Wednesday, February 27, 2008

The Sound of Silence

Last November we drove down to Disneyland in my wife's van, and I wired up a VHF/UHF rig and mag mount for the trip. Ever since the phone systems failed due to overloading during the relatively minor October 2007 Alum Rock quake I've been nervous about relying on cellphones in emergencies. I spent some time researching repeaters along the route, and more time programming everything into the radio.

All for naught, apparently. During the trip I was struck by the almost complete lack of traffic on every repeater I tuned in. It wasn't a problem with my equipment; there just wasn't anyone on the air. Even in the densely populated Los Angeles area, the entire twelve hour trip was mostly a never-ending chain of silence. The most traffic I heard was on linked systems such as the Cactus Intertie and the WinSystem, but that's to be expected because they have dozens of connected repeaters and all it takes is one person talking somewhere on the system to light them all up.

On my base and mobile rigs I have a lot of local repeaters programmed, ready to go. And yet at any given time; nobody's talking. Pick up the mic, announce "W6DTW monitoring".... and listen to silence. Reminds me of the This Week In Amateur Radio "Random Access Thought" segment by Bill N2FNH about a repeater that died when a spider crawled across a circuit board; shorted himself across a resistor; killed the repeater...and nobody noticed. And yet; try asking your local frequency coordination council for a frequency pair and you'll get told "there's nothing available". The howling wind of silent FM static is blowing through most of our local repeaters just as it was through the repeaters I tuned into on the trip to Southern California. So how is it that all of the frequencies are spoken for..?

Things are not much better down in the HF bands, or perhaps I should say not much better in the legal HF bands. Given that we're currently coming out of a low point in the 11-year sunspot cycle you might be tempted to allow that the amount of traffic will be low. Especially in the higher frequency bands like 10 meters, where popular wisdom says there's little propagation during the day and certainly none at night. So the 40 and 20 meters bands have some traffic (mostly contesting), 17 meters opens up around noon for a while, and we're starting to hear folks on 15 meters. But for the most part; few stations are on the air and silence above 21.5 MHz is the rule.

So then why is it that on any given weekend day, if you listen above 27.405 MHz into what's been termed the Freeband, you'll very likely hear a lot of traffic? I hear strong stations coming in from around the Western US and Mexico. Is there something odd about propagation that creates a difference between 27.915 MHz (aka the freeband "Redneck Skip Calling Frequency") and 28.400 MHz (aka the amateur "10 Meter Calling Frequency") so that one is active and the other not? Surely the Freebanders don't have some kind of secret technical prowess that allows them to punch through where amateurs cannot? The reality is likely that amateurs simply don't believe that there's good propagation without sunspots, so they don't tune in and "no propagation" becomes a self-fulfilling prophecy.

I find it amazing that while the great swaths of spectrum which amateurs can legally use sit idle; another group of people who are sometimes called "pirates" (agree or disagree with the term as you wish) are happily making use of frequencies which are right next to a band that amateurs will effectively ignore for a good 25%-40% of every sunspot cycle. Yes, Freebanders are operating illegally according to FCC regulations. No, I'm not a Freebander. However; I do have a sense of respect for them. They are (from what I can see) more enthusiastic and aggressive about pursuing the hands-on technical aspects of radio than many hams. They're out there modifying radio equipment on their own---which they have to do because there's no legal way to buy freeband radios. They're not sitting around waiting for sunspots to come back so they can get good propagation; they get on the air and take what the sun gives them on that day.

That's real radio.

Monday, February 11, 2008

Expensive Desktop Mic Get Pwned By $12 VOIP Headset

A while back I purchased an entire amateur radio set from a ham who was getting out of the hobby. A rare occurrence, mind you. I really only wanted the radio (a Yaesu FT-1000D) but the guy sold me everything except the feedlines and antennas for less than I'd expected to pay for the radio. Everything worked as expected. In the plethora of boxes I lugged home were a lot of accessories; among them a West Mountain Radio RigBlaster Pro.

The RigBlaster sat in storage for almost a year, until recently when I watched K7AGE on YouTube talking about his homebrew Bluetooth headset interface. One of the accessories which came with the FT-1000D was a Yaesu MD-100A8X desk mic. I've frankly been less than pleased with performance of that mic; it's very sensitive to any change in sound level due to distance from my mouth which means that keeping the FT-1000D's ALC from kicking requires that I constantly ride the PA drive control--and that's tough to do when I'm focused on maintaining a constant mouth-to-mic distance. So I started thinking about getting a headset. Of course, you can spend a ton of money on a "good" headset; e.g. Heil Sound is the name in radio mics and headgear and their stuff starts over $100 and goes up from there. Being the cheapskate I am I decided to experiment with a $12 General Electric VOIP headset I got from Target to do Skype while I was traveling through Asia in 2006.

Interface to Yaesu was a snap using the RigBlaster. As with most amateur radio accessory companies, West Mountain Radio's website and manuals are poorly written but I was able to decipher them enough to set the jumpers properly for the Yaesu. Most computer headsets are have electret voice elements which require a 5 VDC bias on the ring terminal; the RigBlaster can provide bias on the MIC2 jack which also happens to be the perfect size for a PC headset plug. I didn't bother to route any of the receive audio paths; for now I just have the receive side plugged into the headphone jack. I have the MD-100 plugged into the RigBlaster--just in case--but its primary function now is to act as a PTT switch.

The results were impressive. I checked in to the 75M late night net and got an unsolicited report of "great sounding audio" from W6EZV. A flattering report, considering that the 75M late night guys are used to hearing perfectly processed and equalized audio from people like W6OBB aka Art Bell. I'm now able to operate with both hands free, and the headphone has an added benefit of making sure the receive audio is not bothering my family after they've gone to bed. My audio settings are a lot more consistent and don't require constant fussing with the PA drive and speech processor levels. Best of all I'm no longer inclined to go out and spent hundreds of dollars to get a high-end Heil headset. I'm now curious to find out if my successful experiment is unique to this particular VOIP headset or if I can get the same results with other brands.