John has made some excellent observations. I think
many of us "field" test these modems all the time during
RTTY contests. I doubt there is any real true test that
can be performed than can differentiate which one or ones
are better except in extended actual use in contests or
everyday RTTY work (mainly DX'ing).
Every condition is going to be different. Several of us
use or have used more than one type of demodulator. If I
had to absolutely rate the ones I've used, I would have to
rate them like this:
MMTTY (sound card)
DXP38
WriteLog's RTTY Receiver (sound card)
PK232MBX
KAM
I have never used RITTY and have used a PCI-3000 on a limited
basis. I retired my KAM. I've switched from WriteLog's RTTY
Receiver to MMTTY on my 2nd RTTY screen. I use my DXP-38 as
the main receive and transmit on one computer/radio and I use
my PK232MBX as main receive and transmit on the other computer/
radio.
Why do I still use a PK232 if I rate is 4th out the 5 I've use?
I use it as the main FSK generator on one of my radios. If I
had a second DXP38, I would retire the PK232, but for now it's
OK on receive. Since I run MMTTY to back up the receive of
my PK232 on one radio and the DXP38 on the other radio, I am
not worried about receive. If one device misses print, the
other usually copies under most conditions.
I used to think that it really didn't matter what TNC you used
in contesting because the exchanges are short and normally
signals are decent. Since I've been using dual receive on each
radio, I can tell you have it does matter. If you have only
one "TNC" on your radio, it probably needs to be the best you
can possibly get or else you are going to spend more time on
repeats, get a lot of missed calls, etc. resulting in less QSO's
or miss that rare DX stations coming back to you while DX'ing.
A dual receive configuration is probably the best way to ensure
that you receive the info the first time without a hit. I have
actually seen the PK232 copy when MMTTY didn't. For the most
part, the PK232 will copy most contest calls and reports. But
on the occasions it does not, MMTTY nearly always picks up what's
missed.
In my experience, MMTTY and the DXP38 are nearly equal. But I
rated MMTTY better because more often than not, it will copy
some things the DXP38 doesn't. And of course, there are times
the DXP38 will copy what MMTTY misses. They are nearly equal.
PK232 and KAM owners should not fret. They are good TNC's. An
example can be made of 3 local RTTY operators in my area that
are all now on the RTTY Honor Roll. Mike, W5ZPA, did it with a
KAM. Randy, WX5L, also did it with a KAM. And Wondy, K5KR,
did it with a PK232 in a very noisy location. I have won many
RTTY contests using the PK232 and KAM. Don't throw them away
because they can be used with WriteLog and a sound card in a dual
receive configuration that outperforms any single TNC or sound
card program.
That's the real ticket.
73, Don AA5AU
-----Original Message-----
From: WA9ALS - John [mailto:wa9als@starband.net]
Sent: Thursday, September 13, 2001 7:18 AM
To: rtty@contesting.com; Goran ANDRIC, S55OO.com
Subject: [RTTY] Re: [WriteLog] rtty RX comparation
> I wonder if anybody make some real tests between all popular HW/SW on the
field?
> What are suggestions for use? ( MMTTY, RITTY, PK232, P38, etc)
> 73,
> Goran ANDRIC, the S55OO.com
Boy, that question will generate some traffic, eh? No data to show you
Goran, but I'll give you my experience, and I'll bet it's not too far off
the general consensus... We'll see:
RITTY/K6STI might be the very best modem, although I've never used an
ST-8000 ($). RITTY is awesome with polar flutter and mutipath. RITTY and
the DXP38 are similar, but RITTY has AFC, VERY useful in contests where
people call off-freq. The DXP tuning meter is difficult to use fast, as in
a contest. (Not such a big deal if you don't mind tuning with your own
oscilloscope and/or you're not contesting). RITTY requires a soundboard to
be SB16 or -very- close...won't work with all. For RITTY, best to have ISA
SoundBlaster 16 card in a DOS computer.
MMTTY seems to be -very- good, maybe similar to RITTY. MMTTY is a Windows
program, and has AFC - thus very popular!
If you use the Rttyrite copy available with the soundcard with the Writelog
program, you can use both channels of the soundcard and so SO2R with one
computer. Rttyrite is pretty darn good too, although a little weaker on
polar and muti at times.
So, it depends on:
1. Computer/soundcard - old or new
2. Do you have/like DOS computer?
3. $?
4. How much you want AFC?
5. Whether you want SO2R?
6. Contesting or casual?
I have a PK-232 also, and I think it is the worst of the bunch. However,
some like them very much, and some have modified them to work even better
than stock. For example, AA5AU uses PK-232s, and you know he does very
well!! ;-) (He also uses a soundcard program (Rttyrite or MMTTY) in
another window with parallel audio, so he has 2 chances of printing the
exchange - the soundcard or the PK-232.
MMTTY has been popular because it is very good, FREE, works with all Windows
soundcards, and has AFC. In the list above, the only possible "weakness" is
not doing SO2R, but you might not be interested in that anyway or could use
an outboard modem for the 2nd radio - some older ones available very cheap.
Good luck, Goran! Hope to print you in CQWWRTTY soon! 73 - John
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