On 15 Oct, 00:46, MB <M...@invalid.invalid> wrote:

> Dychliemore has them on the same small lattice tower.

I wonder what filters are on that?

If they were originally lazy, and used a single bandpass for the
entire group (unlikely), that would be nicely re-broadcasting digital
already!

I'm guessing they're individual channelised filters, so no digital.

Cheers,
David.

In message , Dave 
Liquorice  writes
>On Fri, 16 Oct 2009 11:35:46 +0100, Paul Martin wrote:
>
>>> It has long been my contention that the huge Meadowhall Shopping
>Centre
>>>  sells nothing of use to Man.
>>
>> Is there anything of use to Woman? :-)
>
>They seem to think so. Plenty of shoe shops but why do you need more
>than a pair of wellies, a pair of walking boots, a pair of shoes and
>pair of slippers?

Thank you!   I'm always telling Louise that but she doesn't seem to 
agree.

However, it was a client of mine who once went on a four day trip to 
Belgium I managed who took *two* suitcases.   One for her clothes and 
the other for the **28** pairs of shoes she took with her!

Ironically, none of these 28 pairs was in the least suitable for walking 
on the tours around the cobbled streets of Bruges of Ghent.

So yes, presumably all these show shops do serve a purpose.

Interestingly, I suspect that no one in any of them would have 
understood what an attenuator was.   Nor a single frequency network. 
Nor a Multiplex.   Nor what SCART actually means.

Funny world.......

(Sorry to rabbit on.   I'm stuck in waiting for a tree surgeon to 
arrive.)
-- 
Ian Jelf, MITG
Birmingham, UK

Registered Blue Badge Tourist Guide for London and the Heart of England
http://www.bluebadge.demon.co.uk

Now blogging in "The World According to Ian Jelf" at
http://ianjelf.blogspot.com

[added x-post to uk.tech.broadcast - thanks for the suggestion Bill]

Andy Dee wrote:
> Lobster wrote:
>> Sorry for the OT post but would really appreciate the advice,and I 
>> know people here will have the answer...
>>
>> I've just received a text message from a friend who's working in the 
>> Middle East today doing repair work on big radio masts.  He's just 
>> been sent 50m up a mast with live microwaves (for mobile phones), with 
>> VHF radio transmission for TV and radio on the same mast 50m above 
>> that; having been assured it was perfectly safe to do so but has 
>> subsequently found out that this was pure supposition.  Ha bloody ha.
>>
>> Understandably he's now very worried and upset. He's asked me to find 
>> out anything I can about UK guidelines, radiation risks etc; what he's 
>> likely to have done to himself and if there's anything he can do now?
>> Apparently this is a main mast for the whole country so presumably 
>> it's going to be pretty powerful.
>>
>> If anybody could point me at some guidelines or has any helpful advice 
>> I can relay back to him urgently I'd be really grateful. Anything else 
>> I need to ask him?

> No-one here can say if that was safe or not.
> 
> If he was 50m below the main VHF aerials, then there is no need to 
> worry. Field strengths directly behind these would certainly be higher 
> than that which is considered to be safe, although some are adequately 
> screened so that one is able to climb through safely but not linger there.
> Cellphone panels have little radiation back towards the mast. The powers 
> are also much lower than broadcast. As long as he was not in front of 
> these panels, then there is little risk. Same goes for dishes.
> Cellphone antennas using "co-linears" (an omni-directional vertical) are 
> renowned for high field strengths but that doesn't extend far above and 
> below.
> 
> Physical exposure to high levels of non-ionising radiation causes the 
> body to heat-up so hopefully, he didn't notice anything like this whilst 
>  on the structure.
> 
> HSE publishes exposure limits but unless a hazard meter is available, 
> this cannot be checked.
> 
> In the UK, each mast has a safety survey which shows the field strengths 
> and lists the measures to be taken when work is to be carried out at 
> each height.
> 
> If your friend is a trained rigger, he should know all this anyway. If 
> he is not, then what is he doing working on transmitter masts?

Many thanks for that advice Andy, much appreciated: sounds reasonably 
encouraging.

He's a trained rope-worker for sure, whether that normally covers 
transmitter masts I have no idea - but pretty sure this is the first 
time he's been asked to work on one, anyway. But God knows what rules 
and regs apply in the country he's working in :-(  Wouldn't be my first 
choice of employer/employment, that's for sure...

Any further comments from anyone much appreciated.

David

Lobster wrote:
> [added x-post to uk.tech.broadcast - thanks for the suggestion Bill]
> 
> Andy Dee wrote:
>> Lobster wrote:
>>> Sorry for the OT post but would really appreciate the advice,and I 
>>> know people here will have the answer...
>>>
>>> I've just received a text message from a friend who's working in the 
>>> Middle East today doing repair work on big radio masts.  He's just 
>>> been sent 50m up a mast with live microwaves (for mobile phones), 
>>> with VHF radio transmission for TV and radio on the same mast 50m 
>>> above that; having been assured it was perfectly safe to do so but 
>>> has subsequently found out that this was pure supposition.  Ha bloody 
>>> ha.
>>>
>>> Understandably he's now very worried and upset. He's asked me to find 
>>> out anything I can about UK guidelines, radiation risks etc; what 
>>> he's likely to have done to himself and if there's anything he can do 
>>> now?
>>> Apparently this is a main mast for the whole country so presumably 
>>> it's going to be pretty powerful.
>>>
>>> If anybody could point me at some guidelines or has any helpful 
>>> advice I can relay back to him urgently I'd be really grateful. 
>>> Anything else I need to ask him?
> 
>> No-one here can say if that was safe or not.
>>
>> If he was 50m below the main VHF aerials, then there is no need to 
>> worry. Field strengths directly behind these would certainly be higher 
>> than that which is considered to be safe, although some are adequately 
>> screened so that one is able to climb through safely but not linger 
>> there.
>> Cellphone panels have little radiation back towards the mast. The 
>> powers are also much lower than broadcast. As long as he was not in 
>> front of these panels, then there is little risk. Same goes for dishes.
>> Cellphone antennas using "co-linears" (an omni-directional vertical) 
>> are renowned for high field strengths but that doesn't extend far 
>> above and below.
>>
>> Physical exposure to high levels of non-ionising radiation causes the 
>> body to heat-up so hopefully, he didn't notice anything like this 
>> whilst  on the structure.
>>
>> HSE publishes exposure limits but unless a hazard meter is available, 
>> this cannot be checked.
>>
>> In the UK, each mast has a safety survey which shows the field 
>> strengths and lists the measures to be taken when work is to be 
>> carried out at each height.
>>
>> If your friend is a trained rigger, he should know all this anyway. If 
>> he is not, then what is he doing working on transmitter masts?
> 
> Many thanks for that advice Andy, much appreciated: sounds reasonably 
> encouraging.
> 
> He's a trained rope-worker for sure, whether that normally covers 
> transmitter masts I have no idea - but pretty sure this is the first 
> time he's been asked to work on one, anyway. But God knows what rules 
> and regs apply in the country he's working in :-(  Wouldn't be my first 
> choice of employer/employment, that's for sure...
> 
> Any further comments from anyone much appreciated.
> 
> David
> 

For future reference, the first signs that you are being irradiated is 
usually tingling in the ears, and as others have said if he was behind 
the antennae he was probably safe, in front of them NOT. most are highly 
directional to ensure they get max range.

Vernon wrote:

> For future reference, the first signs that you are being irradiated is 
> usually tingling in the ears, and as others have said if he was behind 
> the antennae he was probably safe, in front of them NOT. most are highly 
> directional to ensure they get max range.

As a licensed radio ham, I have to ask the question of 'why the tingling 
in the ears?'


Dave

The message <SvKBm.57476$ly7.6269@newsfe14.ams2>
from Lobster  contains these words:

> [added x-post to uk.tech.broadcast - thanks for the suggestion Bill]

> Andy Dee wrote:
> > Lobster wrote:
> >> Sorry for the OT post but would really appreciate the advice,and I 
> >> know people here will have the answer...
> >>
> >> I've just received a text message from a friend who's working in the 
> >> Middle East today doing repair work on big radio masts.  He's just 
> >> been sent 50m up a mast with live microwaves (for mobile phones), with 
> >> VHF radio transmission for TV and radio on the same mast 50m above 
> >> that; having been assured it was perfectly safe to do so but has 
> >> subsequently found out that this was pure supposition.  Ha bloody ha.
> >>
> >> Understandably he's now very worried and upset. He's asked me to find 
> >> out anything I can about UK guidelines, radiation risks etc; what he's 
> >> likely to have done to himself and if there's anything he can do now?
> >> Apparently this is a main mast for the whole country so presumably 
> >> it's going to be pretty powerful.
> >>
> >> If anybody could point me at some guidelines or has any helpful advice 
> >> I can relay back to him urgently I'd be really grateful. Anything else 
> >> I need to ask him?

> > No-one here can say if that was safe or not.
> > 
> > If he was 50m below the main VHF aerials, then there is no need to 
> > worry. Field strengths directly behind these would certainly be higher 
> > than that which is considered to be safe, although some are adequately 
> > screened so that one is able to climb through safely but not linger there.
> > Cellphone panels have little radiation back towards the mast. The powers 
> > are also much lower than broadcast. As long as he was not in front of 
> > these panels, then there is little risk. Same goes for dishes.
> > Cellphone antennas using "co-linears" (an omni-directional vertical) are 
> > renowned for high field strengths but that doesn't extend far above and 
> > below.
> > 
> > Physical exposure to high levels of non-ionising radiation causes the 
> > body to heat-up so hopefully, he didn't notice anything like this whilst 
> >  on the structure.
> > 
> > HSE publishes exposure limits but unless a hazard meter is available, 
> > this cannot be checked.
> > 
> > In the UK, each mast has a safety survey which shows the field strengths 
> > and lists the measures to be taken when work is to be carried out at 
> > each height.
> > 
> > If your friend is a trained rigger, he should know all this anyway. If 
> > he is not, then what is he doing working on transmitter masts?

> Many thanks for that advice Andy, much appreciated: sounds reasonably 
> encouraging.

> He's a trained rope-worker for sure, whether that normally covers 
> transmitter masts I have no idea - but pretty sure this is the first 
> time he's been asked to work on one, anyway. But God knows what rules 
> and regs apply in the country he's working in :-(  Wouldn't be my first 
> choice of employer/employment, that's for sure...

> Any further comments from anyone much appreciated.

> David




I would think of rope workers as the people you see working on rockfaces
at the side of the road.  Working on transmission masts requires
different skills, training and procedures.  If he is worried then it
sounds as if he has received no training on working near RF so I would
be very suspicious of the safety procedures of the company he is working
for.

Apart from procedures and surveys of the tower, there should also be
some sort of calibrated instrument for checking RF levels.  The
procedures are important because they have been cases where someone has
switched things back on whilst riggers have been in a danger area so
there needs to be procedures to stop this happens and also othe
procedures to get them switched off immediately if someone ignores the
rules.

"MB" <MB@invalid.invalid> wrote in message 
news:31303030303731354AD7967841@invalid.invalid...
>> He's a trained rope-worker for sure, whether that normally covers
>> transmitter masts I have no idea - but pretty sure this is the first
>> time he's been asked to work on one, anyway. But God knows what rules
>> and regs apply in the country he's working in :-(  Wouldn't be my first
>> choice of employer/employment, that's for sure...
>
>> Any further comments from anyone much appreciated.
>
>> David
>
> I would think of rope workers as the people you see working on rockfaces
> at the side of the road.  Working on transmission masts requires
> different skills, training and procedures.  If he is worried then it
> sounds as if he has received no training on working near RF so I would
> be very suspicious of the safety procedures of the company he is working
> for.

Thanks MB, you've given me the excuse to post this that I found
mildly amusing at the time I saw it.
http://myweb.tiscali.co.uk/infoweb/laddervan.jpg


-- 
Graham.

%Profound_observation%

"Lobster"  wrote in message 
news:SvKBm.57476$ly7.6269@newsfe14.ams2...
> [added x-post to uk.tech.broadcast - thanks for the suggestion Bill]
>
> Andy Dee wrote:
>>> Understandably he's now very worried and upset. He's asked me to find 
>>> out anything I can about UK guidelines, radiation risks etc; what he's 
>>> likely to have done to himself and if there's anything he can do now?

So far I don't think we've had a response covering the future symptoms that 
might develop. If he endured the exposure without being aware of any ill 
effects, does that mean there will be no future problems?

Bill

"Andrew Gabriel"  wrote in message 
news:hbc3i2$3ks$2@news.eternal-september.org...
> In article ,
> "Bill Wright"  writes:
>>
>> "Lobster"  wrote in message
>> news:SvKBm.57476$ly7.6269@newsfe14.ams2...
>>> [added x-post to uk.tech.broadcast - thanks for the suggestion Bill]
>>>
>>> Andy Dee wrote:
>>>>> Understandably he's now very worried and upset. He's asked me to find
>>>>> out anything I can about UK guidelines, radiation risks etc; what he's
>>>>> likely to have done to himself and if there's anything he can do now?
>>
>> So far I don't think we've had a response covering the future symptoms 
>> that
>> might develop. If he endured the exposure without being aware of any ill
>> effects, does that mean there will be no future problems?
>
> Certain body organs are particularly susceptable to damage from
> even a small amount of radiation induced heating and/or their
> composition makes them more susceptable to absorb the energy.
> Lenses in the eye form cataracts, but I believe that's pretty
> instant (same effect as cooking egg white).
> Kidneys are another, but it can take you a few days to realise
> kidneys have stopped working (or even longer if they haven't
> completely stopped). Also depends on the wavelength, at what
> depth below the skin the heating effect takes place.
>

All those effects are from direct RF heating tissue.  Fortunately for the 
OP's friend the levels required to do damage are actually quite high.  Most 
wavelengths are either reflected by flesh (water), and of the transmitted 
power into the body, it's quickly absorbed.  I wasn't aware that cataracts 
formed so quickly.  One would have thought more cataracts would be formed by 
standing close to fires.

My instinct does suggest that working behind mobile radio aerials would pose 
little danger, the maximum power emitted would be in the region of 30W 
forward.  As long as he stayed within the confines of the mast, I doubt 
there would be much power in the VHF band, especially 50m away from those 
aerial.

I would say that he ought to take more care though, and only climb a mast 
which has been surveyed for field strength.  It seems this one hadn't?