2m Squalo - Gamma Match Surprises!

For a long time, I've had a half-finished 2m squalo sitting in the cupboard.  Having made a perfectly good SlimJim instead, it never really had much of a future here.

Motivated by some warm weather, I decided this week to finish what I'd started, and compare matching systems as I went.

I built two loops exactly the same size, as detailed in the International Antenna Collection.

Loop one had the specified gamma match, with RG213 inner and insulator running inside some microbore copper tube.

Loser: loop number one - Squalo with gamma capacitor matching.

Loop two had direct connection from the inner to one side of the loop.  I didn't include any form of capacitor (at the input.)

Winner: loop number two - Squalo with no (gamma) capacitor matching.  For the best SWR, the matching point of the gamma rod was slightly higher, and the capacitance wire at the top was moved to actually lie slightly within the central cavity of the facing tube.

Both loops could have their ends adjusted by means of thick copper wire soldered at each end (one end in the case of loop 2.)

Which one worked best?

Loop 1, the capacitor version, proved to have a high SWR after I took an analyser to it.  This is probably down to the gamma match connection point being too high up.  Loop 2, the non-capacitor version, came it at a perfect 1.06 at an extremely good 52 Ohm match at 145.5MHz.  This is how my SARK-110 analyser saw loop 2:

Great match for loop 2 (direct coupled gamma match)

Loop one was able to open GB3GD-Rat about 70km on the Isle of Man, running 5W from a hand held.  It could not open GB3GO-R, only about 30km on the Great Orme.  This was very surprising.  The access to the Isle of Man is aided by lots of ground gain, but both repeaters are line-of-sight to my QTH.

Loop two easily opened both repeaters, and I even had a perfectly comfortable QSO with a /M station using just 5W again.

So, the clear winner of the 'Squalo Shootout' is loop number two - the one without a capacitor.  Interestingly, the direct connection is also the method I use with my 40-10m three element magnetic loop, which has proven to be very successful.

Whilst this could be an OK antenna for base use, it has more use as a handy and very compact /P or /M antenna that can hang around in the boot somewhere.  I've a collapsible timber stand to stick it on, so no doubt I'll be getting more strange looks from people passing me, come this summer!

Any technical insights, as always, welcome!