ANTENNA SWITCH PROBLEMS

MyDEL CO-301N 3-Way Heavy Duty Antenna Switch

I was just reading something on VE9KK's Blog about buy cheap - buy twice and it reminded me of some antenna switches that I purchased from a well known ham store here in the UK. These switches are very common and I'd refer to them as mid-priced (because they're certainly not very cheap).

I purchased two of these switches and they've had very light use but one of them failed at the weekend. I noticed when detaching an antenna lead that the SO-239 was loose in the body of the switch. I had no choice but to open it up and have a look inside.

With the back panel removed, it was clear to see what had gone wrong. I had assumed that the SO-239's were screwed into the aluminium body of the switch, but they're not - they are a tight push fit and there's evidence of a bonding material (glue).

The centre-pin of the SO-239 is soldered directly to a terminal and a brass wiper arm sweeps across and makes contact with the terminal when you turn the switch.

The attaching and detaching of cables over the last 11 months has obviously stressed the SO-239 to a point where it has come loose and the twisting effect of screwing on (or unscrewing) of a PL-259 has broken the rather weak looking solder joint.

I can see from the design and the quality of the solder joint that the center connection might be the next one to go wrong. I shall have to resolder the broken one and try to add some additional bonding material to all 3 connectors to avoid them turning in the future.

These switches are about £47 each, so I don't think it's unfair to expect a little more from them. And looking at the way that the selector-blade makes contact with the SO-239's I'm surprised that you can put 1,500W through them. Wow!!

I now buy antenna switches from CROSS COUNTRY WIRELESS here in the UK. They are more expensive, but superbly made and have fantastic isolation between ports.

73, Tom, M7MCQ.