Topband: FT8 Observations

[Grant Saviers]

Dave,

Remember that the reported S/N is relative to the receive station noise 
+ QRM level.   Since many TB stations don't have your antennas and have 
high noise, they can't decode you or report a poor S/N.  I get +9 and 
-18 reports from YB stations a hundred KM apart.  It's not spotlight 
prop.  So more power helps. Often I find I need to move TX freq, 
especially way into the FT8 band edges when well heard stations don't 
decode me, but that is more my experience on 80m long path.   The EU QRM 
level is clearly a limiting factor.   I think the latest release decodes 
to -24, I see that sometimes but rarely does the other station respond.  
It is always worth calling since their noise level might be a lot lower 
than mine.  That is clearly the case for some of the skimmer posted 
signal reports by great hearing stations that are not on the air.  I 
will get a -17 report but no other station in that country decodes me 
(or decides to answer my CQ DX).

Grant KZ1W

On 4/22/2018 7:17 AM, David Olean wrote:
> I have been playing around with FT8 on 160M and am a bit puzzled. I 
> have made plenty of contacts, but with many stations, it seems to 
> require an inordinate amount of power to get their attention, or they 
> do not respond at all. I also have noted that I can hear in a 2.8 kHz 
> passband, signals that register from -12 to -17 dB. About the weakest 
> that I see is a bit more than -20 dB. Does this mean that FT8 is only 
> a few dB better than CW?  I have my time set accurately and I try to 
> place my TX signal away from whomever I am calling on a clear spot on 
> my waterfall.
>
> Some stations are easy to work, and I have worked across the country 
> (FN43 to a CM grid) running just 1 watt. It just seems that there are 
> many stations that are not hearing much, but are making plenty of 
> noise.  Am I wrong?
>
> I am working on cleaning up my 160 setup and have 8 beverages running 
> and they are all pretty quiet now that I installed plenty of ferrite 
> chokes around on the RG-6 feed lines.  I am looking forward to next 
> fall and winter.
>
> 73
>
> Dave K1WHS
>
> _________________
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