[RTTY] Calibration

Wed Mar 4 21:35:17 PST 2009

Man am I glad I got rid of those Kenwoods that Blegen forced me to take 
home!

73
Jim W7RY

----- Original Message ----- 
From: "Jay" <ws7i at ewarg.org>
To: "'RTTY Reflector'" <rtty at contesting.com>
Sent: Wednesday, March 04, 2009 8:07 PM
Subject: Re: [RTTY] Calibration

> That of course is true, however, there could be potential for a problem
> that some might well encounter. 915 x 2 is 1830 and 915 x 3 = 2745 so
> the potential for one and possibly two images could occur and pass
> through the transmitter under certain conditions.
>
> That is of course one of the reasons why the original 2125 - 2295 was
> chosen fits but harmonics don't go through as easily.  Seems also that
> 88 mH torroids might have played a role as well.
>
> Interesting thing playing with rtty signals. I have been messing with
> the DM 780 and trying 23 Hz shift out on a MARS frequency.  From 850 to
> 425 to 170 and now to 23 Hz.  Lots of fun.
>
> Oh, and for the FSK purists a little story from a few years back.
>
> One day Hal and I were fired up operating the SARTG contest,  We were
> using some old Hal Keyboards for typing on and I believe an old Flesher
> TU-170 for the terminal unit.  Hal had a pair of Kenwood Twins which
> were as I always told him, poor man's Drakes.  The Kenwoods were driving
> an old Johnson "Thunderbolt" amp which was a amp that ran class AB1/AB2
> on teletype.
>
> Anyway we were doing a Multi-single and I was logging the contacts as
> Hal worked the stations.  We swapped off this from time-to-time.
>
> Hal in those days worked for the Newspaper and was the head of
> production so was often taking calls during a contest and solving
> problems at work.
>
> Anyway the phone rang and I answered it.  The voice on the other end
> said, "Is this Howard Blegen", I replied no he is on the radio, hold on
> and I'll get him.  The voice replied, fine, tell him it's the FCC.
>
> Oh might fine....I grabbed Hal and told him that he had a call from the
> FCC.  He thought of course that I was pulling his leg.  He answered the
> phone tho, this is Hal.
>
> The FCC guy as Hal related a little bit later said, "Are you on the air,
> and Hal replied you bet we are on 14.085."
> The monitoring guy said hold on a sec, and evidently moved his dial up.
> FCC dude sez oh yeah you are real strong on 14.085.  About 47 dB over
> S9, only problem is that you are also on 13.990 and that just happens to
> be Air Force Transcon MARS and you are covering most of there stations
> as you are S9 down there.
>
> Hal had me double check on another received with no antenna and sure
> enough....
>
> FCC dude was understanding and sent Hal a little letter,  Hal had the
> pleasure of explaining that his jim dandy FSKing of the fine Kenwood
> Twins using the standard Irf Hoff 3-12 pF trimmer and diode in the
> Cathode pin of the VFO tube was a little suspect using this radio.  The
> amp didn't help as it was broad as a barn as well.
>
> Hal took the fine Kenwoods to the next Hamfest in Puyallup, after having
> removed the FSK circuit.  They went down the river.
>
> The letter back to the FCC was brief.  Disposed of lousy radios and
> bought a Yaesu.  Thus Hal came into the modern world (sort of).  Yaesu
> FT[-757 was next.
>
>
>
> W0MU Mike Fatchett wrote:
>> I also recently learned that you can set the receive freq to 915hz so you
>> don't have to listen to that very high pitch at 2125.  Just tell MMTTY 
>> you
>> are running 915 and everything works great.
>>
>>
>> "A slip of the foot you may soon recover, but a slip of the tongue you 
>> may
>> never get over." Ben Franklin
>> -----Original Message-----
>> From: rtty-bounces at contesting.com [mailto:rtty-bounces at contesting.com] On
>> Behalf Of Bob
>> Sent: Wednesday, March 04, 2009 7:26 PM
>> To: RTTY Reflector
>> Subject: Re: [RTTY] Calibration Check with W1AW RTTY Bulletin
>>
>> Thanks to Dick AA5VU and Richard VE3IAY for taking the time to answer my
>> question.  I was thinking there was something magical about a 2125 Hz 
>> tone
>> but that just sets the location of the Mark Freq in relation to your rigs
>> freq readout.  I guess that's why it doesn't really matter if you use LSB 
>> or
>> USB just as long as you set the mark freq and then shift in the right
>> direction.  I guess that's why there is a reverse button in most of the 
>> AFSK
>> RTTY SW.
>>
>> So if I want to set up a QSO on RTTY I just need to tell the other 
>> station
>> what freq my Mark will be on and let them do the addition or subtraction
>> depending of their SW or rig.
>>
>> Thanks again
>>
>> Bob
>> K4QHH
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