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[VE3VEE]

Me and my friend have our transceivers tuned to the same frequency. However, the DX station I hear on +994, he decodes on +1994. Also, when my friend transmits on +2663, I decode him on +1663. Everything else appears to be working just fine on both of our setups, we just noticed this anomaly now. Does anyone have any explanation? Again, yes, our transceivers are both set to the same frequency, as strange as it may seem.

Marvin VE3VEE

[K4LIX]

I can make this happen very easy on my radio (IC-7700) and I do it quite often.  Let's say I receive a station on 14.074, USB, on 200.  That is a bit low for my 3.0 I.F. filter, so I just spin the dial to 17.073 and the station that was on 200 is now on 1200, much nicer for my 3.0 I.F. filter.  Maybe you and your friend are 1MHz apart in your main tuning.

[VE3VEE]

No, both of our transceivers were tuned to the same frequency. I actually asked him to take a photo of his laptop monitor and send it to me. His frequency in the WSJTX software was the same mine. It's a mystery to me. Not sure yet how this is possible.

Marvin VE3VEE

[W9IQ]

What are the "split operation" settings on both stations? What radios are being used?

- Glenn W9IQ

[K0UA]

Me and my friend have our transceivers tuned to the same frequency. However, the DX station I hear on +994, he decodes on +1994. Also, when my friend transmits on +2663, I decode him on +1663. Everything else appears to be working just fine on both of our setups, we just noticed this anomaly now. Does anyone have any explanation? Again, yes, our transceivers are both set to the same frequency, as strange as it may seem.

Marvin VE3VEE

One of you is operating a Yaesu with a 1Khz offset set in the menu.

[VE3VEE]

James, you may be correct. He has a Yaesu FT-1000 MKV. I will ask him to check the setting tomorrow (it's 3 am now in his time zone).

Marvin VE3VEE

[K6BRN]

One of you is operating a Yaesu with a 1Khz offset set in the menu.

Bingo!

It's pretty easy to TX slightly off the intended frequency in FT8 - either due to simply "hitting the knob" or due to different pre-programmed offsets between radios. 

WSJT-X can accommodate built-in radio default TX offsets by using the:

Settings (menu) -> Frequencies (menu) -> Frequency Calibration (data entry frame) ->Intercept (entry).

For my Yaesu radios (FTDX-3000 and FT-991, also works for FTDX-1200) I set the INTERCEPT to 1,000 Hz and SLOPE to 0.0000.

Note that I also LOCK the VFO dial during FT8 operation to avoid unintended frequency changes and I also operate using "split/Fake It" operation" under the Settings -> Radio tab.

Just to be sure, I have a real-time frequency counter/sampling head in line with my power meters to ensure I'm TXing exactly where I should be.  This is more of a safety measure I put in place for operation on the channelized 60M band, where TX frequency accuracy is pretty important.

Brian - K6BRN

[K3TN]

Another way this can happen: some radios, like my K3, give you choices of mode to use for data: LSB, USB or a data mode. That can make the center freq be different as well.

73 John K3TN

[VE3VEE]

Thanks to everyone for very valuable feedback. My friend has solved his issue. He uses a Microkeyer device and upon inspection of his settings he discovered he had a 1000 Hz offset in his settings there. The default was supposed to be 0 Hz and he cannot recall when and why he changed it to 1000 Hz. He now changed it to 0 Hz and all seems to be fine.

Marvin VE3VEE

[K0UA]

Cool.  Tnx.