PC and Rig Interfacing
QSO Parties are about fun, but let’s not forget they are also contests.
Doing your best is part of the fun. One way to improve your QSO performance is by automating some aspects of your station.
One clear way to make things more convenient is by connecting your logging program to your rig. Possible advantages include:
- Logging software changes bands in sync with your radio band choice
- Current frequency recorded in logging program
- CW dialogs can be programmed to send repeatative information like “CQ CQ DE…”
- Digital modes such as PSK31 and RTTY are made available via applications including MixW and a good sound card interface
There are three things we need to consider connecting between the computer and the rig:
- CW Keying Line
- Rig’s Serial Interface if available
- Audio in and out.
Products and designs exist for each of these needs. There are also products that to it all. The do it all products cost quite a bit. The individual product range in price.
When outfitting your particular rig to your particular circumstances keep in mind that the all in one solution, even while higher in cost, might actually be less cost than a piece by piece approach.
Sound-card Interface
Settle for nothing less than complete DC isolation between the rig’s audio ports and your computer’s sound-card jacks. Yes, there are some folks who get away with connecting things with straight cables, but transformers are just too cheap and good designs available to not consider the advantages of isolation.
The Line-Out port from the computer to your rig’s audio input is the simpler of the two interfaces. Modern rigs provide a connection on the back for near line level input. Still you need to pay careful attention to the output level of the PC. Attenuation may need to be designed into the interface.
When inserting the PC audio into your rig’s microphone input, you need to be very careful to attenuate the signal. You might damage the rig if you don’t.
If you are lucky your PC has a line-in port. Like the Line-out it is a stereo port. You can take the speaker out from your rig or, better yet, the constant level out available on the accessory ports on the rear of the rig.
If you do not have a line-in jack you may have a microphone input. This is not stereo even though it has the tip-ring-sleeve plug. Instead this is a single audio channel and a voltage suitible to power microphones. You need to be very careful what you do here as putting the signal in the wrong pin may destroy your input.
CW Interface
A popular way to have a PC key a transmitter uses the DTR or similar line on the PC’s serial port. This has worked quite well for ten plus years. However, today’s PCs have a very real issue with real-time control over their serial port. This yields very sluggish and sloppy CW in PCs even when they are not doing anything else. This is of course if your PC even has a serial port available. Most new PCs don’t have a serial port.
The good news for both problems is the use of external keyers with the WinKey chip installed. In this configuration the WinKey chip does the real-time control of the transmitter. Since this is all the WinKey chip does it sends perfect CW. All the PC needs to do is keep the buffer of characters to send flowing to the WinKey. Interruptions in the PC may stop the flow for a moment, but it will resume quick enought to keep the WinKey buffer full.
I have done both methods and can easily suggest WinKey is the only solution worth considering for PC control over the keyer line of your CW transmitter.
Serial Control
Do you forget to change bands on your logging software while searching for QSOs on your radio? Do you then log a bunch of QSOs with the wrong band only to have to go back and change them one by one to ensure your dupe checking works?
Purchase the adapter for your radio to a serial port and this will no longer be an issue. The Computer Aided Transciever (CAT) port sends band change, frequency and other details to your serial port. Your logging software quite likely has the ability to accept this stream of data and set parameters accordingly.
If you had to pick just one of the three time savers during contesting this just might be it.
In another installment we will list available adapters and see where the best value might be found.
