Sat 15th Apr 2017, 02:35
Adding a Remote Coax Switch
I now have two HF antennas now on my tower. A OCF windom and a Hex Beam
I was using BuxComms line isolator B2KLISO in the coax feed to the Windom. It was recommended since my coax run was more than 75 feet.
I am adding a remote coax switch now.
The Coax run is still over 75 feet.
If I put the line isolator in between the control box out connection and the coax run, I don't know if it will cause a bad situation.
thanks Ken K5XOM
Last edited by K5XOM; Sat 15th Apr 2017 at 03:33.
Sat 15th Apr 2017, 13:27
I suppose the only way to check is run the system with and without, and check your SWR on both.
I run a remote coax switch for my Comet H422 and Diamond X50. I know the relays are only rated to 150MHz, but I can still comfortably operate half way through 70cm before the SWR shoots up, so it works better than it should on paper.
Sat 15th Apr 2017, 15:15
Where do I place the SWR meter now? The way I have equipment setup now is, Transmitter, SWR meter, remote coax control switch, Line isolator, coax run.
I am noticing higher swr's than before without the switch. However I am connected in a different coax run now. I need to do so checking and elimination to see what is going on there.
But primarily, where would the SWR meter be connected now when I have a coax switch in the game. Should the meter be before the switch or after the switch.
Sat 15th Apr 2017, 16:27
Leave the VSWR Meter in-line behind your transceiver as any change would show up at that measuring point. Moving a VSWR / RF Wattmeter would change any measurement greatly and cause confusion.
Sun 16th Apr 2017, 01:47
I am getting better performance with the remote switch completely removed. I have to do some more checking tomorrow.
Mon 17th Apr 2017, 01:19
Well, I don't know why the Hex beam doesn't like the remote switch.
SWR's are high. And received signal is strength is very low.
SWR's with Dummy load on remote switch is good.
OCF Windom antenna on remote switch is also ok.
SWR's are flat when Hex Beam is fed directly from transmitter.
Looks I will be running another coax to feed the Beam. $150 down the drain.
Last edited by K5XOM; Mon 17th Apr 2017 at 01:23.
Mon 17th Apr 2017, 09:12
Don't have any details to be able to help. A decent switch will have low insertion loss and an in to out VSWR of 1:1, so something is adrift. Can you you put up a link to the switch? Normal coax switches do exactly that - simply switch so if you have loads of loss, or bad VSWR it will be the switch, the connectors or the coax - cannot be anything else? If the switch is old or perhaps water compromised - these things can cause your problem, but you've provided no info yet?
Mon 17th Apr 2017, 13:52
Yup, sounds like the relay has a dry joint or something. Rip it apart and re-solder the connections (or get it refunded).
Any old relay will do for H.F. it doesn't need to be anything special until you go above 144MHz, provided the contacts are big enough and your SWR is low enough to begin with...
Mon 17th Apr 2017, 14:13
Mon 17th Apr 2017, 19:11
ok, you know the long coax run is good, you know the antennas are good, and you know one output of the switch and the one coax jumper to an antenna is good..
you know that you get a bad reaction with the hex beam from one output of the switch and one coax jumper... you still have two places on the switch to try and of course the coax jumper used to connect the hex beam up with...
you might just switch the antenna positions and see if the problem moves from one antenna to the other.
I would try another output on the switch and then replace the jumper you used...
take the troubleshooting steps in order and try them all before going to spend more money.
Tue 18th Apr 2017, 03:17
Finally late this afternoon I found the culprit. A 90 degree coax connector was opened. I couldn't believe it. I was using three of those connectors in the switch box connections because I mounted the sw. box in a plastic box with a door made for putting electrical things in to get them out of the weather. So I had to use 90 deg connectors. When I went to trouble shooting, I did it without the 90 deg connector in the circuit. Like when I put the coax to dummy load. Or when I by passed the switch to connect to the OCF antenna and or hex Beam and was getting flat SWR's When I went back to the switch box to trouble shoot I was using a bad 90 degree connector specifically on the Hex beam. I made a lot of trips back and forth. I have been operating to night on the Hex and am really happy now.
Tue 18th Apr 2017, 22:12
You can scrape the contacts of the connectors and re-tension them with a pick or small screwdriver, a little copper grease will stop them from corroding too quickly.
PL/SO239 connectors are not waterproof, so always cover them in self-amalgamating tape if used outside...
Wed 19th Apr 2017, 03:53
Yeah. but this connector is definitely open. I don't know how it is made inside, but I might cut it open and find out.
Tags for this Thread