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

[Artek Manuals]

Dave

If read your post correctly you are saying that you are working against 
an ambient noise level of 20-30 db over S9 is that correct.?

And for starters your measurements are made against that background did 
I understand that correctly?

Trying to keep this simple

Dave
NR1DX


On 8/3/2019 3:28 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
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband 
> Reflector
>

-- 
Dave
Manuals at ArtekManuals.com
www.ArtekManuals.com


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus