A little while ago, I got a hankering to work on a SSB transceiver. It’s something that I’ve never homebrewed before, and it seemed it like it might be fun to tackle. The BITX20 seemed like an obvious choice, and W7ZOI recently published an improved bidirectional amp which would be nice to try in the… Read More QRP SSB Transceiver in Progress
While I was away on my honeymoon, I noticed that the upcoming kit that I’ve been hinting about for months has finally been released. The Four State QRP Group announced availability of the VRX-1 direct conversion receiver. The VRX-1 is a simple 40 meter VXO-tuned receiver (crystal on 7.030 MHz), but it’s not your typical… Read More Introducing the VRX-1
QRP is tons of fun on CW, but it gets a bit rough trying to work other stations on SSB with 5W, especially when you are using antennas that are low to the ground. I had been eyeballing the nice RF MOSFETs from Mitsubishi for a while, and since I got a hankering to get… Read More Homebrew 20 Watt Linear Amp
Well, I’ve pretty much put the finishing touches on my secret QRP project for a well-known QRP club. The beta testers are currently working on building it, and hopefully the club can make an announcement about the kit fairly soon. It’s not a very complicated circuit, but it’s somewhat novel and has a bit of… Read More Back from the Bunker
Last week, I was informed that everyone in our company would be receiving a temporary (but indefinite) 10% reduction in pay. To make matters worse, it looks like we will be taking more mandatory shutdown days in the current quarter; we’ve got five coming up over the next few months. This is also another open-ended… Read More Watch This Space
You can never have enough low frequency decoupling in an audio amplifier with 100 dB voltage gain. You can never have enough voltage regulation on the VXO you are using to feed your diode mixer. Not enough and you get all kinds of nasty low frequency oscillations in the receiver.
As I mentioned in a previous post, I did the calculations to change the AF filter in the Willamette from a low-pass filter with a 3.3 kHz cutoff to a peaked low-pass filter with a cutoff frequency nearer to 1 kHz. I finally got around to implementing the mod last night and got a chance… Read More Willamette AF Filter Mod
I finally got a few days of decent sleep (decent meaning more than 4 hours), so I had a little energy to work on the simple DC transceiver. A few days ago, I got the remainder of the audio chain working. The emitter follower on one of the outputs of the differential mixer was yanked,… Read More Progress is Made
Yes, its a post about another simple, low-performing direct conversion receiver. However, I think that this one is slightly unique. I was inspired to give this a try based on the Flea minimalist transceiver that was introduced on the EMRFD Yahoo group. These little rigs are fun to build in an evening, but just how… Read More Yet Another DC Receiver
Even though a homebrew return loss bridge is a relatively simple piece of gear to build, I’ve never gotten around to building one until now. Which is truly a shame, and something I don’t really have an excuse for, except perhaps laziness. I’m excited to add this essential gear to my stable of test equipment,… Read More Dual Gate MOSFET Investigations – Return Loss