Topband: FT8 on 160 - how you can make a difference

[W0MU Mike Fatchett]

Have you attempted to open a conversation with the creators of the mode 
and discuss what you are seeing?  They seem like they are quite 
knowledgeable.  How can you disprove their claims of weak signal mode 
when you are not sure how they are coming up with their numbers?

I never heard EU or JA on 160 until I tried FT8 last year.  I never once 
heard any dx on CW last season although many tried as the devout 6M ops 
have a chat room where there were countless tries on other modes but 
only contacts made on FT8.  Why is that?  No longer do you have to have 
stacks or H frames to work Gud DX on 6m.

W0MU


On 8/3/2019 1:28 PM, K4SAV wrote:
> There is growing trend on 160 that I find disturbing and that is for 
> major DXpedition to use FT8 for all or mostly all 160 operations. They 
> do that because they "know" that FT8 is ideally suited for weak signal 
> operation.  They have read that and are continually told that by 
> everyone.  Rare countries on 160 is synonymous with weak signals and 
> poor signal to noise ratios.
>
> I know of no one that has done the same tests that I posted to 
> Topband.  I have had people agree with me but that was because they 
> liked my answers, not because it agreed with their measurements.  I 
> have had many people tell me I am wrong and they sited the official 
> documentation as proof that my measurement were wrong.
>
> So if you would like to join the ranks of myth busters, start doing 
> some measuring.  WARNING, Myth busting of all types in ham radio is a 
> never ending effort.  As soon as you bust one, two posts later someone 
> will repeat it again. Sorry, I don't have any caps, pins, or t-shirts 
> to sell.
>
> If enough people start characterizing this mode maybe the more 
> experienced people in radio will sit up and take notice.  One or two 
> posts by a single person isn't going to do it.
>
> You are not going to kill FT8 no matter what you do or how feel about 
> it.  It will always be a home for those they can't copy CW, and for 
> those that don't like CW, and for a few others for a variety of 
> reasons.  I can't see a problem with that.  The problem I see is with 
> FT8 and major DXpeditions.  I also see some FT8 only DXpeditions but 
> those are usually vacation part time to non-rare countries.  Can't 
> worry about those.
>
> For people that can't copy CW, FT8 is very attractive.  It will allow 
> them to work some DX on 160.  In the winter I see Europe appearing on 
> FT8, so that can be worked from the eastern US. Invariably when I 
> measure the strength of those stations, they are close to S6.  That 
> would be arm chair copy on CW with a receiver that sits on S1 on noise.
>
> So contribute to the ham radio knowledge data base by making some 
> measurements.  I described my measurements in a previous post. 
> Figuring out what the reported S/N number means is interesting but the 
> more important question is what is the minimum signal to noise ratio 
> this mode will decode.  Sitting up a test for minimum signal is a 
> little tricky because there are so many FT8 stations on at any one 
> time, there is almost never a nearly dead band.  I simulated that on 
> 160 by waiting until the first stations from the NE showed up on the 
> band (just after their sunset) and turning my antenna away from them 
> so as to decrease their strength and bring up the noise from other 
> directions.  When I wait until sunset occurs in more locations, my S 
> meter hangs at about S9 +20 to 30 dB no matter which direction I point 
> my antenna.  I tried doing this on 6 meters but often there was 
> nothing there. I suggest doing measurement first in normal decoding 
> mode, then test what it does in deep search mode.  Be careful how you 
> switch modes.  FT8 likes to memorize the band and make guesses in deep 
> search mode.
>
> You can try doing the minimum S/N test in a crowded band instead of a 
> nearly dead band but I don't think you will ever find it decoding a 
> weak signal.  You have to measure the noise levels and signal levels.  
> You can't use the reported S/N number.
>
> If you make some measurements, post them.  I would really like to hear 
> what others find, especially if they happen to disagree with what I 
> measured.
>
> I don't have a pony in the dog and pony DXCC race so I don't have an 
> opinion there.  I love working DX on 160 but collecting cards was no 
> fun.  So years ago I decided to only do the fun part.  I compete with 
> myself, no one else, and I don't get bragging rights, but I don't do 
> this for bragging rights.
>
> Jerry, K4SAV
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