FT-991 Data mode, Audio bandwidth and offset experiences with JT65

Discussion in 'General Technical Questions and Answers' started by G6GEI, Apr 23, 2016.

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  1. G6GEI

    G6GEI XML Subscriber QRZ Page

    Firstly I love the FT-991 which I recently upgraded to from my old FT-847. But I have had a nightmare overcoming some issues with it when working JT65, I use WSJT-X v1.6.

    Firstly with the FT-991 set to Data Mode I found the frequency I had to set was 1Khz higher than I expected, which was ok, except that WSJT-X likes to prevent you using JT modes in sections it thinks are reserved for WSPR, but actually I wasn't in those sections.

    Secondly I found there was a narrow audio bandwidth indicated by more noise on the edges of the waterfall compared to my FT-847 or FT-817. I tried setting the menu item 062 DATA MODE to OTHERS as suggested on other postings, but the audio bandwidth was then even worse...

    To keep this post short, this is what I ended up doing and all is now well. the following menu items....
    062 DATA MODE = OTHERS
    064 OTHER DISP (SSB) = 1500 Khz This corrects the frequency display
    065 OTHER SHIFT (SSB) = 1500 Khz This widens the audio bandwidth
    066 DATA LCUT FRED = OFF
    068 DATA HCUT FREQ = OFF
    070 DATA IN SELECT = REAR
    071 DATA PTT SELECT = RTS I guess this depends on your rig control options, I use HRD with RTS
    072 DATA PORT SELECT = USB

    As far as the ALC level adjust I just TX and adjust the audio out level until there is no ALC. What I do find is this setting varies depending on the audio frequency used which is odd.

    I also find that if I adjust the output level to set a power output of say 10W, that after a few minutes of operation the 10W has dropped to 7 or 8 and I have to increase the audio out to get it back to 10 and there is still no ALC. I find this strange and a little worrying, not sure if this is a feature or a fault with the rig. It seems to operate fine on SSB voice. I guess it doesn't matter, there being no real difference between 7W or 10W in the real world.

    Hope this helps someone.
    73s Tim. G6GEI
     
  2. M0GVZ

    M0GVZ Ham Member QRZ Page

    Thanks Tim, most certainly does. Had some issues with the offsets for CW as well as most rigs use the dial frequency, not the offset when click'n'tuning from software.
     
  3. K0DSL

    K0DSL Premium Subscriber QRZ Page

    Tim, I have seen these same settings elsewhere, and am wondering what your settings are for --

    031 Cat Rate, 032 Cat TOT, 033 Cat RTS, and what baud rate are you using. I too have an FT-991, which I upgraded to the FT-991 with the firmware update. I have not been using a interface, but have a Signalink if all else fails. I see signals in the waterfall, when I change frequency ion the radio the frequency in the software changes, and when I send a CQ, the software toggles the radio into transmit. My problem is it is not decoding signals, I see no call sign data in either window. I have tried several other settings I have found on the internet, but still no luck.

    73, Diane K0DSL
     
  4. G6GEI

    G6GEI XML Subscriber QRZ Page

    I have since sold my 991 and replaced it with an Icom 7100 as it offered the remote head for mobile work. The 991 was a good radio but my preference is the 7100 even though it has no waterfall display like the 991.
    Tim
     
  5. K6BRN

    K6BRN XML Subscriber QRZ Page

    Tim:

    I run JT-65 and JT-9 on an FT-991 all the time (as well as an FTDX-3000)

    I get about 3 KHz of usable bandwidth out of the radio for this application. There IS a pronounced falloff at the edges of this bandwidth and the FT-991 frequency displayed is offset from the WSJT-X display unless you program the WSJT-X offset as you described.

    To maximize audio bandwidth for JT-65, make sure the roofing filter selection is as wide as possible, then set the digital mode filter slopes and cutoffs as gentle and wide as possible, even though you've set their enable to "OFF". The Yaesu menus do not always behave as you would expect them to. In particular, the FSK mode settings seem to affect "Other" operation, too, at least in my firmware version. Next, make sure the variable bandwidth control (essentially PBT) is set as wide as possible.

    The ALC level at the radio should read about 50%, not zero. A 50% setting will stabilize output power, especially if you are operating near the audio passband edges. You will need to re-adjust levels as you move from one end of the audio pass band to to the other. I've examined FT-991 output with a spectrum analyzer and found the output signal purity to be just fine with ALC at 50% - no IMD death rays shooting out of the antenna connector.

    Sorry I'm not more specific, but I'm on a trip right now and do not have immediate access to the radio and manuals.

    But you should know that the FT-991 works very well on JT-65 and JT-9.

    Best Regards,

    Brian - K6BRN
     

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