SPX-100 Portable HF POTA SOTA Antenna — Rated 100W

VIDEO

Introduction

I'm Peter Waters from the Waters and Stanton channel — callsign Golf Three Oscar Julian Victor — and I recently spent some time playing with the Moonraker SPX-100, a compact, budget-friendly portable antenna. At about £49 and small enough to fit in a rucksack, it claims coverage across nine HF bands (80 m through 6 m) and a 100 W rating. I decided to put it through a few practical checks using low-power field kit and share the results.

What the Moonraker SPX-100 Is

The SPX-100 is a telescopic, coil-loaded portable antenna measuring roughly 150 cm when fully extended. It’s aimed squarely at POTA, SOTA and other portable operations where size, weight and ease of setup matter.

Key features

1. Covers nine HF bands: 80 m through 6 m
2. Rated power: 100 W
3. Length: ~150 cm fully extended
4. Base thread: 3/8 in, with supplied adapters for PL259 and BNC (including a right-angle PL259 adapter)
5. Telescopic whip screws onto the top of the coil to bring the antenna to resonance and for fine tuning
6. Band switching via a banana plug and lead arrangement that progressively shorts the coil to go higher in frequency

Build, Connectors and Tuning

The SPX-100 comes with a 3/8" threaded base and a pair of adapters so you can easily convert to PL259 or BNC. The right-angle PL259 adapter is particularly handy if you want to mount the antenna on the back of a transceiver or use a cramped vehicle mount.

Tuning is straightforward: the telescopic whip attached to the top of the coil brings the antenna to resonance and allows fine adjustments, while the banana plug method gives simple band switching without fiddly screw changes.

How I Tested It

I ran two basic, real-world tests: a crude indoor setup and a quick field/camper-van installation using low-power transceivers.

Indoor conservatory test

I set the antenna on a table in my conservatory with a 3 m earth lead from my transceiver (IC-75 in my notes). The antenna was effectively only around 1.5 m tall on the table — not an ideal installation, more of a “see what happens” setup. Running around 5 W, I called CQ on 20 m and checked the Reverse Beacon Network for any signs of life. Despite poor band conditions, I did get a report — one spot from Finland. For a tiny indoor antenna and 5 W, that was encouraging.

Camper-van (portable) test with the Yaesu FTX1 Field

Next I mounted the SPX-100 on the rear door of my camper van and used the Yaesu FTX1 Field (charged up overnight) running 6 W. The FTX1’s healthy battery made it easy to play around with several bands and check VSWR with my Zoom antenna analyser.

VSWR and On-Air Performance

I was pleasantly surprised by the VSWR numbers across several bands — much better than I expected for a compact, coil-loaded whip:

1. 80 m: very good (surprising for a compact portable)
2. 40 m: very impressed — excellent match
3. 20 m: around 1.2:1
4. 15 m: around 1.2:1
5. 10 m: equally good
6. 6 m and the WARC bands: similar to the above — all usable

On-air results mirrored those measurements. With just one CQ on a mediocre band I was picked up via the Reverse Beacon Network when running 6 W from the van — again, considering antenna height and power, quite encouraging.

Who Is This Antenna For?

The SPX-100 is aimed at hams who want a compact, inexpensive multi-band solution for portable work. It’s particularly attractive for:

1. POTA and SOTA operators who need a lightweight, packable antenna
2. Hams who operate from a vehicle while stationary (not really for driving mobile)
3. Beginners who want a low-cost way to experiment with multiple HF bands

While you could fit it to a car, I wouldn't recommend using it as a mobile antenna while driving — it’s intended for portable/temporary installations. Its 3/8" thread plus the provided adapters make it easy to mount on many common tripods, magnet bases, or even on the rear of a transceiver using the right-angle PL259 adapter.

Quick Specs

1. Model: Moonraker SPX-100
2. Coverage: 80 m — 6 m (9 bands)
3. Rated power: 100 W
4. Fully extended length: ~150 cm
5. Base thread: 3/8 in (adapters for PL259/BNC included)
6. Band switching: banana plug shorting arrangement
7. Typical price at the time of testing: ~£49

Final Thoughts

For a sub-£50 antenna, the SPX-100 performed surprisingly well. The VSWR readings across multiple bands were impressive for such a compact, coil-loaded design, and the on-air results with low-power field radios were encouraging. It’s not a magic bullet — you’ll still get better performance from a full-sized antenna — but for portable ops where size, weight and simplicity matter, this is a very usable and affordable option.

I plan to share more about the Yaesu FTX1 Field in future write-ups — it’s a lovely little transceiver and paired nicely with this antenna for low-power portable work.

Thanks and Enjoy Your Radio

Thanks for reading — I enjoyed testing the SPX-100 and hope this write-up helps you decide whether it’s worth tossing in your rucksack for your next POTA or SOTA outing. Enjoy your ham radio and clear skies — hope to hear you on the bands.

For more information please visit our online store or alternatively contact us and our team will be happy to assist you!