Effective VHF Coverage

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Northern Blue
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Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 11:47 am

I appreciate that my 6w VHF radio transmissions from a sea kayak are going to be fairly restricted by ‘line of sight’ to the nearest CG base or repeater station, but so far this past week I’ve not managed to get a single response to my ‘radio check’ calls to Belfast CG, from various locations around Kirkcudbright, Fleet Bay and Wigtown Bay areas (SW Scotland).

I’m hearing the more powerful Belfast and Holyhead CG transmissions clearly, but wondering if the lack of response is entirely down to my location, or a fault on my radio. I can’t eliminate the latter until I eventually get a response from CG or another boat. My radio was fine last year when I got confirmation from Humber CG on the NE England coast, but I’ve not paddled over there this year to test it.

Chris Bolton
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Re: Effective VHF Coverage

Post by Chris Bolton » Fri Apr 26, 2019 12:00 pm

A little while ago I made a map of the main CG transmitters. It looks as if Caldbeck or Snaefell would be the nearest; you could check the line of sight from where you were?

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Re: Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 12:07 pm

Thanks Chris. Your link is taking me in to a live map, showing my current location, but no details of CG transmitter locations.

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Re: Effective VHF Coverage

Post by andynormancx » Fri Apr 26, 2019 12:21 pm

The link works fine for me (on Chrome on the desktop).

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Re: Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 12:27 pm

It’s obviously an iPad thing. I’ve just tried going in via Safari and it hasn’t helped. Unfortunately I’m away from home and my laptop at the moment, but will have a look when I get back next week. Edit - Just downloaded Google Chrome for the iPad and still no details on the map :-(

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Re: Effective VHF Coverage

Post by Chris Bolton » Fri Apr 26, 2019 2:00 pm

I've just opened the map and re-shared the link, but the address is still the same. As you say, it must be an iPad thing, and since it's a Google map it's probably Apple and Google not playing nicely. The map is zoomable so a static image isn't very useful, but the below is what it should look like for the Solway. The two transmitters are the purple blobs.
Image

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Re: Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 2:48 pm

Interesting Chris and thanks again. The Cumbrian mast might have been just out of line of sight, depending on its actual height above sea level, but the one on the Isle Of Man had a clear line to it.

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Re: Effective VHF Coverage

Post by mcgruff » Fri Apr 26, 2019 4:24 pm

Never actually owned a VHF radio but when I was looking into this I read somewhere that a "1/4 wave whip" (about 45cm long) can have a big effect on signal strength compared to a shorter, helical arial.

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Re: Effective VHF Coverage

Post by MikeB » Fri Apr 26, 2019 6:27 pm

You are transmitting on "high", and using the "INT" setting? Just a thought.

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Re: Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 6:37 pm

Definitely on high, but need to check the ‘Int’ setting. Nothing’s been changed in settings since I last used it at home, when Humber responded.

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Re: Effective VHF Coverage

Post by RichJ » Fri Apr 26, 2019 6:43 pm

Hi Northern Blue,
And please, please excuse my 'teaching to suck eggs' comments...
First off, are you fully depressing the ptt switch? ... The radio registering you are transmitting?
Secondly, is the antenna fully screwed on?
....Two very simple faults I have recently seen!

Rich

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Re: Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 7:57 pm

Rich, never a problem with sucking eggs.... and yes ‘TX’ is showing on the screen when pressing the PTT button and antenna checked religiously before every trip. (Recently retired emergency services with personal radio in use on a daily basis) :-)

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Re: Effective VHF Coverage

Post by Chris Bolton » Fri Apr 26, 2019 8:26 pm

If you're asking CG for a radio check and getting no response, and there's no other traffic audible, I don't know any reason why you couldn't ask 'any station hearing this' for a radio check.

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Re: Effective VHF Coverage

Post by Douglas Wilcox » Fri Apr 26, 2019 10:42 pm

Hi Northern I am not surprised your VHF handheld will not raise the coastguard anywhere on that coast, my 6 watt Icom doesn’t either.. which is why a bought a PLB nearly 14 years ago. Your VHF will work perfectly well reaching the coastguard on the other side of Wigtown Bay near Isle of Whithorn where there is a clear line of sight to Caldbeck. When I was shot at by a madman letting off two barrels of a shotgun above my head at Knockbrex beach I was not in VHF range after I had paddled quite hard to get out of shot gun range. From my caravan which is on the NW shore of Fleet Bay I can raise Belfast coastguard but then I am 32m above sea level. I still carry the VHF for inter group comms and for communicating with the Kirkcudbright firing range boat the MV Gallovidian.

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Re: Effective VHF Coverage

Post by Northern Blue » Fri Apr 26, 2019 11:43 pm

Douglas, my PLB is last resort back up, after the VHF and mobile phone. I was paddling with a mutual friend a couple of days ago and was told the story of the gunman at Knockbrex.... scary !!

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Re: Effective VHF Coverage

Post by Douglas Wilcox » Sat Apr 27, 2019 7:06 am

Hi Northern, I think the PLB is now the first resort when needing to call for help in a life threatening situation. There was a recent incident in the Forth to the east of Portobello when one of a very experienced pair of paddlers got into difficulty. Neither could raise the coastguard on their VHFs but the PLB worked.

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Re: Effective VHF Coverage

Post by Surferman » Sat Apr 27, 2019 9:43 pm

If your VHF has a screw on antenna, have you checked the center pin in the antenna is not broken? This happened to my Standard Horizon last year. I could hear only the most powerful transmissions and my radio checks suddenly never got answered. New antenna and everything is back to normal. Try another antenna if you can.

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Re: Effective VHF Coverage

Post by robhorton » Mon Apr 29, 2019 11:49 am

As others have said the range is likely to be the issue here but I have seen a few handheld VHFs stop (effectively) transmitting whilst still receiving so it would be a good idea to check it when you do get the chance.

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Re: Effective VHF Coverage

Post by Northern Blue » Mon Apr 29, 2019 9:16 pm

Thanks everyone for your pointers, I tried the radio yesterday at Auchencairn and got no response from Belfast CG or an ‘any vessel’ shout.

I just got back to Durham today and will be down the coast at the weekend, where I’ll try Humber CG or another ‘any vessel’ shout again. If that fails to get a response, I’ll try a new aerial.

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Re: Effective VHF Coverage

Post by Northern Blue » Sat May 04, 2019 2:53 pm

Radio is fine, Humber CG responded immediately to a test call from Blyth Harbour earlier.

Thanks for all the tips.

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Re: Effective VHF Coverage

Post by Rod81 » Sat May 04, 2019 5:22 pm

Yes Northern Blue, I can confirm it’s working, we picked you up loud and clear at Newbiggin Lifeboat Station.

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Re: Effective VHF Coverage

Post by Northern Blue » Sat May 04, 2019 6:29 pm

Rod81 wrote:
Sat May 04, 2019 5:22 pm
Yes Northern Blue, I can confirm it’s working, we picked you up loud and clear at Newbiggin Lifeboat Station.
Thanks for the confirmation Rod, it was obviously just the location over on the west coast, exactly as Douglas stated.

I take it neither yourselves or Blyth had any call outs ?.... the North Sea was a bit wild today. Exactly how I liked it when I was Sunderland ILB crew back in the ‘90s.

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Re: Effective VHF Coverage

Post by Rod81 » Sat May 04, 2019 8:16 pm

It’s been a quiet day up till now thanks, fingers crossed, we aren’t as busy this far north as the Sunderland crew but do enjoy the chance to get out in these conditions
https://youtu.be/89EvEpmIvO4

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Re: Effective VHF Coverage

Post by Northern Blue » Sat May 04, 2019 11:15 pm

Excellent video, makes me wish I’d never moved inland ;-)

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