PSK31 for the K2

Don’t recall the status of this post. Somehow I forgot about it several years ago and found it in Drafts recently. Here it is. Reader be warned!

July 2010

Some months ago, I posted the addition of the K8RA paddles to my K2-5373 at the bottom of the K2 page. Not to leave well enough alone, I decided to revisit PSK31 in this new upstairs location. Motivation: I bought a new Apple MacBook Pro, and it was begging me to hook it to the K2.

The bottom line: Audio in/out with the Apple running Snow Leopard (OS-X) was surprisingly easy compared to the PC. Setting up PSK31 with my PC’s was a major hassle, and far more difficult than the Apple.

Hardware Issues

The 13″ MacBook Pro (MBP) has an audio card, but to my dismay its I/O is through a single 1/8″ jack. Instead of being able to use two normal stereo cables from the local Radio Shack, I needed a plug with two rings instead of one; those plugs aren’t so easy to find. RS does have an Apple iPod cable with a click switch and stereo jack (Gigaware microphone and track control, 12-635, about $8). After breaking open the switch assembly, and adding a plug for K2 audio to the MBP and a mic connector for the K2, the cable was ready.

First problem: The wimpy K2 headphone jack didn’t connect too well, even though I hardly ever use it. I mounted a stereo jack on the back of the K2 and connected it with shielded 2-conductor cable to the product detector output J5. That’s the empty connector near the front-center of the RF board, and it serves as a line-out connection for a constant audio level to the MBP. See photos.

Second problem: After hooking up the mic cable to the K2 and the line-out from the K2, I discovered that beeps and other audio from the MBP were part of the audio. Both were woven together, and I needed a second audio board.

After a query to the Reflector, I had a likely solution: the Griffin iMic USB Audio Interface. (Thanks to Kok Chen, W7AY, among others for the link.) Simple, just plug it in.

iMic Setup

There were no special device drivers, or any special configurations to set for the iMic. When it was plugged in, it showed up immediately in System Preferences | Sound.

Setup Input

Input Setup: Select Input tab, highlight the iMic, provide audio from the K2, set Input slider for something less than max signal. Check with modem program that the signal is adequate. Highlight Internal microphone so other inputs come from it. Done.

Setup Output

Output Setup: Select Output tab, highlight the iMic, set K2 to min power with attached dummy load, turn on ALC display, enable VOX on USB. Set modem program to transmit, adjust slider for ALC indication, set modem to receive again. Highlight Internal Speakers so Mac alerts, music, etc, go there instead of the K2. Done.


Still evaluating whether to go with Fldigi or cocoaModem. So far, I’m using VOX to deal with transmitter switching. It’s simple.

The Office Station December 2010

MacBook Pro and K2

MacBook Pro and K2

It turned out quite nicely. No ground loops, even when I attach the MBP power and plug in the CAT-5 LAN cable. The single screen gets a little crowded, and I’m tempted to run the USB cable into my Mac Pro with its three monitors, a chair-swivel to the right. But then the MBP would need something else to do!

Thoughts on the Mac

Several years ago, fed up with Windows instability and insecurity, I considered Linux once again. After years of waiting, Linux still didn’t meet my computing needs. I bought a Mac Mini to evaluate, hoping that perhaps the Apple would solve my problems. I tried to do everything I could with that little Mac: mail, browsing, calendar, docs with NeoOffice. Fine so far, but some applications were just available on the PC: PhpED, Jasc for photos, Navicat for MySQL. What to do? I bought Parallels and installed a Windows virtual machine, or VM, on top of OS-X; I did a SUSE VM as well, but that’s another story.

The 1-GB Mac Mini was hard-pressed to perform everything quickly when it was running both the VM and OS-X. After I added another GB, it ran okay. Not fast enough for me, but my idea was to use the Mini as a concept test, and the idea proved out. So I bought my current Mac Pro, which has plenty of power and 14-GB RAM. Primarily, it runs Windows 7 and OS-X Snow Leopard. Some sorry Win-apps need XP, so I have a VM for that as well, although I usually have it parked off suspended in space.

Speaking of space, OS-X provides virtual windows called “Spaces.” Go from one screen to the next by keying control-1, control-2, etc. I setup my Mac Pro for 9 separate Spaces; because I have 3 LCD monitors, I have 27 screens available by using just the control and number keys. The icons for open applications can be displayed by pressing Command-Tab, so it’s easy to go to any running app regardless of which screen it’s located on. It was a bit confusing at first, but I settled on this convention: Space 1 (3 screens) has Windows 7 and Chrome, Space 2 has Firefox, Space 3 is Thunderbird, Space 4 Safari, Space 5 iCal and iTunes, Space 6 is eyeTV recorder, Space 7 Win-XP, Space 8 is Mac Word 2011, and finally Space 9 is TurboTax (at the end – I’m trying to avoid it). Meanwhile, I leave Finder (Mac’s file manager), fixed on the left monitor for all Spaces.

All of my VMs have their own IP address, and are set to see each other on my LAN. I can drag and drop files using the Mac Finder to transfer from one to the other. And this is important: the clipboard carries from one VM to the others and to the host (the Mac Pro OS-X). I can copy text in Windows, and paste directly into a Mac application.

The downside is that the Mac hardware is relatively expensive compared to the typical PC. When I consider the time wasted, and all the hassle keeping a PC running right, I think of it as money well spent. The Mac Pro is on 24-7 (with a UPS, just in case), and it goes to “sleep” in the late evening on schedule. I wake it up the the morning, and it’s ready to go.

My Conclusion: The Mac Pro meets all my computing needs. It also provides a bullet-proof platform for Windows, and when Windows crashes, it only takes down the VM, and not the Mac. If I want to do Linux, I can boot its VM in one of my Spaces as well.