+++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Mon, 30 Oct 2000 11:02:29 -0700 From: Wayne Burdick Subject: [Elecraft] K1 Transmit offset adjustment -- new method A few K1 builders have had trouble hearing the transmit monitor tone using the method described in the manual. If this applies to you, please try the following method: 1. Take the top cover of the K1 off, leaving the bottom cover on. 2. Connect a dummy load. 3. Use the menu to set up the following: OUT = 2.0 W; AGC = OFF; STL = 0 (no sidetone). 4. Connect a key and transmit a few characters. You should hear no sidetone at all. 5. Using a 1 to 2" jumper wire, short the two "OFS" pads together from the *top* side (the two pads are located near Q10 and R2). Tap the key again: you should now hear the transmit monitor tone. 6. Use the menu to increase the sidetone volume until you can hear it along with the TX monitor tone as you key the transmitter. Then adjust C13 so that the transmit monitor tone is close in pitch to the sidetone. Let me know if this helps. 73, Wayne Bob Hightower wrote: > > At 07:02 PM 10/29/2000 -0700, you wrote: > >Hi Bob, > > > >Thanks for your K1 comments. > > > >As for your TX offset adjustment: You have to short together the "OFS" > >pads, AND make sure that AGC is turned OFF, AND have a dummy load > >connected, AND set the sidetone so that it isn't overwhelming the TX > >monitor tone. You may have to turn the sidetone volume up or down -- > >give it another try. > > > > Tried all that again, and still have no transmit monitor tone, unless it is > so faint it's not audible. > > Bob Hightower NK7M > Chandler, AZ > SOC #20 > K2 #157/255 ++++++++++++++++++++++++++++++++++++++++++++++ Date: Fri, 19 Jan 2001 09:15:54 -0600 From: Ken Paulson Subject: [Elecraft] RE:Help! K1 Transmit Offset Adjustment failed Hello Axel, I had a very similar problem with my K1 #166. I found that if I went back and adjusted the trimmer capacitor for the RX BFO, I could find more than one position where is lined up properly. At one of these other positions, I was then able to get the TX offset adjustment to work. It may have been that the RX was set to one side band of the carrier, and the TX to the other, so that the TX signal is outside of the RX passband. Anyway, after a tweek on the RX BFO, I was able to get the TX adjustment to work as expected. Let us all know what you discover. Good Luck, and enjoy your K1! Ken N0HRL =====original message========== Date: Thu, 18 Jan 2001 08:48:34 +0100 From: "Axel Schaeffler" Subject: [Elecraft] Help! K1 Transmit Offset Adjustment failed Hi Elecrafters, yesterday I finished my K1 #169 and it passed all tests with flying colors, except the very last one! - ---snip--- But I am not able to perform the Transmit Offset Adjustment described on page 47 of the manual! - ---snip--- vy 72, Axel DF2UZ ++++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sun, 4 Mar 2001 16:08:36 +0100 From: "Dieter Klaschka" Subject: Re: [Elecraft] K1 Band 2 not working HELP? - ----- Original Message ----- From: "Tom Mihelich" To: Sent: Saturday, March 03, 2001 10:40 PM Subject: [Elecraft] K1 Band 2 not working HELP? > Hi All, > > I seem to have run into a problem in getting my band 2 (20M) to > recieve anything during the band pass filter alignment. I just > recieve background hiss across the whole band while I try to adjust Hi, Tom , I had a similar problem with 378. Even if I can't get the reasons of your problem mine were very simple indeed. The filters are "very sharp" i.e. (and I did understand that only when I got a hint on that!). Try to adjust again from the rx side, finding a quiet sig and tune it to peak, than try to adjust the tx. I was told " then from nowhere you will see the external wattmeter showing a sig" - and excactly that happened ( I am sorry for some poor explanations possibly, mothertongue is DL language, hi) Good luck, Dieter.dl2bqd ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Wed, 18 Apr 2001 17:43:04 -0400 From: "Morrow, Michael A." Subject: RE: [Elecraft] K1 Transmit Offset Adjustment Ken, Here is an example of what's taking place when you do the K1 offset adjustment: My sidetone set by STP is 600 Hz. This is an "artificial" sidetone generated by the main processor unit (MPU), and is NORMALLY the only tone heard on transmit. Simply changing STP has NO effect on the offset between transmit and receive frequencies...that would take a digital frequency control system like the K2 uses. The offset between the receive frequency and the transmitted frequency in the K1 is controlled by adjusting C13 in the transmit mixer stage (U8). The receiver in the K1 receives LSB mode, so if I tune the receiver to 7010 kHz, a signal at 7009.4 kHz would produce a 600 Hz tone in the K1 receiver. Thus when I adjust offset with C13, I desire to offset the transmitter frequency to be 600 Hz below the receive frequency. I can tell when this happens by listening to the K1's transmitter signal in the K1 receiver and comparing the tone generated to the sidetone from the MPU. But, the only way I can hear the K1's transmitted signal in the K1's receiver is to reduce some of the muting in the receiver audio. This is done by disabling one of the muting switches, Q10, with the jumper at OFS. Then I can hear both the MPU sidetone and the receiver tone, and match them using C13 to change the transmit frequency to change the tone from the receiver. Voila! I've now got my transmitter offset adjusted to be the same as sidetone pitch I set with STP. If I decide later I want a different sidetone, say 800 Hz, and I set that with STP, this will NOT change the actual offset. I'll have to go back and do the transmit offset adjustment to put the transmitter 800 Hz below the receiver. 73, Mike / KK5F > ---------- > From: Ken Ludwick[SMTP:ludwick at aps.edu] > Sent: Wednesday, April 18, 2001 1:21 PM > To: elecraft at qth.net > Subject: [Elecraft] K1 Transmit Offset Adjustment > > A lot of us have had problems with the Transmit Offset Adjustment. One > thing > that bothers me is that I don't know what is happening when I do this. We > set the "Offset" by blending two signals together. This seems to be > contradictory. Am I trying to set the radio where I transmit on one > frequency and receive on another like in VHF? Or am I trying to adjust the > transmit and receive frequencies to be Identical. Probably a very basic > question, but would have liked to have seen a brief explanation of the > process in the manual. > > Tnx de Ken ++++++++++++++++++++++++++++ Date: Tue, 24 Jul 2001 13:12:24 -0500 From: Mike Subject: Re: [Elecraft] Newbie Question on using Spot feature (Long Reply) Victor Trucco wrote: > What is the recommended hz I should set the sidetone pitch to be able > to properly tune a cw signal? ... Does different pitch settings affect > whether your able to zero beat a signal? Victor, Most CW operators like a sidetone between 600 to 800 Hz. Sidetone is the pitch you hear in the receiver when YOU are transmitting. But your question really pertains more to the adjustment of the OFFSET of the K1 transmitter frequency from the K1 receiver frequency, which is a completely separate adjustment. In the K1, sidetone is "artificially" generated by the front panel MPU, and can be set to whatever you want. On many *other* radio designs, the sidetone is generated by the partially muted receiver detecting the actual transmitted signal. This latter design has the advantage that whenever the transmitter frequency offset from the receiver frequency is adjusted, the effects will be heard in the receiver. But, this is NOT the system used in the K1. The artificially generated sidetone adjustment of the K1, made from the front panel menu, has absolutely NO effect of the actual offset between the receiver frequency and the transmitter frequency. For the STP adjustment to have been able to change the transmitter offset, a digitally-controlled frequency generation system such as found in the K2 would have been required. The offset between transmitter and receiver frequency is adjusted by C13 on the RF board. In ANY CW transceiver, the sidetone frequency should be the SAME as the offset between the transmitter and the receiver frequencies. For the K1, this is a two step process: (1) Set the pitch of the artificial sidetone using STP to that which is pleasing to you. (2) Adjust the transmitter offset using C13 to make the transmitted frequency offset below the receiver frequency the same as your sidetone frequency. This is described on page 47 of the manual, revision D. What follows is an example of what's taking place when you do the K1 offset adjustment, using some numbers from my K1: I used STP to set my sidetone to 600 Hz. This artificial sidetone is NORMALLY the only tone heard on transmit. The offset between the receive frequency and the transmitted frequency in the K1 is controlled by adjusting C13 in the transmit mixer stage (U8). The receiver in the K1 receives in LSB mode. You can verify the mode in which any receiver is operating simply by tuning in a signal. If the pitch of the signal gets higher as you tune higher in frequency, then the receiver is in LSB mode. If the pitch gets lower as you tune higher, it is in USB mode. If I tune the K1 receiver to 7010.0 kHz, receiving a signal at 7009.4 kHz would produce a 600 Hz tone in the audio. When I adjust offset with C13, the goal is to offset the transmitter frequency to be 600 Hz (same as my sidetone) below the receive frequency. I can tell when this happens by listening to the K1's transmitter signal in the K1 receiver and comparing the tone generated to the sidetone from the MPU. BUT, the K1 receiver is *normally* so well muted on transmit that only way I can hear the K1's transmitted signal in the K1's receiver is to reduce some of the muting in the receiver audio. This is done by disabling one of the muting switches, Q10, with the jumper at OFS. At that point I can hear both the MPU sidetone and the receiver output tone when transmitting. Adjusting C13 to alter the transmit frequency will change the tone heard from the receiver, while the MPU-generated sidetone pitch remains constant. When I hear both tones are the same pitch, I've now got my transmitter offset adjusted to be the same as the sidetone pitch I had set with STP. If I don't properly adjust the offset of the transmitter frequency from the receiver frequency, then something bad can happen. EXAMPLE: I tune in a CW signal and get a desired pitch of the other station of about 600 Hz. My K1 receiver is now, say, on 7010.0 kHz and operates in LSB mode, so that means the other station must be transmitting about 600 Hz BELOW 7010.0 kHz, or 7009.4 kHz, to produce the 600 Hz tone in my audio. When I transmit back to him, because I had adjusted my transmitter offset to be 600 Hz below the receiver, I too will be transmitting on 7009.4 kHz. Suppose that the other station's receiver operates on USB mode and has a sidetone/transmitter offset of 800 Hz. Operating in USB mode for a 800 Hz offset means that the other station's receiver frequency will be be 800 Hz BELOW his transmitter frequency. Thus, HIS receiver frequency will be 7009.4 kHz (HIS transmitter freq) - 0.8 kHz (HIS offset) = 7008.6 kHz. Situation A (GOOD): I properly set MY offset such that I transmit 600 Hz below my receiver frequency. I'll be transmitting on 7010.0 kHz (MY receiver freq) - 0.6 kHz (MY offset) = 7009.4 kHz. The other station's receiver is tuned to 7008.6 kHz, so my signal on 7009.4 kHz will produce a tone of 7009.4 kHz - 7008.6 kHz = 0.8 kHz (800 hz) in his receiver audio. The other station will hear my signal at HIS desired 800 Hz pitch, even though his receiver operates on the opposite sideband as mine. Situation B (BAD): I IMproperly set MY offset such that I transmit 1500 Hz below my receiver frequency instead of 600 Hz. I'll be transmitting on 7010.0 kHz (my receiver freq) - 1.5 kHz (my offset) = 7008.5 kHz. The other station's receiver is tuned to 7008.6 kHz, so my signal on 7008.5 kHz will be heard in his receiver ONLY if his receiver were on LSB mode instead of USB (or had poor opposite sideband rejection), and would produce a tone of 7008.6 kHz - 7008.5 kHz = 0.1 kHz (100 hz). Because of this, the other station won't even my 100 Hz pitch, opposite sideband signal when I call. Situation C (BAD): Let's say I IMproperly set MY offset such that I transmit 0 Hz below my receiver frequency instead of 600 Hz (no offset at all). I'll be transmitting on 7010.0 kHz (my receiver freq) - 0.0 kHz (my offset) = 7010.0 kHz. The other station's receiver is tuned to 7008.6 kHz, so my signal on 7010.0 kHz will be heard in his receiver as a tone of 7010.0 kHz - 7008.6 kHz = 1.4 kHz (1400 Hz). Because the other station likely has narrow IF/AF bandpass, he probably won't even hear my 1400 Hz pitch signal when I call. The simple moral to this long-winded story is that you want to always TRANSMIT on or very near the SAME frequency as the other station. If you do that, it won't matter what mode (LSB/USB) or offset the other station is using. The actual receiver frequencies of two or more stations will vary with the offset and sideband mode used by each receiver, but if each station uses the SAME TRANSMIT frequency, everyone will be happy. The way you make this happen on the K1 is: (1) Decide what is a pleasing pitch to you when receiving CW, i.e., the tone you'll just naturally tune to hear another station. (2) Set that pitch into the K1 using the STP menu item. (3) MOST IMPORTANT STEP. Adjust C13 per the manual such that the transmitter offset matches the STP pitch. (4) When tuning in a station, tune for the pitch that is the same as your sidetone. Failure to do this will result in your tuning in stations and wondering why no one hears you when you call, unless they routinely use their RIT to search for off-frequency replies. If you decide later that you want a different sidetone, say 800 Hz, and you set that with STP, this will NOT change the actual offset. You'll have to go back and do the transmit offset adjustment to put the transmitter 800 Hz below the receiver. 73, Mike / KK5F +++++++++++++++++++++++++++++++