Author: W3AXL

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Uniden BCD996P2 Internal GPS Mod

Like many hams, I have a scanner installed in my vehicle along with my radios. It’s great for keeping tabs on what’s going on around the area. The newer models of scanner from the major players (Uniden, Whistler, etc) typically have GPS capabilities to lock/unlock scanning banks depending on your location. This is super convenient, especially when you travel across states frequently as I do. I own a BCD996P2 that I picked up secondhand from a friend a few years ago. It came with the standard Uniden “puck” GPS receiver, which plugs into the scanner’s rear DB9 port and includes

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DIY Sat Rig: Amplifier Design & Testing

Apologies for such a long gap between posts. I meant to keep up with the sat rig project more closely but work and travel are doing a good job of getting in the way. Turns out, it’s not as easy as I thought to work on a large personal project while travelling all over the country for work. In this episode of the DIY Sat Rig saga, we’re playing with real power. Well, 10 watts at least. The boards for the first revision of my amplifier design came in, and I just couldn’t wait to start finding out if my

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DIY Full-Duplex? It’s easier than you think!

Well, it’s been a while. Between finishing out my EE degree, moving my life three states away, and setting up at a new job, I’ve barely had time to do anything ham related, let alone some DIY designs. Now that it’s been a few months, I’ve settled in and started busting out the Kicad skills and lab tools to get the wheels turning on a new and exciting long-term project here in the shack. After weeks of tinkering, tuning, and troubleshooting, I’m proud to reveal the pre-alpha version of what I’ve been toiling away at during my absence from the

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Osmo-FL2K – The RTL-SDR’s Other Half

An interesting new development has sprung out of the wonderful Osmocom project: a low-cost, wide bandwidth SDR transmitter that works with GNURadio. How low cost? How about $10? This is all possible thanks to the wonderful work of Steve Markgraf, an Osmocomm developer who found that when properly coerced, a cheap USB3.0 to VGA adapter will output raw samples straight from its RGB output lines. While the base sample rate of the dongle, using the FL2000dx VGA chip, has a normal max frequency bandwidth of 150MHz, it was found that since the output is essentially unfiltered valid signals can be

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Panatap Update: Living in the Real World

Hi all! Just a quick update in regards to the responses I’ve received for my Panatap board. First off, thanks to everyone who’s given me positive feedback for my design. I really appreciate everyone who has found my design useful, and I hope that future projects that I’m working on will be just as helpful. One thing I wanted to address is a question that several people have commented or emailed me about: component values. Specifically the values of the capacitors and inductors used in the low pass filter. The values I specified in the schematic and in the board

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DIY / Panatap

W3AXL Panatap: We Are Go for Liftoff!

Hello again everyone! I apologize for the lack of updates. School, as it often does, got in the way once again and I haven’t made real progress on any of my own projects in just under a month now. Luckily that all changed recently. With nothing better to do on a Saturday night, I set forth a goal of completing the new revision of the redesigned G4HUP panadapter (what I’m now calling the W3AXL Panatap) and getting it installed in my FT-450D. This proved to be both easier and more difficult than I thought. Details inside!

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Panadapter Board Update: Whoops!

Hi again everyone! I received a surprising amount of emails regarding the panadapter boards that I had made. Well, I’m here to tell you that like all good things, it takes time to get things right. Some of you who know far more about amplifier design should look back at the schematics I posted in the last update. You’ll notice something ever-so-slightly out of place. Yep, that capacitor is supposed to be below the resistor, connected directly to the FET. Unfortunately while it seems like a simple error it actually managed to throw off the bias of the amplifier quite

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DIY / HF

Panadapter on a budget! Revival of the G4HUP PAT Board.

NOTE: Check the latest blog post for an update on the below information! I recently acquired a shiny new Yaesu FT-450D. I knew almost immediately that I wanted to use one of my many RTL-SDR dongles to set up a pandapter. As luck would have it, all the hard work was done for me by Dave Powis, G4HUP. He had designed a compact, high-impedance IF tap for direct connection to any SDR. Unfortunately, with the passing of Dave came the end to all shipments of the PAT board, leaving me high and dry in the search for a cheap way

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Updates & Wiki

Hi all! It’s been a while since my last post. School and life has kept me plenty busy, but I’ve been trying to get a few new blog posts up. It’s hard to dedicate enough time to get quality content up – and that’s why I launched the W3AXL wiki earlier this year. I’ve learned quite a bit through my repairs and modifications of Motorola equipment, and instead of talking several hours writing a blog post, I’ve opted to instead update this wiki with information all about various Moto products. Visit the wiki here! You’ll be seeing new pages and

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Antennas / DIY

Building a No-drill Antenna Rack for Your Car

There comes a time in some hams’ lives when they’re faced with a dilemma. They can’t drill their car, the mag mounts are getting old very fast, and trunk lip mounts just won’t cut it. The misguided of the lot go towards glass-mount or fender-mount antennas, and settle for poor performance and high losses. The more adventurous, well, we get creative. So if you’re like me and you want to mount a whole bunch of antennas to your car but don’t want to drill the roof, this is the story you want to read.

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