Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

On Thu,2/18/2016 6:30 PM, Mike Murray wrote: If I recall correctly, the main signal was around S9 and the image at S7 or so. I agree with W4TV that there is some sort of a setup problem. Things to check: the assignment of the roofing filters, the settings for the roofing filters, the

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Don, as described that was NOT the opposite sideband. On the video the stronger signal was at 14091.883 kHz on the dial. That is the frequency of the mark tone; the space tone would have been at 14091.713 kHz. The pitch in use was 915 Hz mark, so the suppressed carrier frequency would be

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Don, If I recall correctly, the main signal was around S9 and the image at S7 or so. Mike On Thu, Feb 18, 2016 at 5:30 PM, Don Wilhelm wrote: > Mike, > > For strong signals the filtering may let some of the opposite sideband get > through the filters. > What is the

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Mike, For strong signals the filtering may let some of the opposite sideband get through the filters. What is the relative S-meter reading for the true sideband and the opposite sideband? 73, Don W3FPR On 2/18/2016 11:56 AM, Mike Murray wrote: After doing some more testing in last weekends

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Are you *absolutely sure* you are using the 400 Hz IF filter? By ear, it sounds as if you have a wider IF filter that is centered on the carrier and allowing the image to reach the DSP. Since your display shows FL4, is it possible that you have all your filters reversed? 73, ... Joe, W4TV

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

After doing some more testing in last weekends RTTY contest, it appears that I made an erroneous statement as to what I was hearing and where. What I found is that as I tune down in frequency and find a signal that will decode, if I then tune down another 170 Hz I'll hear the inverted signal.

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Mike, That effect should have nothing to do with the 1.8kHz filter. I would go with Lyle's suggestion that it is the AGC that is allowing you to hear the opposite sideband of strong signals. To give that suspicion a quick check, turn off the preamp and add attenuation, then reduce the RF

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Maybe. The K3 offers so many ways to configure things, not all combinations are guaranteed to be optimal. You might also try not using the dual PB DSP, my experience has been that MMTTY and 2TONE decode a bit better without it. I have the "stock" 2.7 KHz filter, and a 5-pole 500 Hz. I

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Assuming that when the OP says "tuning" he is turning the VFO knob, then here's my take. All of the worry about roofing filters (gad how I hate that term) is for nothing. The crystal filters in conjunction with so-called hardware AGC are there to protect the delicate 2nd mixer from overload in

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Joe, et.al., I finally got back to the shack to check the setup. It looks like I was actually using a 1.8 kHz SSB roofing filter in conjunction with the 500 Hz dual PB DSP filter. I also checked the filter offsets which were all at 0.0 (all 8 pole) and I was using AFSK A mode. Is the effect

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Seems strange to me. Don't or haven't noticed it with my K3S. I would think they perform about the same in this regard. 73 Bob, K4TAX On 1/6/2016 10:40 AM, Mike Murray wrote: I played a bit in the RTTY RU this weekend with my new-to-me K3 to learn the operation and iron out any kinks in my

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

It sounds to me as if you have selected an inappropriate roofing filter or have improperly configured the filter offset. What roofing filter are you using and what [DSP] bandwidth? 73, ... Joe, W4TV On 1/6/2016 11:40 AM, Mike Murray wrote: I played a bit in the RTTY RU this weekend

[Elecraft] K3 - AFSK anamoly? No replies, try again

I played a bit in the RTTY RU this weekend with my new-to-me K3 to learn the operation and iron out any kinks in my setup. Everything worked well except for a problem (?) on receive. I was able to easily tune in signals and copy using MMTTY, but when I tuned to the other side of zero beat I could

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

I saw your original post. Im not sure I understand your question. If you to the point where you are correctly lined up on both frequencies and getting good decode as " zero-beat", yes you can hear the tones and possibly even decide when listening to only one tone. Sent from my iPhone ...nr4c.

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

This sounds like a crystal filter offset setting is incorrect. (Also check to make sure your IF shift setting on the front panel is not set to an extreme.) Check the setup menu entry for each crystal filter and its offset setting. 8 pole filters should be set to a zero offset. 5 pole filters

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Mike, If you do find it is AGC that is producing that 'unwanted sideband' response, you may want to investigate your AGC slope and threshold settings. To give you some guidance, look at my webpage www.w3fpr.com article on "Noisy K3". I would suggest that you set those AGC parameters in CW or

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Mike, Is the mark tone in MMTTY set to the same frequency as you have set in the K3? IIRC, the default mark tone in MMTTY is 2175. 73, Don W3FPR On 1/6/2016 6:47 PM, Mike Murray wrote: Bob, Joe, Bill & Mike, Since I'm new to RTTY, I probably didn't describe my question in correct

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Bob, Joe, Bill & Mike, Since I'm new to RTTY, I probably didn't describe my question in correct terminology - I mainly only operate CW. I'll try again I'm using DATA A/AFSK A, setup for low tones (915/170) and the RTTY dual-PB filter. To illustrate what I'm hearing/seeing, imagine tuning

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Mike, It could be that the band is quiet, this is a strong signal (S7 or more) and as you tune through to the opposite sideband the AGC is kicking up the gain so you hear the signal down some 70 dB or so, but if it is a strong signal on an otherwise fairly quiet band, you may hear it. 73,

Re: [Elecraft] K3 - AFSK anamoly? No replies, try again

Since I'm new to RTTY, I probably didn't describe my question in correct terminology - I mainly only operate CW. I'll try again And I'll ask my questions again ... what *ROOFING FILTER* and what DSP bandwidth are you using? As Eric said in reply to your posting, this sounds like the