UN-UNBELIEVABLE.

SUDDEN DEATH

A couple of weeks ago I ran an SWR SWEEP on an EFHW which runs to the back of my conservatory using the NanoVNA and the RigExpert. Everything was looking good. Then last night I decided to do the same on my other EFHW (wireantennas.co.uk) which runs to the shack - and everything was definitely not alright!

I don't spend a great deal of time in the shack except in the Autumn and Winter months. It's a South facing room and it gets unbearably hot in the summer, so I tend to sit in the conservatory with the large doors wide open or even outside in the garden. As a result, it's been a while since I used the shack antenna.

When I tested it with the RigExpert, I was presented with a near infinite SWR reading and I thought it might be my antenna switch throwing up a fault, so I connected the RigExpert directly to the coax coming through the wall, but got the same results.

I checked the coax cable (Messi & Paoloni) but could find no obvious problems. Unfortunately, I wasn't able to reach the Un-Un to check inside it because it was too high up for me, so I had no choice but to cut the coax at a point where I would be able to insert a joint later.

Once the Un-Un was down, I could see that the Messi compression-type PL259 was still in perfect condition thanks to the quality of the connector itself and also thanks to the self-amalgamating tape I'd covered it with.  I removed the lid of the transformer and could see that the ferrite looked to be in great condition but the main connection to the SO-239 was not looking good. As soon as I touched the wire, it was obvious that the soldered connection was loose and it simply came out.

Now bear in mind that this thing gets very little use and never more than 10W. It does, however see more FT8 use than SSB, but that shouldn't make a difference at that level of power? This is a 100W rated antenna (probably with a 30W data rating). I’m very disappointed 😢

Anyway, there's no use moping over it - it needs replacing, so I ordered a new one from UKANTENNAS and it has just arrived. The first thing I noticed about it was the size and weight - it’s smaller, but 100g heavier!

I'm not going to throw the other one away of course, I'll order a new SO-239 and clean things up. The repaired Un-Un will then be available for portable work.

Looking back, I recall buying my 17M Double Bazooka from WireAntennas and not being very happy with the quality of construction. Now that the EFHW has failed, I'll probably avoid buying from them in the future. Sorry 🤷‍♂️.

The UK ANTENNAS 49:1 is very well built and once connected to my wire, produced good readings across the bands. It’s good to be back to normal in the shack.

73, Tom, M7MCQ.