Posts Tagged ‘Trouble shooting’

WHAT an SWR of 99:9!!

The other evening I had an opportunity to get on the air it has just been to long and I was very excited about spinning the dial around the HF band! I ran the coax out to my MFJ 1788 on the balcony and fired up the K3. I jumped on 20m were not to much was happening but on 30m there was some Dutch DX that was calling CQ so I thought I would give them a go. Prior to calling my SWR on the loop antenna was tuned to 1.2:1 BUT when I started to call the Dutch station my SWR readout on the K3 magically became 99.9:1!!! It was like the coax had been removed from the antenna and was sitting on the ground. It was late so I wanted to look into this at a later time, this evening was the later time so I hooked the antenna up and gave 20m a go and the SWR once again on the K3 was showing 99.9:1. It was time to trouble shoot, was it the coax, MFJ 1788 antenna, the K3 or my LDG antenna switch? The first thing I wanted to do was to remove the antenna as the problem.
Without LDG antenna switch
I removed the coax from the antenna and in it's place put a 50 ohm dummy load. In a way I was relieved to see the 99.9:1 SWR thus removing the MFJ 1788 from the problem. Next I bypassed the LDG antenna switch and low and behold the SWR now was 1.1:1 and me saying thank god it was not my K3! So it would seem the LDG  antenna switch is the problem so I took the switch cover off and looked around. I cleaned the SO-239 connectors, check the internal connections and all seemed to be great. The only problem spot to me could be the switching relays with internal contact troubles? After exercising the relays the trouble in the LDG antenna switch seemed to be ok. If the trouble comes back this is a 4 position switch and I only use 2 positions I could swap out relays and look at ordering all new relays. At this point all seems to be working well but stay tuned to see if relay swapping and ordering is in the near future.
Relay in the LDG antenna switch

Water + PL-259 = no radio for the day!

The waterlogged  PL-259
Well FINALLY I was able to get some radio time it has been so long and really there were no good reasons just what I call excuses!  On Saturday afternoon it was time to get some long over due radio time in. I ran my coax jumper  to the 1788 MFJ loop from my K3 radio, I settled into my radio chair and flipped the switch…..and……it was time for Murphy to visit me! With the MFJ loop you are supposed to tune the loop for peak noise and this was just not happening. I was getting numerous peaks but the SWR was all over the place! I thought about it for some time and after trying numerous ideas it finally hit me! I have a 6 foot coax tail on the loop and via a coupling I connect the coax from indoors. It was really raining the last few days and the balcony was very wet and "normally" my outdoor coax tail is in a plastic zip lock bag. This past rain storm was also accompanied with a strong wind and somehow the coax was removed from the bag and was in the water. I removed the coax and checked it with my ohm meter and it showed a high resistance between the centre conductor and shield. So it seems water has made it's way into the PL-259 connector and after installing a new piece of coax and doing some check with great results it was time for bed. My loop is supported by the MFJ tripod. I have a cover over the loop it to help disguise it and kinda makes it look like patio furniture. There is lots of wind being high up and on the lake so the cover has to be secured around the centre pole of the tripod. It's great that the antenna works perfect with a cover and with it secured as well I just want to come up with an easy way to connect and disconnect the coax from the antenna. I don't want to remove the cover or un-secure it from the centre pole. Any ideas from ham world would be approbated.
A shot of the balcony antenna open for suggestions. 

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