9, right where they should be. Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ++++++++++++++++ From: Marteinn Sverrisson Date: Mon, 16 Dec 2002 09:51:22 +0000 To: elecraft at mailman.qth.net Subject: [Elecraft] S-meter activation, a simple cure S-meter/AGC activation from strong out of band stations has long been a problem for me when I use the OP1 filter. Now I have hopefully solved the problem with the S-meter/AGC activation. The solution is to "clean up the AGC IF signal" by inserting a simple 153kHz bandpass filter between the AGC IF amplifier U2B and the AGC rectifier D1. The filter does not interfere with normal AGC action as far as I can tell. I do not hear any plopping on SSB or CW with the filter in. The official Elecraft solution to the problem is to make the 20m/30m/17m etc BP filters narrower and should of course be done first. THE FILTER Here is a ASCII schema of the filter, it is very simple and does not need trimming, it uses 4 standard value components a 2.2k resistor to control the Q of the filter and 10nF DC blocking cap and a resonator which uses standard values of 3.3nF and 330uH, it is inserted between pin 7 of the AGC IF amplifier U2B and R3 the 10k resistor. pin7 on U2B ---2.2k---------R3------ D1------- | | 10nF | | ------- | | 3.3nF 330uH | | ------- | Ground 3.3nF and 330uH are 5% tolerance. The -3dB BW is approx 20kHz, -20dB at 100kHz and 350kHz. Insertion loss about 1dB. How I installed the filter: Just remove the top (if you have KPA100 remove the small top plate) of the K2, then you have access to the Control board, no boards have to be removed. I unsolder-ed one end of the R3 10k resistor, which is located near the top left on the Control board (viewing the component side) and inserted the 2.2k in the hole and connected the two together, the resonator circuit is then connected via the 10nF DC blocking cap. No traces to cut!! You should readjust the AGC threshold - R1 on the control board - to compensate for the insertion loss of the filter. (tnx Sverre LA3ZA) Details on: http://www.raunvis.hi.is/~matti/TF3MA/agc.html BTW if you have a AM LW radio try listen to the AGC IF signal on 153kHz, just hold the radio close to the left upper side of K2, makes it simple to listen to AM!! 73 Matti, TF3MA +++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Marteinn Sverrisson'" , Subject: RE: [Elecraft] S-meter activation, a simple cure Date: Thu, 26 Dec 2002 16:49:02 +0100 I have installed Marteinn's simple AGC IF filter. It really decreases the S-meter activity from signals that you cannot hear in the passband, so I am very happy with it. Now I have made the OP1-filter (SSB filter) to be FL1 in my CW setup again, as I had removed it due to the S-meter activation problem previously. The filter will reduce gain in the AGC loop slightly, meaning that the overall gain of the K2 will increase. This can be compensated by adjusting R1 on the control board so that pin 5 on U2 reads about 4.1 Volts (Elecraft's serial # 3000+ recommended value is 3.90 Volts). If you already have a K2 where the gain reduces a little too much on a quiet band when the AGC is turned off, insertion of this filter will alleviate this problem. 73 and Merry Christmas Sverre LA3ZA www.qsl.net/la3za ++++++++++++++++++ From: "Dave" To: Subject: Re: [Elecraft] no s meter Date: Thu, 8 May 2003 21:15:01 +0100 John Have you accidentally turned the AGC off? Pre/ATT and AGC keys together. Dave, G4AON ----- Original Message ----- From: "n3drk" To: "elecraft" Sent: Thursday, May 08, 2003 9:05 PM Subject: [Elecraft] no s meter > Dont know what i did but now my s meter doesnt work. I wanted to tweak the s > meter and followed the instructions as per the manual. But now the s meter > doesnt work. The menu shows the graph in the dot position so it is not off. > The rf/alc portion of the meter works. I tried to reset the meter but now i > dont have any s meter indications. > > Anyone know what i may try next. Dont really need the s meter but i like to > keep everything in operation. > > thanks in advance > > john +++++++++++++++++