[Elecraft] K3 Firmware 2.10,1.81 problems Update

[Jack Smith]

Those of us who have been around RTTY before the days of electronic 
printers remember the second meaning of LSMFT - low space means fine 
teletype. (refers to the RF frequency, not the demodulated audio of course.)


Jack K8ZOA
www.cliftonlaboratories.com


Joe Subich, W4TV wrote:
>> RTTY was based upon the frequency 
>> of Mark (2125) and Space (2295) and the surplus military 
>> equipment available, unless you could afford some of the high 
>> dollar HAL equipment (which was also used by the military). 
>>     
>
> No, RTTY is always "Shift low" - that is Mark is the HIGHER 
> RF frequency and space is the LOWER RF frequency.  When the 
> audio tones 2215 and 2295 are applied to a LSB transmitter 
> in AFSK this results in the correct shift. 
>
>   
>> I have no idea what the protocol is for DATA (perhaps Elecraft 
>> can tell us.)  As an experiment, try switching rigs in MixW and 
>> observe what is happening to the signal frequency.  
>>     
>
> FSK D and AFSK A receive in LSB while PSK D and DATA A receive in 
> USB for compatibility with the (backward) convention of most non-
> RTTY software writers (PSK32, MFSK, etc.). 
>
> 73, 
>
>    ... Joe, W4TV 
>  
>
>
>
>
>   
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Rich (KE0X)
>> Sent: Friday, June 27, 2008 4:49 PM
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] K3 Firmware 2.10,1.81 problems Update
>>
>>
>>
>> As Julian suggested the problem is in MixW.  It has been 40 
>> years since I had the RTTY training course in the NAVY, but, 
>> it has to do with the convoluted history of RTTY.  Although 
>> SSB is on the LSB on the HF bands below 30 Meters and USB on 
>> those bands above 30 meters (Many reasons given for this most 
>> of which are not correct) RTTY was based upon the frequency 
>> of Mark (2125) and Space (2295) and the surplus military 
>> equipment available, unless you could afford some of the high 
>> dollar HAL equipment (which was also used by the military).  
>> Military protocol was to have the Mark the lowest tone in 
>> frequency. This was ok with most equipment made BPC (Before 
>> Personnel Computers).  The PC brought out the conversion of 
>> telephone modems, use of the modem IC’s and finally the PC 
>> sound card for generating these tones. If you built a TNC out 
>> of a modem chip and did not include a reverse switch you were 
>> stuck to either the low or high bands.  This was fixed on the 
>> PC with a button to reverse the signal that you could click 
>> on and copying.  Some of the Rigs treat RTTY as SSB, others 
>> put RTTY so that the Mark is always the lowest frequency 
>> transmitted regardless of the band selected, and RTTYR 
>> reverses this.  I have no idea what the protocol is for DATA 
>> (perhaps Elecraft can tell us.)  As an experiment, try 
>> switching rigs in MixW and observe what is happening to the 
>> signal frequency.  You wil not be able to chang frequency 
>> with MixW but you can see what happens to the signal as you 
>> turn the dial on the RIG.
>>
>> Rich,
>> KE0X
>>
>>
>> -- 
>> View this message in context: 
>> http://www.nabble.com/K3-Firmware-2.10%2C1.81-problems-Update-
>>     
> tp18154703p18163577.html
> Sent from the Elecraft mailing list archive at Nabble.com.
>
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