[RTTY] RTTY Tx options - advice requested

[David G3YYD]

Dave

You are using a K3. I tried to overdrive my K3 by turning all the "knobs to
the right" on the K3 and the PC sound card. I then listened on my other K3
and I could not hear any audio harmonics at all on the transmitted signal.
This was with the 2Tone AFSK filter off. I always use 1275/1445Hz tone pair.

Conclusion just use the tone pair you want to with the K3. But better not to
have all the knobs to the right.

By the way I also always use VOX with the delay turned down to the minimum.
This saves having to fiddle around with a PTT line.

73 David G3YYD

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Dave
Hachadorian
Sent: 01 December 2014 15:54
To: reflector RTTY
Subject: [RTTY] RTTY Tx options - advice requested

We've got the 10 Meter RTTY Contest coming up this weekend, and I'm trying
to figure out the best way to do the RTTY Tx function. 
I think the combination of switching to N1MM LoggerPlus, and switching to
2Tone as primary decoder have raised some issues. 
Here are some available options as I see them:

I could do AFSK, but I've grown accustomed to hearing the
915/1085 Hz tone pair, and apparently that's dangerous because the harmonics
fall into the 2.7 KHz passband of the SSB filter. 
Can I get away with that tone pair?  I'm using a K3 radio,

I love 2Tone for receiving, but apparently its FSK Tx is subject to timing
jitter if the computer is not a quad-core powerhouse. 
My computer is pretty good, but not THAT good.

I have the parts lying around for G3YYD's deluxe pseudo-FSK circuit, with
the comparator IC.  I could jump back onto that project and probably get it
done in time for the weekend.

The FSKit sounds like a good option, but apparently the circuit boards and
programmed controllers are no longer available.  If someone has one to sell,
I'd like to hear from you.

I could use MMTTY for Tx.  Apparently its FSK is not subject to timing
jitter?  I could then use 2Tone in a separate Rx-only window, but then I
wouldn't see my transmitted text in that window, which is unnerving.  I
could move my eyeballs between the two windows for Tx/Rx, but that is
suboptimal.  Overall, this sounds like the most certain approach though.  Is
MMTTY FSK timing solid, even on a moderate-speed computer?  I'm using a real
PCI serial port card.

Is there an inexpensive hardware modem that I could use for RTTY Tx-only?

I would appreciate comments on the above options.  If anyone has a better
idea, please let us know.

Many thanks.

Dave Hachadorian, K6LL
Yuma, AZ



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