When operating PSK31 I notice that some hams type their text in all uppercase letters ...

Q Larry, WA5MHE, asks, “When operating PSK31 I notice that some hams type their text in all uppercase letters, apparently unaware that the PSK31 code supports upper and lower case. Why do they do this?”

A I suspect that some of these operators may be RTTY veterans. The RTTY code used by most amateurs in the United States is known as ITA No. 2. With the limitations of a
5-bit code, ITA No. 2 can only support a relatively short list of characters. Therefore, RTTY text is in all-uppercase letters, rather than the mix of upper and lower case that we are accustomed to seeing.

There are three problems with sending text in all uppercase:
(1) It is more difficult to read, (2) in the age of the Internet the custom is to interpret all-upper-case words as SHOUTING and (3) uppercase characters in PSK31 take longer to send. Internet savvy hams (the majority of us, these days) are becoming more sensitive to the use of upper and lowercase in digital communication. I think this issue will resolve itself over time.

From QST January 2001
 

I’m attempting to run PSK31 with the DigiPan software, but I can’t seem to get the waterfall display to function properly ...

Q Dennis, AA0A, asks, “I’m attempting to run PSK31 with the DigiPan software, but I can’t seem to get the waterfall display to function properly. I know that audio is getting to the sound card from my transceiver (I can even record the audio using Windows Sound Recorder). Any ideas?”

A This sounds like a display problem of some sort. Are you
using the 256-color display mode? Check your Windows
display properties under SETTINGS—CONTROL PANEL—
DISPLAY. Make sure the SETTINGS are either 256-color or
“High Color.” See Figure 3.

Update: Success! I was running under the lowest color mode—16 colors. I changed the display setting to 256 colors and everything is working!—AA0A

Figure 3—To change your display color settings in Windows, you need to access the DISPLAY window in CONTROL PANEL.

From QST September 2000 
 

In the “PSK31 2000” article in the May 2000 QST ...

Q In the “PSK31 2000” article in the May 2000 QST, there is a single-transistor circuit that is used for transceiver keying via a computer COM port. I’ve seen this circuit used frequently for other switching applications, but some versions add a diode between the base of Q1 and ground. Why is this?

A Radio designer Dave Benson, NN1G, provides the answer: “The diode (D2) between the base of Q1 and ground acts as a ‘shunt diode’ (see Figure 1). The RTS or DTR pins on COM ports can drop to about -10 V in the ‘off’ state, which may be sufficient to get Q1 to go into reverse breakdown. The results could be a rig that is locked in transmit, or otherwise be erratic in its keying characteristics. Adding the shunt diode will prevent this from happening.”

Figure 1—A COM port switching circuit modified with the addition of a shunt diode (D2) between the base of transistor Q1 and ground.

From QST August 2000 

Can you tell me what laptops are known to be compatible with PSK31? ...

Q Can you tell me what laptops are known to be compatible with PSK31?

A If a laptop has a built-in sound card with audio inputs and outputs, it should be useable for PSK31. In practice, however, some laptops have sound systems that refuse to work with the PSK31 software. Others lack the necessary processor muscle.

A few months ago Martin Campbell, KB0HAE, conducted a survey on one of the PSK31 e-mail reflectors to determine which laptops were being used successfully with PSK31. The following list represents the reports of reflector subscribers. It is not a comprehensive list of compatible laptops.

Compaq Armada 1572
Dell 3500 Pentium II 266 laptop with 64 MBytes RAM
Gateway 5150 w/ 300 MHz Celeron
Hitachi MX166
Micron Pentium 166 MHz with 32 MBytes RAM
Mitsuba 486/66 DX
Mitsubishi Amity CN1 (P133/48MB RAM)
NEC Versa 486/33
Toshiba 420 CT
Toshiba Tecra 300CDT
Toshiba Satellite
Toshiba Satellite Pro
Winbook XL 266 MHz Pentium II

From QST December 1999