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Discussion Starter · #1 ·
I have had 2 fail in 6 years and not sure why. It hadn't happened before.
One was a Glomex and the other a Banten - standard sort of kit in a 1.5m fiberglass tube. As far as I can tell the insulation has shorted somewhere because I have zero resistance between the core and the shield of the co-ax although I cannot see where its gone. I have tested without the connector so its not there and there are no visible cuts or breaks nor evidence of water ingress so I'm wondering whether its just an unfortunate co-incidence or something else which I haven't figured out.
Any ideas welcome please
 

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I would guess water ingress. Years ago, in the days of CB radio, I used to get water in the loading coil that had the same effect. With that, it could be stripped dried and resealed and good to go again. Probably not the case with your VHF aeriel....
 

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As far as I can tell the insulation has shorted somewhere because I have zero resistance between the core and the shield of the co-ax although I cannot see where its gone.
You will see a short circuit if measuring with a multimeter as both connections connect to the same internal brass aerial wire.
The Aerial only exhibits its 50 ohm impedance at the VHF frequency range.
My guess is also water damage but :
Way to check is via an SWR meter.
I believe Brian PBSBAC secretary may be able to lend you one Max
Peteg
 

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Discussion Starter · #5 ·
You will see a short circuit if measuring with a multimeter as both connections connect to the same internal brass aerial wire.
The Aerial only exhibits its 50 ohm impedance at the VHF frequency range.
My guess is also water damage but :
Way to check is via an SWR meter.
I believe Brian PBSBAC secretary may be able to lend you one Max
Peteg
Thanks Pete, much appreciated
 

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Cant find out enough info on this to recommend Neill .A concern is sensitivity as you will only be transmitting at approximately 5w and 20watts the unit linked handles up to 1000watts so don't know accuracy at low powers.

Plenty of used ones on the bay just stay away from the cb ones as they cover lower frequency range.
For a bit more money these seem pretty good and simple to operate. Don't forget the additional patch lead needed to connect from box to radio. they have internal rechargeable battery power. plenty of reviews on you tube. A dummy load is also a worthwhile purchase to prevent damage if you connect radio but not aerial and press transmit. Transmitting without dummy load or aerial connected WILL damage your transmitter
https://www.amazon.co.uk/Mcbazel-Su...d-search-10&pf_rd_t=BROWSE&pf_rd_i=1348435031
 

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Re antenna failures I have had 2 glomex failures over the last few years. The first unit was a 1.5m one and water had corroded the internal soldered joint inside the radome sleeve. This was easy to repair as radome could be slid off for access, but because the waterproofing was poor I had to repair a few times. Eventually decided to replace with new 2.5m glomex.
This failed due to coax being crushed between handrail and stainless swivel mount.This was a pig to fix as couldn't gain access to the internals of the aerial to connect new coax it had double radomes bonded together so could not be removed.
In hindsight I should have sent it back for warranty repair but decided to sort it myself.
I ended up cutting a window about 15 cms long and about 2 cms wide towards the bottom of the aerial with rotating cutter which once removed allowed access to the coax(Assumed that was where the coax was soldered to the brass wire WRONG),
Fished a new coax up through the aerial and soldered and insulated to original.These aerials seem to have the solder connections at the tip of the radome rather than the base.
Once sorted I glued in place the removed "window parts" using superglue and baking soda to fill the gaps and wrapped in white electrical tape.
Touch wood been good as gold for the last 12months
 

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Cant find out enough info on this to recommend Neill .A concern is sensitivity as you will only be transmitting at approximately 5w and 20watts the unit linked handles up to 1000watts so don't know accuracy at low powers.

Plenty of used ones on the bay just stay away from the cb ones as they cover lower frequency range.
For a bit more money these seem pretty good and simple to operate. Don't forget the additional patch lead needed to connect from box to radio. they have internal rechargeable battery power. plenty of reviews on you tube. A dummy load is also a worthwhile purchase to prevent damage if you connect radio but not aerial and press transmit. Transmitting without dummy load or aerial connected WILL damage your transmitter
https://www.amazon.co.uk/Mcbazel-Su...d-search-10&pf_rd_t=BROWSE&pf_rd_i=1348435031
Many thanks for the reply. The one I posted says 5% accuracy is that no good.
 

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Neill,
The link you posted didn't have any decent info to make a comment on however this model
https://www.ebay.co.uk/itm/Zetagi-H...677620&hash=item2aa5503190:g:~tkAAOSwTLlZvpyW

although working fine for SWR over the 3-200Mhz range is not suitable for measuring transmitter power accurately as it is limited
to 26-30 MHz range.
So I assume the 102 model is the same. They are for CB radios effectively

If you just want to measure swr either are ok but I would personally want to measure transmitter power against a dummy load to have confidence in my equipment so would choose alternative devices
Hope this helps
 

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Neill,
The link you posted didn't have any decent info to make a comment on however this model
https://www.ebay.co.uk/itm/Zetagi-H...677620&hash=item2aa5503190:g:~tkAAOSwTLlZvpyW

although working fine for SWR over the 3-200Mhz range is not suitable for measuring transmitter power accurately as it is limited
to 26-30 MHz range.
So I assume the 102 model is the same. They are for CB radios effectively

If you just want to measure swr either are ok but I would personally want to measure transmitter power against a dummy load to have confidence in my equipment so would choose alternative devices
Hope this helps
Thanks again for taking the time to reply. I now understand what checks are needed to ensure optimal settings for the radio.
 

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Max
Did you get your antenna problem solved, I've got a professional VSWR/Power meter that covers the VHF frequencies.
I can't do anything at the moment as I'm self isolating prior to a cataract op. As soon as that's done and I'm able I'll be putting my boat back on it's berth, just along from you on F Pontoon.
Cheers
Brian
 

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Discussion Starter · #13 ·
Max
Did you get your antenna problem solved, I've got a professional VSWR/Power meter that covers the VHF frequencies.
I can't do anything at the moment as I'm self isolating prior to a cataract op. As soon as that's done and I'm able I'll be putting my boat back on it's berth, just along from you on F Pontoon.
Cheers
Brian
Hi Brian
Not yet so I'd really appreciate that. When I see your boat is back I'll drop you a note.
All the best with the op
Thanks
 
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