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Re: Heather Hall
Peter Day <microwaves@...>
Eddie G0EHV wrote:
Hello Peter,Away hinny! Way aye lad..
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rf hamdesgn 1.9m dish
John Randall <m0els@...>
Has anyone successfully recovered these dishes with a finer mesh, to
enable 10ghz to be used and what mesh diamter. Thanks John
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Re: Heather Hall
kenneth ferguson <ken_ferguson@...>
HEY I live up ere int north it be noys an hille wid sum gud seanry ewe suthen folk sud cum fer a visit an sea what ewe bea misin 8> ken ======================================== G0HYP IO84FN
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Re: Heather Hall
kenneth ferguson <ken_ferguson@...>
HEY I live up ere int north it be noys an hille wid sum gud seanry ewe suthen folk sud cum fer a visit an sea what ewe bea misin 8> ken ======================================== G0HYP IO84FN
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Re: Heather Hall
Eddie G0EHV
toggle quoted messageShow quoted text
----- Original Message -----
From: "Peter Day" <microwaves@blueyonder.co.uk> To: <ukmicrowaves@yahoogroups.com> Sent: Tuesday, April 18, 2006 11:18 PM Subject: Re: [ukmicrowaves] Heather Hall Ian Lamb wrote:Hello Peter,Andy, you wouldn't want to live up t'north would you????Nowt wrong wi' t'North tha naws.. Ah wuz born up 'ere o'coors. You're all Southerners to me! Regards, Eddie (On a very sunny Tyneside)
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Re: UKuG Microwave Contest 23, 13,9cm: Sunday 23 April 2006
Peter Day <microwaves@...>
g4bel wrote:
Hi All,Will do... many thanks Roger. Peter
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Re: ENV 50166-2
Graham Shirville <g.shirville@...>
Hi All,
Many many thanks to everyone who has provided the technical, ethical and
H&S etc answers to my question!
I now have more than enough data and information to enable me to complete
the form required at this stage and, as usual learnt a lot of information from
this group.
I am now well armed to provide any further answers needed when, hopefully,
we get the U/S transponder completed and when the integration takes place at the
ESTEC facility in the Netherlands, and eventually, when pre-flight testing is
undertaken at the launch facility in Kourou in French Guiana.
I greatly appreciate your help!
73
Graham G3VZV
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Risk
Steve Bunting M0BPQ
Reg Wrote
"Am I right in assuming not any old Tom, Dick or harry can write one. Unless you have done a course on how to structure etc. Then your not deemed a competent person to do so? Reg G8VHI" The issue here, Reg, is "Will a risk assessment done by a untrained person stand up in court should litigation start?" Most organizations' chief execs (who are now legally responsible for H&S) will answer "no" to that and therefore insist that people are trained. Training reduces the risk of a incorrect assessment! In the environment that Graham is working I would be amazed if no-one is responsible for H&S and able advise on document format etc. However, Graham may not be able to pass the buck as the designated H&S person often consults a local procedural or technical expert to fill in gaps in his/her knowledge. I agree 100% with others that there is no legal substitute for measurement and compliance with standards, no matter how daft you think they are. Just be thankful that you don't have to get ethical approval for projects - that is a minefield in itself so don't get me started :-) 73 Steve
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Re: ENV 50166-2
Mark GM4ISM <gm4ism@...>
The issue of competency is probably the biggest issue here.
Almost any adult can be deemed a competent person for the purpose
of carrying out low level tasks with instructions.
To do a risk assessment may not require formal training, but someone with
appropriate responsibility has to determine that the individual doing
the assessment is competent to do it. This decision would probably also be
recorded!
In this case, a person involved with the technical aspects of the
activity, with the relevant experience / training / knowledge of the
hazard, and knowledge of any risk assessment protocols used in the organisation
may be deemed competent.
Its a minefield!
Mark GM4ISM
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Re: ENV 50166-2
Mark GM4ISM <gm4ism@...>
Gents,
Chris and Andy are both essentially right, but a
couple of other points need to be raised.
The use of a calibrated hazard meter is essential
for an assessment of the safety of the work environment, they can be hired from
test gear suppliers like microlease and others (I have a few contacts of
companies I have hired them from in the past, please contact me off
list)
To reduce the chance of litigation, a risk
assessment needs to be formally recorded and performed by a person
competent to do it. You will get extremely high readings on an e-field probe
like an EMR300 when in close proximity to the antenna. There is
no RF meter on the market that can accurately assess near field
levels (within a few wavelengths of the antenna)
The people working on the project need to be aware
of the hazard and any control measures taken to reduce risk. The transmitter
power is low. Even at a small distance the most pessimistic analysis to
show field less than the levels indicated by current legislation. That is not
including time averaging, which is a road I would not go down. The prescribed
levels are not limits but if you treat them so you will be well on the side of
safety.
My main concern is that someone could get their
eyes significantly closer to the radiating element while the transmitter is on,
and at the power levels indicated there is a small but finite risk of eye
damage.. The eye cannot dissipate heat energy very well.
Possible control measures
Physically restricting approach to the antennas to
a safe distance is probably best, though you may consider having a bright light
next to the antenna that is on when the transmitter is running, to warn
'trained' personnel to keep their heads away.
The actual risk from this scenario seems to be
quite low, but that risk assessment does need to be done properly, and to be
seen to be done properly.
Again, please contact me off list, I may be able to
help with informal or formal advice.
regards
Mark
GM4ISM
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UKuG Microwave Contest 23, 13,9cm: Sunday 23 April 2006
g4bel <RogerTaylor@...>
Hi All,
I should be on from home for most of the event, so please add me to your list Peter. G4BEL JO02BI Cambridge 23cm 300w 1.5m dish 13cm 60w 1.5m dish 9cm 50w 70cm dish. 73 Roger
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ENV 50166-2
Chris Bartram <yahoo@...>
Do a simple back of envelope calculation first to get a ROM estimate, then if At 1 metre distance, area of a sphere = 4.pi.r^2 = 12.5m^2 You haven't stated the gain of the antennas, but lets say 5dBi (quad helix, Which is way below the 5mW/cm^2 nanny-state-imposed safety limit. And with that margin, I don't think anyone in their right mind - even aI couldn't dispute Andy's argument in a free-space environment, but in an indoor environment, you also have to factor-in reflections, which can cause large variations in field strength. Incidentally, the current HPA exposure standard for amateur radio applications above 23cm is 10W/m^2 (1mW/cm^2) averaged over 6min, so there's not that big a margin in Andy's estimate... If you are exposing people to radiation, you have a legal duty of care to ensure that they are not exposed to levels above the statutory limits. A back-of-envelope calculation would probably not be seen as adequate by a Court... Systematic measurement with a calibrated instrument would be. I guess that Andy and I have different attitudes wrt Health and Safety: I could get sued if I get things wrong, I suspect Andy works under Crown Immunity!! Vy 73 Chris GW4DGU
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Re: UKuG Microwave Contest 23, 13,9cm: Sunday 23 April 2006
Sean <m1ecy@...>
Hi All,
I will be working till 5pm, but will be happy to join in when I can - At present only QRP on 23 cm from home - 10W to 4x23ele - I doubt the PA will be ready by then...... Cheers Sean M1ECY --- In ukmicrowaves@yahoogroups.com, Peter Day <microwaves@...> wrote: ........................................................................................................... (Dave) 1.3 GHz - 250W into 4 x 35 element
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Cloverleaf
Chris Bartram <yahoo@...>
A member of our Club(MIDCARS) is trying to find information about a Clover G8ATBSomewhere in my junk boxes I have a 23cm clover leaf which I made in the 1980s for mobile use. It worked surprisingly well. If your friend can't find the VHF Comms article, I'd be happy to lend it to him so he can copy it. Vy 73 Chris GW4DGU
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UKuG Microwave Contest 23, 13,9cm: Sunday 23 April 2006
Peter Day <microwaves@...>
Hello folks,
It's now the time to dust off the microwave gear that you've not been using since last October! The UK Microwave Group's first contest of 2006 takes place this coming Sunday, 23rd April with the Low Band Contest on 23, 13 and 9cm... scheduled from 0900GMT to 2000GMT. Please try to come on if only for a short time. The portable stations in particular would welcome contacts to justifiy the effort made to get out on what might be a cold and rainy day! Proposed activity reported to me so far is shown below. If you wish to be on this list then let me know before Friday lunchtime as the last version of this activity list will be emailed around my list on late Friday evening. Some of you may receive this twice if you get a direct version as well as the one on the UKuG Microwave Reflector. ........................................................................................................... UK MICROWAVE GROUP LOWBAND (23/13/9cm) CONTEST SUNDAY 23 APRIL 2006 ------------------------------------------------------------------- G3PHO/P:Either Yorkshire Wolds (IO93PW37) or Blakey Ridge, North York Moors (IO94MI) (depends on how early I can get out of bed!) Active from 0900-1800GMT. 23cm: 18W to a 23 element Tonna 9cm: 16W to a 1.2m dish 13cm: Not available 144.175MHz ssb Talkback Mobile phone: 07811 808605 KST: Only last resort... need another pair of hands for this! G0DPS/P:Oxenhope Moor, IO93FL12 23cm: 10 watts to 4 by 36 ele long yagis, about 433 mtrs asl G8ACE: Unlikely to be /p now so operation from home at IO91IB. 9cm and 23cm bands. G1EHF/P:IO80WP (Whiteways Hill on the Purbecks) Operators:G3TCU (Phil), G4SJH (Barry), G3TCT (Graham) and G1EHF (Dave) 1.3 GHz - 250W into 4 x 35 element 2.3 GHz - 10W into 25 element 3.4 GHz - 10W into 0.8m offset dish Talkback: 144.175MHz and ON4KST 2E0CDJ: IO71XT Home station. 23cm: 10W to 2 x 35ele Tonnas 655ft asl. (Welcome to the UK Microwave Group Daran !) G4RFR/P:I080??: Flight RTefuelling HQ Wimborne, Dorset M0EYT and G0NZO and possibly some other local microwavers are planning to install 23, 13 and 9cm on the mast up at the FRARS HQ. Talk back: 144.175MHz ssb and KST r... G3XDY: JO02OB Home station. 1.3GHz 200W to 4 x 23ele Yagis 2.3GHz 120W to 0.8m dish 3.4GHz 20W to 0.6m dish ON4KST and 144.175MHz for talkback, but mostly CQing around 1296.213MHz.
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Re: Clover Leaf attena
Jonathan Naylor <naylorjs@...>
I am sure that there was a clover leaf antenna design in the 1970s
vintage VHF Manual from the ARRL. Jonathan ON/G4KLX
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Re: Clover Leaf attena
Chris G8BKE
VHF Comms 4/1979 has a 23cms Big Wheel (clover leaf?) antenna article in it by DD0QT..do you want a
copy? 73 de Chris G8BKE Web Site:- http://www.qsl.net/g8bke/index.html Hi all A member of our Club(MIDCARS) is trying to find information about a Clover Leaf antenna for 23Cms he built a few years ago form articles in VHF Comms - has anybody got a copy of the articles or any further information please. G8ATB "Many years ago I was given a article for a Clover leaf and 4ele beam for 1296 to use with a Microwave converter. I see from this VHF Comms site that two articles are listed DD0OT 1973/2 page 110-115 Clover leaf. DC8XB 1980/1 page 203-207 4ele beam."
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Re: Clover Leaf attena
Andy Rutter, G8HCK
G3at@aol.com wrote:
Hi all I don't have 1973/2, but there is no reference to the Clover Leaf article in the 1973 index. I do have 1979/4 which has 'Big Wheel - An Omnidirectional Antenna for the 23cm Band' by DD0QT. Could this be the article you need? I think your VHF Comms references are a little awry - the 4 ele beam article by DC8XB is actually 1971/3 pg 132-133 - or maybe these are not from the UK version. -- Andy, g8hck
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Re: ENV 50166-2
regwoolley@...
In a message dated 19/04/2006 13:54:50 GMT Standard Time,
gm4ism@... writes:
Am I right in assuming not any old Tom, Dick or harry can write one. Unless
you have done a course on how to structure etc. Then your not deemed a competent
person to do so? Reg G8VHI
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Re: ENV 50166-2
Mark GM4ISM <gm4ism@...>
Gents,
Chris and Andy are both essentially right, but a
couple of other points need to be raised.
The use of a calibrated hazard meter is essential
for an assessment of the safety of the work environment, they can be hired from
test gear suppliers like microlease and others (I have a few contacts of
companies I have hired them from in the past, please contact me off
list)
To reduce the chance of litigation, the risk
assessment needs to be formally recorded and performed by a person
competent to do it. You will get extremely high readings on an e-field probe
like an EMR300 when in close proximity to the antenna. There is
no RF meter on the market that can accurately assess near field
levels (within a few wavelengths of the antenna)
The people working on the project need to be aware
of the hazard and any control measures taken to reduce risk. The transmitter
power is low. Even at a small distance the most pessimistic analysis to
show field less than the levels indicated by current legislation. That is not
including time averaging, which is a road I would not go down. The prescribed
levels are not limits but if you treat them so you will be well on the side of
safety.
My main concern is that someone could get their
eyes significantly closer to the radiating element while the transmitter is on,
and at the power levels indicated there is a small but finite risk of eye
damage.. The eye cannot dissipate heat energy very well.
Possible control measures
Physically restricting approach to the antennas to
a safe distance is probably best, though you may consider having a bright light
next to the antenna that is on when the transmitter is running, to warn
'trained' personnel to keep their heads away.
The actual risk from this scenario seems to be
quite low, but that risk assessment does need to be done properly, and to be
seen to be done properly.
Again, please contact me off list, I may be able to
help with informal or formal advice.
regards
Mark
GM4ISM
----- Original Message -----
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