brainwagon

I’m saving a link to this page, because I think I may have something misconfigured in my own attempt to use the EMU-0202 sound card for software defined radio. It’s probably not of much use to you if you don’t have that sound card, but… I do, so I am saving this. Genesis G40 SDR […]

Jeff (KE9V) posted an interesting commentary on an article by G4ILO about why he’s not excited by software-defined radio. My comments are mostly directed to G4ILO’s original statements. Before I begin the rant proper though, let me say that if something in ham radio doesn’t appeal to you, you should by no means think that […]

G3XBM posted a link to VE7SL’s nifty LOWFER beacon transmitter, setup to run around 188khz. I’m still fascinated by LF operation under Part 15, and this circuit is just about as simple as you can get. Very neat. Preserved for later consumption.

It’s too late, I should be in bed, but once again I’m reading up on low frequency radio communication, another of those oddball interests you pick up when you read too much. I blame tuning around with the SDR-IQ this evening, where I found that a number of DGPS beacons were easily heard down around […]

Diane, VA3DB passed along this excellent page detailing the inner workings of the Gilbert Cell mixer. I was interested in these primarily because I was trying to understand the inner workings of the NE602/SA602/SA612, and was looking at an LTSpice model of it, and couldn’t understand the way that the various transistors were biased. I […]

Earlier tonight, I noticed that CW traffic on 40m picked way up. You get an interesting view of the band conditions when you can tune 100Khz at a time: Even with my own wimpy antenna, it was hopping pretty good.

Digital Radio Mondiale is a new digital broadcasting standard that is being used on shortwave. Sadly, its one of those annoying standards that relies on all sorts of patented technology, which makes experimentation really difficult and annoying. But I heard that Sackville Canada echoed Radio Chinas DRM broadcasts here to the U.S. for an hour […]

Well, I got a new gadget in the mail today: an SDR-IQ from rfspace.com. It’s a cute little gadget: a general purpose receiver that can deliver the quadrature signals for any 192Khz of the spectrum anywhere from 100Hz (yes, Hz) to 30Mhz. It is a small black box, with only three connectors: a USB, a […]

Over on NT7S’s Ripples in the Ether blog, he presents a link to a project by Joachim, DL1GSJ, a very nifty little SDR designed to operate near the 30m QRSS watering hole frequncy. It uses pair of subharmonic mixers, whose operation I admit I don’t completely understand, but I’m bookmarking the circuit for later consumption. […]

While scanning QRP-L today, I found an interesting link to a project which gave some details about a little WWV receiver that can serve as a frequency standard.   I haven’t had the time to work out how it all works, but it looks reasonably straightforward: Here’s the original schematic from Chuck Adams, K7QO: Nick, WA5BDU […]

I hadn’t worked SAUDISAT 1C (aka Saudi Oscar 50, or SO-50) in quite some time. My recollection was that it was a trickier satellite to work than AO-51, and this pass proved that my recollections were correct. I had significant problems with deep fades. Still, I managed to exchange calls with WD9EWK, K0KU, and N7EDK. […]

I was driving around a bit yesterday (I needed a new hand nibbling tool to punch some holes in a project box, and wanted to get out of the house anyway, so a jaunt over to Harbor Freight seemed like a good way to kill two birds with one stone) so I did what I […]

This morning I got another chance at HO-68, the newest Chinese amateur satellite that was operating in FM mode. I wasn’t sure what the problem was: I had the PL tone setup right and the signals seemed strong enough. On this pass, I fought to try to find a slot to transmit, and finally at […]

I was surfing around the web today looking for an LTSpice model for the NE602, and came across the Elmer 101 FAQ, which is basically an explanatory supplement for the Small Wonder Labs SW40. I haven’t read this carefully yet, but it looks awesome, including much discussion of how the various circuits were designed and […]

As I was chatting on the QRP Echolink conference tonight, the subject of code practice oscillators came up.   I think it was Bob, AD7BP who first mentioned the  NT7S Code Practice Oscillator which I hadn’t seen before, but seemed like a very simple and easy to assemble circuit.  We also discussed the fact that […]