Radio check over

john_morris_uk

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If you're testing the vswr of the antenna, why would you have anything other than a very short flylead between the meter and the antenna?

Surely people don't attach it at the radio end of the coax? That wouldn't tell you anything useful and may give a false sense of security.
My antenna is at the top of the mast. It hasn't got a PL259 plug on the end of the coax. It's got a special connector that goes straight into the base of the antenna unit.

Besides which, are you suggesting I or others will be taking a VSWR meter up the mast to test the antenna matching? Even if I wanted to I couldn't as I'd need to temporarily fit a BNC or N connector or PL259

It's not going to happen... Hence my original criticism of trusting implicitly a VSWR meter. They are invariably used with a short patch lead from the back of the VHF and it doesn't tell the whole story and can deceive you. Useful, but use with caution.
 
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chrisclin

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Every boat I've met carries a handheld VHF just check with that.

this insistance that it is just the set itself you are testing worries me on a couple of counts.
First, all my problems have been because of corrosion in the aerial - only noticeable whn transmitting. Testing with a handheld often means the signal doesn't go through the mast aerial at all - it's too close.
The point about testing everything else such as EPIRB - yes I test it as they recommend. The VHF course I did a fw years ago included a section on radio checks and the old Clyde Coastguard told me they were quite happy to do them - it meant you knew what to do.
That said, I don't usually do them except when I've been fiddling with the wiring or when I haven't spoken to someone for a while.
 

Bru

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I've changed my mind after yesterday. Non stop litany of "blah, radio check please ", over and over on 16

Wish they'd all shut the... heck up!
 

snowleopard

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Today. :disgust: :disgust: :disgust:

Falmouth coastguard, this is annoying boat, radio check please over.

.........

Falmouth coastguard, this is another annoying boat, radio check please over.

I heard it too, all day yesterday. Plus Brixham too. I admired one guy who asked any vessel in his immediate area for a check and was happy to oblige.

In these days of DSC there is no reason to be constantly calling your mates on 16, just dial their MMSI and go straight to a working channel. Then there was one who called his mate and said 'switch to 67'. I bet that pleased Falmouth CG.
 
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ShinyShoe

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I admired one guy who asked any vessel in his immediate area for a check and was happy to oblige
Did he call on 16… seems that doesn't achieve much that calling CG would have. CG have signal strength info which is part of their response.. Weak but readable. Loud and clear. Etc.

My preferred approach is:
Formal radio check after install and any reinstall.
DSC auto test call prior to departure. Checks you can transmit and receive. Assume receiving voice anyway so only thing not tested is voice transmit.
Then for any meaningful passage a DSC call to CG with passage plan.
Of no passage plan and if its not a significant journey but wanted to test then voice call my hh on a working CH. The DSC call has proven the aerial so the voice call is to prove the mic.
 
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A good solution is using a cheap zetagi inline SWR meter you can check your output power and any reflectance due to poor antenna etc, It gives me piece of mind that the full power is getting out when required.( you can also check your buddies boats as well :)
 

john_morris_uk

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A good solution is using a cheap zetagi inline SWR meter you can check your output power and any reflectance due to poor antenna etc, It gives me piece of mind that the full power is getting out when required.( you can also check your buddies boats as well :)

I just wondered whether you had noticed my previous post:

Finally the. 'Simple device' (I imagine you are referring to a VSWR meter) can't tell the difference between a bit of soggy string or an antenna cable full of salt water and corrosion. In fact the latter (with no antenna on the end at all) can give a very good VSWR reading. A long length of brand new lossy coax shorted out at the end might have an SWR of only 2:1 or so. (Having an accurate SWR meter and measuring the SWR of open ended and shorted coax is an old RF engineers way of measuring the loss of the coax- there are tables and graphs available...)

A VSWR meter is a wonderful and simple device but the results must be viewed with caution for the reasons I give. If you are totally confident that the co-ax is in excellent condition and is of good quality and low loss then that will give you added confidence, but even then the antenna can in certain circumstances produce misleading readings. Its very rare for the latter to happen, but the false readings from lossy and corroded or water filled coax giving a good SWR reading and giving a false impression that all is well are very much more common than many people realise.
 

fisherman

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Perhaps it would make everyone happy if there were an automated system, we used to key the mike on the coast radio station channel, you got the carrier wave back for a few seconds as the equipment engaged. You could all agree a general chat channel (we use 8, scallopers use 14 etc etc) and do the job amongst yourselves, you could keep a dual watch with 16. In any case it's all a bit like opening a door to check it was really shut.

By the by my Shoreline Compact from 1992, on the aerial that was on the boat then is still good, while the other more expensive radio has been changed three times.
 

KellysEye

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>Testing with a handheld often means the signal doesn't go through the mast aerial at all - it's too close.

Don't check the main radio with a hand held on the boat, as you say it's too close. A quarter of a mile away is fine and obviously needs two people.
 

JumbleDuck

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In busy places I have the radio switched off nearly all the time

because of the pointless yack on 16

although up here in scotland it is often on listening to 16 just in case

The plague seems to have spread to the Clyde ... it was radio checks all day on Saturday. Perhaps it was just charterers setting out, but it was blinkin' annoying. Sunday was much quieter, mainly because I had the radio off.
 

ianfr

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Heard on Sunday as we returned to Tollebury

"Thames Coastguard this is yacht Something radio check please"
"Yacht something this is Thames Coastguard you are loud and clear on our Bradwell aerial" (2 - 3 Miles away)

30 Seconds later

"Yacht someone else this is yacht Something are you receiving?"
"Yacht Something this is Someone Else go channel 08"

Makes my head ache.

Ian
 

jimi

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Interestingly enough, I was fiddling with the radio at the weekend as I've had reception/transmission issues. The radio was receiving from the HH on the boat even without the coax plugged in. It was receiving from close by with the coax attached but no aerial.

My conclusion was that using the HH on the boat to test was irrelevant, using the quality of reception as a guide to transmission capability was equally irrelevant.
 

JumbleDuck

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Heard on Sunday as we returned to Tollebury

"Thames Coastguard this is yacht Something radio check please"
"Yacht something this is Thames Coastguard you are loud and clear on our Bradwell aerial" (2 - 3 Miles away)

30 Seconds later

"Yacht someone else this is yacht Something are you receiving?"
"Yacht Something this is Someone Else go channel 08"

Sounds as if Something couldn't raise his pal Someone Else, so he checked that his radio was working with the CG before trying again and his next call to Someone Else was answered.
 
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