Back in 2013, I fitted a new Diamond X-50 colinear on the side of the house. A 12 metre length of UR67 coax connected it to the radio.
Now, the X-50 came fitted with an N-Type socket and when I mentioned at the local emporium that I’d never made up an N-Type before, I was advised that they were a bit fiddly and it would be easier to use an N-Type to SO239 adaptor.
So I did.
It all worked really well and was certainly an improvement over the Slim Jim I’d had years before.
But over the years, I noticed a drop in performance. GB3HR, which I had been able to get into with little problem, slowly slipped into the noise and eventually became unreadable with me. At first, I thought this was due to the repeater owners reducing selectivity, to try and prevent the troll that sits on there from getting access. But then I noticed other issues.
Eventually (two weeks ago), I decided to replace the X-50 with an X-200, giving slightly more gain, and also replace the UR67 with some Ultraflex10 – again providing slightly less loss.
The difference has been tremendous! So much better than I had estimated with the 2dB gain I’d calculated.
So, I looked at the X-50, to see if I could see any reason why it had been under-performing and I noticed that the aforementioned adaptor was at fault. Whilst it looked clean and to be in good nick, the petals on the SO239 part must have shrunk slightly, as when I undid the PL259 connector from it, the weight of just one metre of RU67 cable was enough for the plug to slip out of the adaptor. It looked perfect, but was really loose fitting. I have tried other PL259 plugs and they all fall out, just the same.
So, I’m guessing the adaptor was the cause of this underperformance, all along.
The new aerial doesn’t have an adaptor, as I fitted an N-Type directly to the cable: yes, it’s a bit fiddly, but really not that difficult, it turns out.
And now I know how to do them, I’ll be fitting them on all my VHF/UHF cables.
And I’ll definitely not be using any adaptors again!