[Lowfer] New CMSK Program ... WE2XGR/2 in CMSK mode

[jrusgrove at comcast.net]

Bill

Yes, I would agree with your comments about extremely weak reception in winter time conditions.

That post was also sent to, and primarily intended for, the 600 meter WD2XSH reflector. These guys 
are mainly focused on modes that reliably support emergency comms - especially groundwave. For the 
most part they've been running PSK31 and I'm trying to generate some interest in MSK, which may be a 
better alternative.

Hope you get a chance to take a look for the signal tonight. Let me know if you have a request for 
different power levels or speeds.

Jay W1VD  WD2XNS  WE2XGR/2

> ----- Original Message ----- 
> From: "Bill de Carle" <ve2iq at magma.ca>
> To: "Discussion of the Lowfer (US, European, &amp;UK) and MedFer bands" <lowfer at mailman.qth.net>
> Sent: Thursday, August 05, 2010 9:08 AM
> Subject: Re: [Lowfer] New CMSK Program ... WE2XGR/2 in CMSK mode
>
>
>> At 07:53 AM 8/5/2010, Jay, W1VD wrote:
>>>John W1TAG and I have been testing a 'pre beta' version of CMSK - a  program developed jointly by
>>>ZL2AFP and ZL1BPU/ZL1EE. The beta version has now been released and a description and download is
>>>available at:
>>>
>>>http://www.qsl.net/z/zl1bpu/CMSK/cmsk.htm
>>>
>>>This program was developed specifically for use at LF and MF, runs MSK using a varicode (very
>>>similar to that used by PSK31), and  uses Forward Error Correction (FEC). Initial tests have 
>>>shown
>>>it to be very robust in the presence of static and fading. It's well known that frequency shift
>>>keying work best in the presence of static - amplitude modes, like PSK, do not compare favorably.
>>>Apparently the military realized this years ago as virtually all of their VLF, LF and MF
>>>transmissions are frequency shift keying. John and I have confirmed this with our tests on LF and
>>>MF.
>>
>> There is more to the story and one shouldn't assume MSK is the ultimately superior mode in every 
>> case.
>> While the bit-error rates of PSK and MSK are comparable when signals are relatively strong, in 
>> low static
>> winter conditions when we are trying to copy extremely weak lowfer signals in a more 
>> white-noise-like
>> environment, PSK will increasingly out-perform MSK as the SNR decreases.  I would think at VLF 
>> the much
>> smaller bandwidth of MSK for a given message rate would be the overriding consideration.
>>
>> Bill VE2IQ
>>
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