The topic got started again recently when Goran, S55OO asked:
I wonder if anybody had made some tests between all popular hardware and
software, and how to best set them up.
Grant, W4OJC replied with his opinions in this informative email:
I use WriteLog/Rttyrite in several combinations. I have done side by side comparisons using a Hal ST8000 modem as the standard.
Number 1): RITTY by K6STI ( k6stil@n2.net ) is the best rtty program. It copies 10 to 15% more than the Hal ST8000 in weak signal conditions, and through QRM. It requires an ISA slot and works 100% with a plain SB16 sound card which is about 20USD. Ritty is very easy to use. The set up seldom requires adjustment. Under weak signal conditions, i.e., no S-meter movement and barely audible or not audible audio, it will copy 40 to 50%...enough to get serial numbers, calls, etc. Signals are frequently seen in the DSP waterfall, that are barely, or not audible. It is a state of the art DSP program for $100 that can be used in Writelog as a modem, or for rag chew in a DOS window. RITTY works in WIN98SE, I do not know about RITTY's operation in ME or W2K.
Number 2): Hal ST8000 modem (hardware). Has built in scope with mark space individual adjustments. Has selectable FM or AM hard limiting in QRM and QSB conditions. As this hardware is my standard, I rate it second behind RITTY, because of 10 to 15% less copy than RITTY. The ST8000 is a solid and stable design using the best hardware technology that was known 15 years ago. Under weak signal conditions the copy is 15 to 25%, usually not enough to be intelligible.
Number 3): RittyRite. Using it side by side with the ST8000, copy is about 15 to 20% less than the 8000, more notably in weak signal and QRM conditions. Not usable under weak signal conditions.
Number 4): MMTTY. Under strong, steady, and clear signal conditions, it is equal to the ST8000--but these conditions are seldom found. In QRM, QSB and weak signal conditions, it copies 25% of what the ST8000 copies. By tweaking the settings, i.e., increasing the number of taps to 96 on LPF and narrowing the BPF to 1200hz or less, there is some 5 to 10% improvement in its copy. Not usable under weak signal conditions.
Number 5) PK232 (hardware) with internal DSP (latest version from Timewave). The internal DSP is an improvement, however, with the internal DSP the PK232 copies 10 to 30% less than MMTTY. Not usable under weak signal conditions.
Not available to work with WriteLog at this time is MixW, by UT2UZ. MixW uses any SoundBlaster card and copies approximately slightly better than the ST8000. I am saying approximately as I have been using it only one month now, but have a good feel for it. There is a trial version available until October 1, 2001, at http://tav.kiev.ua/~nick/mixw2/ This too, is a state of the art DSP program. It is $50. Under weak signal conditions, the DSP waterfall, frequently *depicts* signals not audible. Weak signal copy is approximately 35 to 45%.
To make these comparisons I use the audio from the two receivers in the FT1000D to feed each program independently. I have swapped the audio between receivers and have varied the equal performance of the receivers with a IFR1000 calibrated signal generator. The antenna at the present time is a 20 meter 3 element wide-spaced monobander at 25 m. My favorite combination at this time, is to start WriteLog and run 2 Rttyrite screens...one using the ST8000 as a "dumb terminal," and the second Rttyrite screen with RITTY selected as the terminal--an easy install. If one rtty screen misses a serial number, etc., the other one usually has it. As always.... individuals' "mileage," performance, "print percentage," may vary. - Grant, W4OJC
Then John, WA9ALS jumped in:
Boy, that question will generate some traffic, eh? No data to show you Goran,
but I'll give you my experience, and I'll bet it's not too far off the general consensus...
We'll see:
RITTY/K6STI might be the very best modem, although I've never used an ST-8000 ($). 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 is available with the soundcard within the Writelog program,
and 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 or like DOS computer?
3. How much can you spend ?
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.
Don, AA5AU added:
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)
PK-232MBX
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 PK-232MBX as main receive and transmit on the other computer/ radio.
Why do I still use a PK232 if I rate it 4th out the 5 I've used? 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. 73, Don AA5AU
In an earlier email about the KAM, Don had said:
I use a PK-232 and soundcard on one computer/radio, and a DXP-38 and soundcard on the other computer/radio. It's an awesome combination. With the power of WriteLOg you can have as many as 4 RTTY windows at the same time, but that takes up too much on a single monitor. However if you have two monitors connected to your computer, you can run WriteLog and have dual monitors (Win98 or later required for dual monitors). You can also if you like, transmit from any of the RTTY windows if you parallel all the FSK outputs together into your radio (assuming that you are using FSK
Bob, NT1V stuck in his two cents by adding that he has two PK-232's both of which had been modified to improve narrow shift capabilities - see www.qsl.net/k0bx for the following articles: "Aligning the PK-232(MBX) for 170 Hz Shift" and "IMPROVED PK-232 THRESHOLD DETECTOR".
I feed my ST-8000 into one of the PK-232's as an external modem, and therefore can
use more than two dozen RTTY software programs with the combination. The ST-8000
provides tunable filters, selectable limiting, and other features ahead of the PK-232,
and the software
thinks it is talking simply to a PK-232.
(see also "How to Use the ST-8000 in Front of
Your PK-232, By Bob Boyd - W1VXV", on the K0BX site).
One of the PK-232s is an old unit and the other is the latest TimeWave version with
DSP. Don't sell them short; with the mods applied they work a lot better than
when they left the factory!
Incidentally, I still rank the ST-8000 as best for both DXing and contesting. I do not recall the last time that I needed to request fills. I do intend however to add another window on the screen, and start to use MixW with the soundcard in dual-receive mode. Then I want to make some side-by-side comparisons.
And from Jerry, W4UK:
A major feature of the PK-232 that Don does not mention is the ability to easily interface an external "front end" to it. It is easy to bypass the PK-232's filters (that were never optimum for 170 Hz RTTY anyway) and replace it with more optimum circuits to convert the tones into 5-bit TTL level signals. I have used an old highly tuned ST-6 with near optimum post-detection 45 baud low-pass filtering for years in this configuration by tapping in just before the ST-6's loop keying circuit and converting it to TTL. It's copy far surpasses the early sound card demodulators.
I have more recently used a second PC running a copy of MMTTY, directing it's output to a COM port on that second PC, then translating that port's voltage level to TTL and patching it over to the PK-232, which is feeding WL on the first PC. In the above configuration, I get to continue using the PK-232 as FSK keyer and CW keyer while still taking advantage of possibly better external demodulators. The external demod input is on the back of the PK-232 - you have to rewire jumpers inside the case to enable it. The manual covers it well.
I am rebuilding my station now, integrating my new IC-756PRO into it, and considered tossing the PK-232s, but decided to keep them in the rebuild because they do such a good job of FSK and CW. I may drop the ST-6, though - I have to compare it carefully to MMTTY running on that second PC before I am sure. I use these PK-232's exclusively for 45 baud RTTY, and those needing other modes would also need to provide for switching the original PK232 filters/demodulator back in for those modes. This can be done with an external switch. - Jerry, W4UK
And from John - VK4CEJ:
For what its worth, some months ago, I ran Zakanaka (which uses the mmtty engine - on a soundcard), and HyperTerminal to control my PK-232 at the same time. With both the 232 and soundcard receiving the one rtty signal, the 232 was more than accurate every time.... and this was in it's 'out of box' configuration. Since then I have spent considerable time making modifications to the 232 so that it is now 'tuned' for 170hz shift, and it now receives rtty better than ever.