Building the PA0RDT Mini-Whip Antenna

The PA0RDT Mini-Whip Antenna is a small and compact active antenna that acts as a full-size antenna for bands ranging from VLF to HF. It’s ideal for cases where you can’t put up a large antenna or are restricted on space. Most of the feedback on the design I found online was quite positive, so I decided I’d get one and try it out for myself.

A few weeks back I bought a Mini-Whip active antenna kit from a seller on eBay. While I could have built it completely myself, I liked the idea of having a neat and tidy antenna on a printed circuit board, so this was great, and I was able to put it together in about half an hour.

PA0RDT kit

PA0RDT kit

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Testing Dipole Antenna and Radio Mod

Not content with just modding my radio today to give it an external antenna socket, I had to go and build an antenna to try it out!

The washing line in the garden seemed like the most obvious place to put it as it’s quite high off the ground. This gave me about 13m to play with for a dipole, with an effective frequency of about 23MHz. Since my current radio doesn’t go as high as that, I instead used the antenna as a halfwave dipole, where it becomes useful at around 11.5MHz. This was quite a rough-and-ready experiment so I didn’t bother with matching or baluns or anything like that; I just plugged that bad boy in. Continue reading

External Antenna Modification

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I recently ordered a Tecsun PL-600 to go to the next step of shortwave listening. It has lots of cool features that my current receiver – a SilverCrest Digital World Receiver I got in Lidl for about €15 some years ago – doesn’t have. So, I took this as an opportunity to improve the SilverCrest without fear of causing permanent damage to it. For years I’ve been using a simple random wire clipped to the whip antenna on the receiver to listen to stations from around the world. The method has served me well so far, but I wanted to be able to connect a proper antenna fed with a coaxial cable. I decided to add an RF socket to the SilverCrest.

This modification can be applied to any similar portable radio: all we’re doing is connecting the centre conductor of the RF socket to the whip antenna, and the outer shield connector to the battery ground. The whole process probably won’t take more than 30 minutes.

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Constructing an ADS-B Collinear Antenna

Antenna feedline, adapter, USB receiver and laptop

I haven’t posted here in about a year and a half, which is shameful! But, my last post was about low-cost SDR, and since then I’ve ventured into it. In this post I want to describe how to build a collinear antenna, which can be used for receiving ADS-B signals on 1090MHz from aircraft. I use a NooElec R820T tuner dongle on my laptop as my radio receiver (I’ll write up more about this later), and as I love quite close to an airport, it’s ideal for capturing signals from airlines. Continue reading