Changes to VHF licence

[doug748]

Me too.

They should clearly mark all such stuff:

"Novice, Confused,Baffled ? - Panic not - this is merely an arse covering exercise"

 

[xyachtdave]

It's just Ofcom indulging in pointless box-ticking, and we're paying for it!

I wasted 30 seconds trying to fathom out what the email was trying to say, gave up, then deleted it.

 

[Alfie168]

I'm at least partly relieved that its not just me who was somewhat bamboozled by the letter. I found the calculator but for a 5w handheld and a 25 w VHF antenna at masthead I can't see a problem. It not like I have a radar array you can microwave a fried egg on.

I will have to read it all again..twice..but it seems remarkably unhelpfully drafted at first appraisal.

 

[st599]

I'm at least partly relieved that its not just me who was somewhat bamboozled by the letter. I found the calculator but for a 5w handheld and a 25 w VHF antenna at masthead I can't see a problem. It not like I have a radar array you can microwave a fried egg on.

I will have to read it all again..twice..but it seems remarkably unhelpfully drafted at first appraisal.

The figures you should be putting in to the calculator aren't 25 and 5, you need to factor in the antenna gain.

 

[Black Sheep]

PLEASE - can somebody who understands enough of it, and has the ability to communicate, draft an article for PBO etc.

Summarise what we need to do, and give some example figures for VHF (eg 25W into a normal masthead or pushpit antenna), AIS transmitter (I didn't know the 1/300 duty cycle figure), radar, active radar transponder.

(I hope PBO are already all over it.... and RYA and CA... but we need guidance)

 

[PhillM]

I’d say this could make an excellent article for one of the magazines. I’m sure that readership would treble if it could put in simple terms what this means for us all.

 

[ProDave]

I’d say this could make an excellent article for one of the magazines. I’m sure that readership would treble if it could put in simple terms what this means for us all.

Q: What does it mean for a VHF marine radio user?
A: Don't press the transmit button if anyone has climbed up to the top of your mast.

It really is that simple,

Is this some EU directive, if so WHY are we still wasting time on it?

 

[Alfie168]

The figures you should be putting in to the calculator aren't 25 and 5, you need to factor in the antenna gain.

I got as far as "limitations of the calculator" in the advisory notes, and decided they had omitted to mention the other major limitation. Me. I don't understand what the **** they are on about or what figures to put in and how to obtain a moderately accurate assessment. On the other hand...if my tiny installation is beyond the pale, then there is going to be a lot of Seelonce out there sometime soon !

 

[ithet]

Can I still put a microwave oven on board?

I suppose the ex- military tracking radar is out of the question now.?

 

[Black Sheep]

Q: What does it mean for a VHF marine radio user?
A: Don't press the transmit button if anyone has climbed up to the top of your mast.

It really is that simple,

Unfortunately it isn't.

 

[Thistle]

I used the calculator and got a "safe" distance of 1.1metres for the radar and 1.6metres for the 25w VHF. I guess it's just not a problem for mast-mounted antennas.

Agreed ... but I think I may have to grow longer arms to use my handheld.

 

[Alfie168]

Agreed ... but I think I may have to grow longer arms to use my handheld.

If thats euphemism then I might accuse you of bragging...

 

[Adios]

Is this some EU directive, if so WHY are we still wasting time on it?

I was just wondering that. Maybe, now that we've left the EU and no one from Brussels will be creating their living by making work for them any more they have to make the work for themselves and they are following the EU bureaucrats work creation method It will be a bit depressing if the spirit of the EU lingers.

 

[Badvisor]

Is this some EU directive, if so WHY are we still wasting time on it?

Yeah, the clue is EMF. Not sure what MF is but you can bet the E is for European

 

[john_morris_uk]

Yeah, the clue is EMF. Not sure what MF is but you can bet the E is for European

Golly. Talk about cynical and Europe.
No it doesn’t stand for European.
ElectroMagnetic Field. In other words the radiation field.

 

[st599]

Yeah, the clue is EMF. Not sure what MF is but you can bet the E is for European

Or Electromagnetic Field.

 

[lustyd]

Is this some EU directive, if so WHY are we still wasting time on it?

I hate to break it to you, but most of the really stupid EU stuff was proposed and voted for by the British.

 

[ProDave]

Unfortunately it isn't.

Why not?

The issue is to ensure you limit EM exposure to the public. Someone has already calculated with a 25W Marine transmission the safe distance is about 2 metres away from the aerial. Your aerial is at the top of your mast. Make sure nobody is up the mast before you press the PTT. Job done.

Now I will get on with sailing and put this silly directive at the back of my mind.

 

[st599]

The issue is to ensure you limit EM exposure to the public. Someone has already calculated with a 25W Marine transmission the safe distance is about 2 metres away from the aerial. Your aerial is at the top of your mast.

The public limit also affects all crew on board - occupational limits are for practitioners who know what they're doing.

The 25W calculation is wrong. The output of your power amplifier may be 25W, but the Effective Isotropic Radiated Power that the Ofcom spreadsheet needs isn't.

 

[st599]

The guidelines that Ofcom are telling us to implement are at: https://www.icnirp.org/cms/upload/publications/ICNIRPrfgdl2020.pdf
Figure 2 seems to be the main requirement. For those with Radar, the energy limit is higher at those frequencies so will need working out separately.

For a 5dBi antenna and a 25m run of RG58 @ 157MHz, I get an EIRP in the region of 56W, but I need to try and find a more accurate antenna spec sheet.