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Re: [RTTY] Looking for an interface - a few simple requirements

To: rtty@contesting.com
Subject: Re: [RTTY] Looking for an interface - a few simple requirements
From: Robert Chudek - K0RC <k0rc@citlink.net>
Reply-to: k0rc@citlink.net
Date: Wed, 02 Oct 2013 11:50:43 -0500
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
The CW paddle sent RTTY from an Elecraft K3 is one possible source of "slow RTTY". Another, as has been eluded to, is the settings within some software.

I am going to describe two tests you can run for yourself. This involved using MMTTY as a stand-alone software. Actually, two separate MMTTY installations on one computer. (Installed in C:\MMTTY1 and C:\MMTTY2 - which allows independent configurations.)

The first test is see how much difference there is between 45 and 45.45 baud. Start one instance of MMTTY and set the Baud setting on OPTIONS > Setup Options > Decode > BaudRate > 45. Start the second instance of MMTTY and set the Baud setting to 45.45 Baud. Now back on the main RTTY window click the TX button on both instances of the software. You should hear diddles from both versions, and when you listen "closely", you will hear the beat of the "ticks" move in and out of synch very slowly. As has been stated, without test equipment, it will be impossible to hear the difference in speed between 45 or 45.45 Baud on the air.

The second test is to recreate "Slow RTTY". Following the menus OPTIONS > Setup Options > TX, near the top center are two sliders named "Char Wait" and "Diddle Wait". Normally these sliders are full left (as they should be). Move the "Char Wait" slider to the far right. Now click the TX button on the MMTTY main window and listen to the paced "tick" of the diddle. I am guessing it's about 3 or 4 ticks per second. And of course you can move the slider toward the left and decrease the delay between characters sent by MMTTY. This slider provides the "opportunity" for someone who doesn't understand it's impact to nudge it slightly to the right, unknowingly creating "Slow RTTY" on the air.

My mileage varies (between 25 and 28.5 mpg).

73 de Bob - KØRC in MN

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On 10/2/2013 10:26 AM, Jay WS7I wrote:
That's not quite right, Chen. Slow RTTY has been around for quite a while. Comes from improperly set up software programs most of which were around a lot longer than K3's and there weird paddle. Not the Microham stuff either.

In fact I had it once using MMTTY at a place where I contest on occasion. This was an old MMTTY setup on a Win98 box. Solved that my updating Writelog, the computer to something newer and a newer version of MMTTY.



On 10/1/2013 5:38 PM, Kok Chen wrote:
I had earlier written to Peter that although the MicroHam interfaces cannot achieve precise 45.45 baud transmission, that the hardware cannot be the cause of any of the "slow RTTY" that we hear -- simply because I have never heard "slow RTTY" come from my uH Router program. If it were a hardware problem, I will have problems too.

I would challenge any "golden ears" to tell the difference between 45.45 baud and 45.0 baud (and you can actually get closer to 45.45 than 45.0 with a MicroKeyer if you program the division ratio correctly -- presumably all software is doing that already). Heck, the majority of RTTY ops cannot tell the difference between 1 stop bit and 2 stop bits and the character rate difference is much larger there. Due to because of the extra keying sidebands it is actually easier to tell 1.5 stop bit from 1 stop bit.

The most likely cause of the "slow RTTY" are Elecraft K3, running in FSK-D and keyed by using a Morse paddle (yes, the Amateur community spans a range of intelligence :-).

MicroKeyers have been in existence for a long time and no one noticed "slow RTTY" until Elecraft implemented FSK-D wrongly (by not immediately issuing a diddle while the op is in the middle of paddling in a long Morse character like a zero or a 9).

73
Chen, W7AY


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