Topband: FT8 on 160m

[W0MU Mike Fatchett]

The normal bandwidth for FT8 is 2.5 to 2.8 kc.  at 1.842.9 you should 
have been outside the FT8 band.  Hardly anyone operates above 2.5 it 
seems anyway.  I think you  were essentially being trolled.  I suppose 
you could have been pretty wide for a local or close in station wiping 
out a fair portion of the upper end of the band.

I am usually on 160 FT8 every night but I took the weekend off for the 
contest from FT8.

Too bad the guy did not identify.  I noticed a few freq cops on the 
cluster announcements where some FT8 users think they deserve clear 
space which we know does not exist is a shared band that we have.

W0MU


On 11/27/2017 2:17 PM, Tim Shoppa wrote:
> As a practical matter there are several 2 kHZ segments of each band that are now devoted to 24x7 JT65, FT8, and other digital modes. Weak signal CW work - eg working rare mults or even just weak guys from common mults - in those segments just isn’t gonna happen.
>
> Substantial parts of 80M and 40M have been pretty bad for several years now with SAILNET and other automatic modes.
>
> Tim N3QE
>
>> On Nov 27, 2017, at 3:43 PM, Roger Parsons via Topband <topband at contesting.com> wrote:
>>
>> As we all know, CQWW produces huge activity on all HF bands. This year I was hearing stations up to well above 1850kHz. I have found that trying to run Europe is often more productive in the 1840-1850 segment, presumably because it is less crowded than lower in frequency.
>>
>>
>> Late in the contest I started to CQ on about 1842kHz, and after a while, and several QSOs, was told (on CW): "Please QSY. 1840 is reserved for FT8. Good luck in the contest." Ignoring the fact that nobody has a reserved frequency on any band, I thought OK, don't want to upset anybody, and moved to 1842.9kHz. Shortly, the same message arrived.
>>
>> My (probably incorrect) understanding is that FT8 stations are using USB with a carrier frequency of 1840kHz. So a CW station on 1842.9 should be out of their passband. I did listen carefully and could not hear any FT8 transmissions above 1842.2. (I have multiple receive antennas in a very quiet location.)
>>
>> I believe that FT8 transmissions in principle use a microscopic bandwidth, but it appears they actually need a wide clear channel.
>>
>> Yes? No?
>>
>> 73 Roger
>> VE3ZI
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