Category: Electronics

BITX40 PTT Enhancement for Digital or CW

The BITX40 PTT is a simple circuit: A switch grounds out the PTT Relay and the transceiver goes into transmit. As a stripped down SSB radio, this works fine and is simple and uses few parts. Why modify it? The challenge is that the PTT circuit is not solid state. The PTT circuit is just …

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MultiBand BITX40 Conversion

MultiBand BITX40 Introduction In Several Older Posts I’ve touched on ways that you can make a multiband BITX40 radio. While those methods worked, they were experimental. The Dual Band option will likely work fine, but I found it overly complicated for the purpose. In this post, I’m going to show you a way that you can …

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Building an RF Probe for Fun and Measurements

Who needs an RF probe? Among the many things I’ve learned about ham radio, one of them is that you need test equipment. You can do a lot with a standard Digital Volt Meter, but one thing you can’t do is look at an RF signal in an HF radio. For that, you need an …

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QRP Labs VFO Review [Spoiler: we love it!]

I’ve had the QRP Labs VFO for many many months now and it’s about time I got around to actually writing a review of it. When I originally purchased my BITX40, it did not come with a digital VFO. With the analog VFO, tuning was an exercise in futility. I had never owned an HF …

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QRP Labs U3S WSPR Transmitter Build and Test

The QRP Labs U3S is a multi-mode transmitter kit. It outputs 200mw of power on any band you have a filter for, and is extendable to up to 6 bands that it can rotate through. It’s only $33 and is incredibly capable. Let’s check it out! I received the U3S in April 2017, but was …

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Catching up with MiscDotGeek: September 2017

It’s been a busy month at Chez Geek. This post involves an improvised lathe, a burrito, Linux, antique cast iron, and a duck. We’ve been working on projects off and on, and have had some family health issues to muddy the waters as well.  Rather than tell a big long story, here’s a few headlines …

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An Inexpensive Digital Multimeter for the Thrifty Ham

When playing with ham radio or any other electronics, it’s pretty obvious that you need a Multimeter (DVM, Meter, whatever you want to call it) and if you’re like me, you’re on a bit of a budget. For me, I wanted to accurately set the bias on the IRF510 PA in my BITX40. This requires …

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20M Inverted V with Lightweight Dipole Center

One of the many joys of being a ham radio operator is building antennas. I’ve covered the L-Match tuner and long wire antenna in the past, and while it’s a great way to get on the air, a resonant antenna is always nice- if you have the room for it. When you’ve only got 5w …

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Converting the BITX40 to 20M

A very hacked BITX40

20m BITX40 conversion IMPORTANT- READ THIS FIRST [UPDATE 11/14/2017]: After even more experimentation, I have concluded that this method works great for the Band Pass Filter, but that the BITX40v3’s PA is not optimized for operation above 40m. It will work on 20m, but at reduced output of only 1 watt. The following information is left …

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The Quest for the Genuine IRF510

The Problem Recently, I had a need to replace the IRF510 PA MOSFET in my BITX40 radio. A malfunction with my VOX PTT circuit caused it to stay keyed down for a very long time while unattended. Oops! With that fixed, it was time to replace the IRF510. The Search I scoured the usual places …

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