Topband: Digimodes

[Tom Rauch]

Hi Bill,

I'd like to do some weak signal CW to PSK comparisons with 
someone, with really weak signals!  

I'd also like to apologize for the manners of some ops. I do know for 
a fact there are people, both SSB and CW ops, who for some 
reason intentionally aggravate PSK ops.

> Many times CW ops on 160 will either totally ignore users
> of other modes or, are completely ignorant of internationally
> recognized frequencies (by gentlemen's agreement) modes such as
> PSK31, MFSK16 and Hellschreiber.  Or, they just don't ask if the
> frequency is in use.

Software for digimodes, as you know, mostly suggests 1838kHz 
with some software only having a footnote to look at IARU 
bandplans! Many other ops have no idea what the noises are, let 
alone where they are supposed to operate. It is mostly a matter of 
education, and with patience PSK will be well established below 
1810. (Tonight while I was working on 1826.5, a PSK station 
started on 1828 or so, hi hi!) 

Part of the problem with QRM might be that PSK ops often use 
SSB filters, and CW ops often use 500 Hz filters. They might have 
no idea they are desensing your receiver.

I can't understand why digimodes less than 100Hz wide have to 
use 2.1kHz filters. That just sets the system up for dynamic range 
problems. I get much better print on weak signals using a 500Hz 
filter, even in the total absence of QRM!


73, Tom W8JI
W8JI@contesting.com