Tuesday, April 8, 2014

Playing with a HyGain 18-VS

The other month we had our local radio club junk sale, everyone brings in something to sell and we have a good natter and lots of items get exchanged. It’s normally a very good event and gives all the members a chance to catch up and see what we are all up to. 

I brought in a tired looking 2m collinear and my home brew 2m yagi to be redistributed, both items had been sitting in the shack doing nothing and I needed the room for other projects plus they could be put to good use by another amateur instead of sitting there doing nothing. 

Whilst rummaging around looking at what other people had brought in to sell I noticed a chap with an old Hy Gain 18-VS vertical multi-band antenna. I vaguely remember my brother-in- law having one but always being a little frustrated because on each band change you had to go out to the antenna and manually alter the connection to the coil. To add to his frustration he always forgot the exact position he should set the connection and always ended up digging out the antenna analyser and resetting the SWR! 

This particular antenna in the sale looked like it was all there, but it certainly needed a good clean, the owner only wanted £10 and considering that a new one was over a £100 I thought I’d buy it and have a play to see if I could do something with it. 

After giving it a good clean and checking the manual I immediately realised that the antenna had been altered. Instead of the usual tatty coax connection above the coil, a previous owner had put in an SO 239 socket at the bottom of the antenna to make things a bit tidier, however, with that connection in place the coil was being bypassed therefore was useless. 

Investigating further I realised that the antenna had been set up as purely a mono bander, the previous owner had obviously given up on the state of the coil and from notes in the manual they mentioned about removing 12” of tubing, or he must have been like my bother-in-law and got fed up with changing the coil every time he wanted to alter bands! 

The two coils after a quick clean up, no doubt in the future I will put them to use.

With the antenna originally at 18ft in length I rightly guessed it had been reset as a mono for 20 meters but in its present state it wasn't going to transmit or receive anything. So I took it all to bits, and started from scratch, the coil looked in a sorry state, it had been glued together at some stage and so I removed it altogether since in its present condition it was certainly not going to work. 

After a good clean and checking the rest of the connections I reset the antenna length to roughly 16½ ft and connected it up to my analyser, all now seemed much better with an SWR of 1:1. 

So then I planted the refurnished antenna next to my 30 meter vertical via an old piece of scaffold pole hammered in to the ground. Using the 30 meter ground wires I attached some thick copper wire to the ground plate and I was now all ready to connect to the radio and have a listen on 20 meters. 

You wouldn't believe there are 30 odd ground wire connected to that plate!

Sure enough signals were coming in and after double checking everything was correctly connected I did a quick transmit through the dummy load, everything worked perfectly. Calling CQ I immediately got a reply with a signal report 599 from another QRP station in Italy. 

The HyGain planted next to my 30 meter vertical

Very pleased with the outcome I did some further testing against the 20 meter portion of the cobweb; however the cobweb was definitely stronger no doubt because its thirty odd feet up in the air and clear of all surrounding objects. But never the less it was great to get hold of an old Hy-Gain and bring it back to life!

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