[MRCA] Teletype shift

[Ray Fantini]

I just pulled up 97.305 and 97.307 and I don’t see where there is any issue running 850 Hz shift, especially if it’s FSK. ASFK may be an issue with an overdriven transmitter but for me I don’t see any problem.  There may be ethical issues regarding use of wide shift in a world of narrow shift but as far as I am concerned I am working with vintage technology and if they don’t like it so what? Lot like the issues we have using USB on 40 and 80, its contrary to convention but within the confines of what I and others who are like minded are doing it’s what we want to do.
Modern Hams can use narrow shifts and plug ins for their SDR that allow them to run RTTY or any number of digital protocols and I have no issue with that, it’s truly amazing what can be done with a sound card, software and radio, but I have no desire to do that myself.
What I am doing is attempting to operate obsolete technology that may have been significant fifty years ago but is largely forgotten today in a way that it was intended to be operated.
This reminds me of the argument regarding the use of AM, the FCC will mandate only using the bandwidth necessary and looking at that one would assume that there is no place for a mode that produces two sidebands and a carrier where its accepted practice to use one sideband only in HF communications but AM as a mode has survived and continues to be around. I have myself operated that inefficient mode and intend to be operating it in the future using vintage equipment of course.
Beyond 97.307(3) limiting RTTY to 1.0 KHz or less and the 2.8 KHz restriction on the 60 Meters channels my limited understanding is that the FCC requires you to use only the bandwidth necessary for communications. Unlike the LMRS/Broadcast service that sets strict limitations on bandwidth use.
So I am going to go ahead and beat the drum for a “vintage” teletype net on 40 that will be 850 Hz shift.

Ray F/KA3EKH




From: Rob Flory [mailto:farmer.rob.flory at gmail.com]
Sent: Friday, March 15, 2019 6:49 AM
To: Tim <timsamm at gmail.com>
Cc: Ray Fantini <RAFANTINI at salisbury.edu>; Military Radio Collectors Association <mrca at mailman.qth.net>
Subject: Re: [MRCA] Teletype paper

Tim,
Thanks for the reply about shifts and practices.  Have fun!
RF

On Thu, Mar 14, 2019 at 6:24 PM Tim <timsamm at gmail.com<mailto:timsamm at gmail.com>> wrote:
Hi Rob -  Good question...Part 97.305 (f)(3) authorizes RATT with any shifts of less than 1 kc where amateur RATT is authorized. As to whether that would annoy anyone else on the band, different story.
We have been running 80/40 meter 850 cps shift signals on Saturdays for the past 3+ years and have had no complaints that I am aware of.  The only significant RATT users are on contest weekends (we avoid that bedlam) but now also FT8 and some other very narrow bandwidth stuff...  With the filters necessary I doubt we would annoy anyone else, especially for occasional tests or QSO's...
I have also monitored the circuit in use with an independent receiver running fldigi which can decode 170 cps shift  RATT or nearly anything else and have not seen any apparent interference potentials...but something to be aware of...
TNX..
Tim
N6CC

On Thu, Mar 14, 2019 at 2:10 PM Rob Flory <farmer.rob.flory at gmail.com<mailto:farmer.rob.flory at gmail.com>> wrote:
What do the regs have to say about TTY shifts?  There are times and frequencies where 850 would be seriously frowned upon socially if not legally for the amount of bandwidth used.

RF

On Thu, Mar 14, 2019 at 1:25 PM Ray Fantini <RAFANTINI at salisbury.edu<mailto:RAFANTINI at salisbury.edu>> wrote:
That's what happens now, I can get one leg of the "X" or the other but not both together. Just have to convince others to try old school 850 Hz, have MITTY on a computer and can do TTY that way just after having to work on computers all day at work have no desire to play with them on my time off. Not unless they are at least thirty to forty years old first. The goal is to get al this stuff up and working in its original configuration.
Also did try to join into "Greenkeys" again and once again the same results- not a word back.
What's the status of TTY opps in the Bat Cave? What about you're GRC-19? Got the modem for that? There will have to be a special prize if not just bragging rights for the oldest operational system when we do the net.
Anyone can do a rice box with a laptop so they would score something like a 0.5, modern radio with Ham TTY codec and teleprinter would be 1.0, and any military radio with teleprinter will be 10.0 with a multiplier of 2 for every decade of service. Weighing the scoring table like that a GRC-19 with mechanical teleprinter would score 50 or 60 points!

Ray F/KA3EKH

-----Original Message-----
From: mrca-bounces at mailman.qth.net<mailto:mrca-bounces at mailman.qth.net> [mailto:mrca-bounces at mailman.qth.net<mailto:mrca-bounces at mailman.qth.net>] On Behalf Of B. Smith
Sent: Thursday, March 14, 2019 12:44 PM
To: Military Radio Collectors Association <mrca at mailman.qth.net<mailto:mrca at mailman.qth.net>>
Subject: Re: [MRCA] Teletype paper

   And yet another brain fart, take a signal generator and pick a center frequency and slowly sweep up and down to check the limits of the "X"
display.
Z

On 3/14/2019 12:09 PM, B. Smith wrote:
> ARRL uses 170 cycle shift at 45 baud (60 WPM). I assume that since you
> are using your MD-522 in a "850" cycle mode you are required to
> straddle tune the signal. My guess is if you are exactly centered on
> the signal with equal space and mark then since the display depends on
> the mark and space filters then  the mark and space frequency is out
> of the pass band and you will not get a decent "X" display. Solution
> is modify the modem or use the audio output for a add on display.
> Perhaps Another solution is just copy mark or space only. You will
> probably have to modify the modem anyway for transmitting 170 cycle
> shift? I would join the Green Keys list and post some questions there.
> Z
> You can do a search for 8.5 inch "roll" paper.
>
>
> On 3/14/2019 9:02 AM, Ray Fantini wrote:
>>
>> Inching closer and closer to having the UGC-74 and MD-522 up and
>> running. Have paired them with a Harris RF-350K in the shack right
>> now and after I get this all working will be looking at building up
>> cables for use with the mutt and the GRC-106.
>>
>> The two new problems is that I have been having a hell of a time
>> trying to copy the ARRL bulletins in that I can pick them up but just
>> can't seem to get the correct tuning display when doing that. This is
>> with using the 850Hz mode. The other issue is I just ran out of paper
>> last night and need a roll of teletype paper and wanted to know if
>> anyone had a roll or two they can spare.
>>
>> Ray F/KA3EKH
>>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20190315/bf9d6e49/attachment-0001.html>