Tonna at Sunset
I’m a fan of the 6m band. It fascinates and frustrates me in equal measures, which is part of its appeal. It’s unpredictable, you can be working local stations within 50km of your QTH for some time and then all of a sudden a Portugese station will call you and they’re 59+40dB drowning out anything local. Sporadic E openings are a lot of fun on the band and it supports other propagation forms like TEP and even F2 at the peak of the sunspot cycle (not this one!).
I only operate on 6m when I’m out portable and I have two antennas, both of which I feel are suitable for portable use. My 6m operating is mostly a mix of SOTA activations and contesting, although I did go out for one or two of the SpE openings after work on a summers evening.
I have the SOTABeams SB6 Beam and the 6m 5ele Tonna 220505 Yagi options for my 6m portable operations and am pleased with both of them, however in terms of performance there’s not too much to pick between them. This is surprising given the SB6 Beam is essentially a 2 element Moxon, while the Tonna 220505 is a 5 element monster Yagi and much, much bigger!
6m Moxon Ready to Go on the SOTA summit of Long Knoll
Surprisingly the 5ele Tonna Yagi has less gain than the SB6 beam. I suspect the SB6 beam is broader, but it is also much smaller and lighter! The only trouble I have (being in IO91) is that I’m surrounded by QRO contesters and it’s harder to null them out with the SB6 than the Tonna.
Tonna at Dusk
I’ve been very impressed by the performance of the SB6 6m antenna. I’ve used it in numerous contests and on SOTA activations this year and it’s a tough one to beat for portable use.
Side by Side Specs
Here’s how the two antennas compare, these are taken from the published specs and also include some of my (subjective) opinions based on personal experience:
| SOTABeams SB6 | Tonna 220505 5ele Yagi | |
| Antenna Type | Moxon | Yagi |
| Gain (calculated) | 11.1dBi | 10.1dBi |
| Cost | £59.95 (from SOTABeams) | £89.95 (from Martin Lynch & Sons) |
| Front to Back ratio (calculated) | 24.6dB | 23.8dB |
| VSWR | <1.2:1 | 1.2:1 |
| Power rating | 150W | 500W (never used more than 10w myself!) |
| Weight | 700g | 4.9 kg |
| Overall Length | 2m (width), 0.5m (depth) | 3.4m (long) |
| Connector | BNC | N-Type |
| Time to Erect | ~2 minutes | ~10-15 minutes |
| “Erectability” | 8/10 – Very easy to keep up in the air using a lightweight fibreglass fishing pole. It does catch the wind a bit, but this is pretty much unavoidable with any 6m antenna, bar a vertical. | 5/10 – Quite difficult. This is a lot of metal to hold up in the air on a windy hill top! I use an aluminium mast guyed at two separate points, using 6 guying ropes in total. This certainly needs more engineering if it’s to stay in the air. |
| Strength | 5/10 – Quite fragile (made from fibreglass), the feed point broke off on the first use due to it hitting the ground. It’s not rock solid by design and this is how it achieves its light weight nature. | 9/10 – Not fragile (made from aluminium). |
| Directionality | 6/10 – Quite directional. You can easily peak signals by turning it slightly, although it feels quite broad. This is no bad thing sometimes, as your signal will gain wider coverage, perfect for SOTA but not ideal for contest DX or to null out local QRO stations. | 8/10 – Good directionality. Despite the similar (predicted) radiation patterns this antenna does feel more directional. I feel like I can pull out weaker DX stations than I can with the SB6 and the beam is a bit narrower. This is all subjective of course! |
| Visual Impact | 8/10 – Pretty low visual impact for a 6m antenna! I feel more comfortable using this one in public locations. An added bonus is that you can paint the white fibreglass poles to make it blend in a bit – sky blue or battleship grey?! | 4/10 – There’s no hiding this antenna, people see it from miles away and it certainly gets some looks. I wouldn’t feel comfortable using it on any busy public hilltops. Perfect for UKAC use in the dark though 🙂 |
SOTABeams SB6 Radiation Pattern
6m 5ele Tonna Yagi Radiation Pattern
Using the SOTABeams SB6 During the RSGB 6m AFS
The SOTABeams SB6 Up Nice and High During a 6m UKAC Contest
Another bonus of the SOTABeams SB6 is that you can quite easily make a 2m version with just 5 spare fibreglass rods, some wire and two plastic separators. SOTABeams do offer a 2m version (SOTABeams SB2), but I wanted to make it myself. You could also quite easily make a 4m and even a 70cms version, but for 70cms I’d prefer a few more elements.
2m Moxon I made from spares on the SOTA summit of Fan Brycheiniog (GW/SW-003). I worked into Ireland over a sea path using FM on here, so it also performs rather well!
Conclusion
You can probably guess that I’m quite fond of the SOTABeams SB6, I still find it amazing that such a small and simple antenna can punch well above its weight and compete with a 5 element Yagi, I’ve still not got my head around this!
If I want to enter a contest seriously I’ll still reach for the Tonna, as I feel the directionality is better on this, but for everything else I’ll pack the SOTABeams SB6 without thinking.
For my operating needs the SOTABeams SB6 clinches the deal and if I could only have one it would be this!
Have you used anything else for portable 6m operation? Leave a comment below!
6m is certainly an interesting band. I had mixed success in the UK back in the 90s when I was first licensed – here in DL I haven’t bothered due to the extra paperwork necessary for 6m operation. Also, you have to be available by telephone at all times when transmitting, making portable operation nigh on impossible!
Thanks for your comment Robert and interesting regarding the status of the 6m band in Germany. I thought you couldn’t operate at all on the band from DL, but I wasn’t too far off the truth!
Interesting comparison you give. And helpful. I ventured out with a 6m home brew dipole yesterday but that SOTA beam Moxon has me hooked.
You’ll find you will do much better on 6m with the SOTABeams Moxon compared to the dipole. That being said a dipole can work into Europe during a good Sporadic E lift. 6m is an interesting band!
73, James M0JCQ
I looked more into this, have you seen the Super Moxon as appeared in RadCom in 2010?
I’ve not seen this article Ben. How does it differ to a regular Moxon (which seems to be a great antenna if you want gain but are restricted by size)?
You convinced me to order the Sotabeams SB6 – but it has been discontinued this week.
I’m sorry to hear this James, a member of my club also tried to order the antenna this week and found the same.
A real shame, I used it yesterday and worked a pile up of EU stations on 6m for 2 hours 🙂
A homebrew 6m Moxon wouldn’t be too hard to make, there’s plenty of plans online.
73, James M0JCQ
It seems that the Par Electronics 6m ‘stressed Moxon’, SM-50, has a big fan club – 50 reviews on eHam and rated 5/5. This looks very tempting but will carry shipping/import charges from the US. I can’t identify an EU distributor. Anyone?
James
Just came across your blog and like it a lot. Six meters sounds like fun I have never had a 6 MTR capable rig so it is always interesting to hear about other hams experiences with the ” magic” band. Great job with your blog, I will look forward to more posts!
73!
Glad you liked it Mike. It’s a really interesting band this time of year. You’re bound to get a 6m capable rig at some point, anything relatively new seems to come with this band.
73, James M0JCQ
Hi James,
I am planning to build a 6m Moon due to the fact that I build most of my antennas by myself.
Could you please let me know the diameter of the used fiberglass rods?
TNX es vy 72/3 de DM5TU – sTef