G6GVI on 23cm

23cm is a fascinating band: it's the most accessible of our Amateur microwave allocations, with some commerically-available equipment around, but it's also a good starting-ground for microwave home-construction.

I did have an Icom IC-T81E handie for a while, but my main equipment has always been a home-built transverter, and at last (after 12 years) I've even got around to putting it in a "proper box":

So now I can take it out portable without the worry of it all coming to pieces in my hands!

My transverter takes an input of 2.5W on 2m, to produce 1.5W on 23cm. It will handle any mode from my FT817, and it also includes a -6MHz shift for operating through the repeaters. I often use a combined 20W PA and pre-amp, which I place as close as possible to the antenna (usually an old Jaybeam 15-over-15 dual yagi).

And in July 2009, I bought one of the first batch of the Alinco DJ-G7E handies imported into the UK. This is a handie with 2m, 70cm and 23cm, and is the first to include 23cm since the IC-T81E ten years ago. Read more about my experiences with this exciting new set here and see how I've used it mobile here. And follow my patch antenna development here.

One of the difficulties with operating nets on this band is that high-gain (and hence narrow beamwidth) antennas are often used. This means that in nets of three or more stations it can be difficult to find optimum beam-headings so that eveyone can hear one another.
Another problem is that some FM-only stations use vertical polarisation, whereas those with multimode capability are set up for horizontal. My Jaybeam antenna can only be mounted horizontally, but I've also got a simple home-made 14-ele yagi which I can set up vertically if required.
I'm also trying a home-made axial-mode helix antenna, which produces circular polarisation, and should give "just 3dB" loss with any linear polarisation. Follow this link for more details of helix construction. I used 2mm enamelled copper wire for the element, 22mm plastic conduit for the boom, and found a gauze kitchen splatter-screen which was just the right size for the reflector!

Many years ago I acquired a set of four 27-ele G3JVL loop-quads, one of which is now back in use on my mast. These are built on a circular boom, and so are very easily tipped over for slant polarisation. Andy G1HBE also uses this polarisation, which is a good compromise for either vertical or horizontal signals, even if it does look as if the wind has blown it crooked!
I've donated another of these to the Bolton Wireless Club for their portable operations.

And my most recent design is a double bi-quad whose broad beamwidth provides an obvious advantage in multi-way nets with stations on different headings.

As my home QTH is surrounded by higher ground, so the majority of my 23cm contacts are made when operating portable from the nearby hills. However, one of my best-ever contacts on 23cm was over 650km into Germany from home, during a troposhperic "lift" in February 2006.
But from home I can usually detect (using SSB mode) the GB3SE (Stoke-on-Trent) repeater/beacon, and occasionally (when conditions are helpful) the GB3CLE (Ludlow) and GB3MHL (Ipswich) beacons. And from nearby Winter Hill, I can also hear GB3MM (Wolverhampton) and occasionally GB3IOW (Isle of Wight).

Another interesting aspect of the band is the strong reflections from structures (e.g. gasworks) which can sometimes help signals to get around obstructed paths. As an example, I can only work MW1FGQ (who is South-West of me) from home by using reflections - the best signal I've heard from John was when I was beaming East, pointing at Bolton Town Hall!

Here are some of the contacts I've made in recent years using my transverter: 2005, 2006, 2007.
But as can be seen from the graph below, 2009 and 2010 have been bumper years for me on 23cm:

Although all my long-distance SSB contacts have been made during contest sessions and tropo openings, I'm also keen to get more local contacts (particularly FM) too. I know quite a few stations in this area who have 23cm capability but hardly ever use it: this is a shame considering the effort they went to to get on the band in the first place!
So here's my list of local (to NW England) stations with 23cm capability with whom I've spoken on air recently:

If you'd like to try a sked on 23cm, then please get in touch.
We're also planning to establish regular 23cm activity sessions: email me if you have any suggestions.

It's also worth keeping an eye on the SOTA-Watch site for 23cm activity from local hilltops in the Peak District, Pennines and North Wales. And have a listen during the scheduled contest sessions which include 23cm.

For the Spring of 2009, Shaun G7IEI kindly loaned me his FT911 handie, which I used portable from the hills on more than a dozen occasions. Each time I had at least one answer to my CQ calls, and I then managed most of the QSOs on 100mW power!
And Wayne 2E0BVJ has also had some contacts using an old Standard C568, which provides just 35mW on the band.

In Summer 2009, the Bolton Wireless Club acquired an old Microwave Modules transverter and loop-quad antenna for Club use, so listen out for G0BWC/P from the hills, and more of our members trying out the band from home.

I'm now evaluating compact aerials for convenient hilltop operating: something small enough to be carried in my rucsack, and then clip onto the top of my walking-stick, which can serve as a small mast. The first rough prototype of a 6-ele beam proved the mechanical concept (and on a calm day didn't even need any additional support other than the pointed end of the stick pushed into the ground) so one day I'll make a more accurately-dimensioned one. But since then, I've developed a portable patch antenna which probably has less gain, but is much more robust.

In December 2009 I enjoyed the loan of a Yaesu FT736 with the 23cm module fitted. This provides around 10W output from a fully-featured base-station set. Many thanks to David G8UVE for letting me have a play with it, and also for allowing Chris G4HYG to borrow it to score more points for the Bolton Wireless Club, and help them to win the RSGB 23cm Club Championship.

And finally, in March 2010 I acquired a "proper" 23cm radio of my own - an old Icom IC1271E - a large "mobile" multimode (although it includes an internal mains PSU, it will run direct from 12V too). This set used to belong to my late-lamented friend Dave 2E0DCR, and it now takes pride of place in my shack. My first QSOs with this set were in the UK Microwave Group's "Low-bands" contest in March 2010 - I had four contacts operating from a friend's QTH in the Wye Valley. Then in June I had 20 QSOs from Winter Hill, including one down into Wiltshire. And then in December 2010, I managed to obtain the Icom GaAsFET masthead pre-amp for it, which means that I'm less likely to miss signals, no matter where I'm beaming. I'm sure that I'll give it lots more use over the coming months, and may even loan it to some of my friends in the Bolton Wireless Club now and again!

I also operate FM-ATV on 23cm: details of this can be found here.