There should be ONE discreet frequency for FT4 as it is everywhere else, not a range of frequencies.


Once consensus is reached it can be added to the csntechnologies SAT tracker. As of now the frequency proposed by NU1U is in the transponder list for RS-44.






From: Ray Soifer via AMSAT-BB
Sent: Thursday, August 26, 2021 12:58 PM
To: [email protected]; [email protected]
Subject: [AMSAT-BB] Re: FW: FT4 and CW on RS-44


OK John, you've made a persuasive case,  I'll join you in proposing 435.610-620 for FT-4 if users keep their  EIRP down to no more than half of what they run on CW or PEP on SSB.


73 Ray W2RS


-----Original Message-----
From: Carlos Cardon <[email protected]>
To: [email protected]
Sent: Wed, Aug 25, 2021 10:50 am
Subject: [AMSAT-BB] FW: FT4 and CW on RS-44un

CW and other digital modes at the bottom of the receive bands seems like a good idea (and easier for us old HF guys to remember..). 






From: Carlos Cardon [mailto:[email protected]]
Sent: Monday, August 23, 2021 12:41 PM
To: '[email protected]'
Subject: RE: [AMSAT-BB] FT4 and CW on RS-44


Well said, John. 


For us old guys, it seems consistent to have CW and Digital at the lower end of the band and SSB in the upper part.  The CW and digital signals require much less bandwidth than SSB.  So if they can set up and look for each other at the low end, we can avoid some of the QRM we have been hearing.





From: [email protected] [mailto:[email protected]]
Sent: Monday, August 23, 2021 9:47 AM
To: [email protected]
Subject: [AMSAT-BB] FT4 and CW on RS-44


FT4 activity on RS-44 has been increasing.  FT4 can be heard just about everywhere in the passband and this can create problems for SSB and CW users.  I have heard FT4 around 435668, 64x,639 and 620.  The HF bands are divided into mode segments so CW,SSB and Digital are not in the same areas.  On RS-44 there are no segments so it is all modes everywhere.  Several days ago I listened to WB9YIG trying to work N1DM around 435639, but every time N1DM would give his callsign a FT4 signal would be on top of him.  They finally gave up.  I doubt if it was intentional.  The FT4 computer was just doing what it was programmed to do.  The operator may have not even been listening (not a good idea on sats). Also keep in mind that a FT4 signal is key down continuous carrier, much more demanding on satellite power than SSB or to some extent CW. The beauty of FT4 is supposed to be that you don't need a strong signal to decode, so flea power should work well.

It would be good if all the FT4 operations would move to one area on the transponder. I suggest 435610-435620 because it is the least used area.  The top end has become very crowded lately due to some rovers operating in that area.  This has encouraged others to operate there as well.  Maybe some others have a better suggestion.

FT4 is not the only issue on RS-44.  CW activity has been increasing as well.  CW and SSB can co-exist, however, CW ops cannot be using CW filters and expect not to interfere with SSB stations.  Again we don't have a CW segment so using CW filters are not going to be appropriate.  Please use a SSB RX filter when operating CW and make sure you don't hear SSB in your passband before starting up.  Same for SSB stations.  Don't start up if you hear CW in your passband.  Just move to a clear spot.

If you are not computer conrtolled for doppler, you are going to be moving in the passband  And you are likely going to slide into another QSO, especially now that RS-44 activity has increased. Please try to keep your position in the passband stable.  If your radio can be computer controlled, please take advantage of that so that you don't move.  You never have to send dits, whistle or blow into the mic when you are computer controlled.  And you won't be transmitting on top of somebody.

Just my opinion of course. 

73, John K8YSE 




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