VK4WDM > 27-07-2018, 07:19 AM
VK4ADC > 27-07-2018, 08:06 AM
VK3RX > 27-07-2018, 08:42 AM
VK2CSW > 27-07-2018, 09:57 AM
VK4WDM > 27-07-2018, 11:43 AM
VK5TM > 27-07-2018, 01:42 PM
(27-07-2018, 11:43 AM)VK4WDM Wrote: The important question is: Given the ACMA inspectors rule that no wire antenna can be at a touchable height , will my elevated wire radials have to comply with that rule?
VK4WDM > 27-07-2018, 03:38 PM
VK5PJ > 27-07-2018, 04:37 PM
VK4WDM > 27-07-2018, 05:44 PM
(27-07-2018, 04:37 PM)VK5PJ Wrote: Hi Wayne
you also need to consider power levels in your planning. the vk3um EMR calc software is very handy for visualising the situation. I used this as a planning aid for a VHF high power permit application some years ago and learnt quite a bit from it during the process. I say this about power because an antenna is only a threat once it is enegised and the level of threat is dependant on the power level being used. I know most of the 1KW HP trial permit holders failed on EMR because parts of antennas were to 'exposed' to human contact. What that actually was I am unsure but using the VK3UM software you can see what exclusion zone it gives you for an antenna / power level combination and not rely on us bush laywers in forums :-)
Peter, vk5pj
VK2CSW > 27-07-2018, 06:01 PM
VK4WDM > 27-07-2018, 07:20 PM
VK2CSW > 28-07-2018, 08:18 AM
VK4WDM > 28-07-2018, 09:48 AM
(28-07-2018, 08:18 AM)VK2CSW Wrote: A question then, the answer for which I should know but I don't.
My meagre experience with ground plane antennas makes me think that there is very little energy in the ground plane. This comes from experience with mobile installations and a few 11m marine installations I have worked on.
If this is the case, what is the risk if someone touches the ground plane (radials in this case)?
If the risk can be shown to be negligible then I would think that the "rule" wouldn't apply.
BTW I occasionally run into a former field officer who lives somewhere locally, I'll run it past him next time I see him at the shops.
VK3RX > 28-07-2018, 10:23 AM
Quote:I think that "not touchable or reachable" means a radiating element not ground planes, radials or counter poises.
VK5TM > 28-07-2018, 11:14 AM
VK2CSW > 08-08-2018, 06:22 PM
VK4WDM > 08-08-2018, 08:55 PM
(08-08-2018, 06:22 PM)VK2CSW Wrote: I finally ran into the former Field Officer this morning. We had a rather wide ranging chat and I did remember to ask about "untouchable" antennas and "4m clearance".That sound's like good sensible and practical advice Colin! Might as well grow some tomatoes on the stakes. Will the RF make them bigger or smaller?
To put it simply, he knows of no such rulings. With the caveat that the description normally used is that the antennas must be inaccessible. To this point, I further asked if does having the antenna in your backyard, that has fences and gates, make it inaccessible. The reply was that without seeing the actual situation he couldn't be specific, but in general terms that would probably suffice.
The 4 metre thing, isn't a thing.
He did mention that they also take into account access by family, friends and other residents of the property - steps must be taken to protect them. Educating them is a valid protection.
I asked specifically about a ground mounted vertical, his suggestion was tomato stakes and electric fence tape. It really doesn't need to be a sturdy fence (assuming it is the secured backyard) it just has to be a barrier.
I hope this helps.
VK3RX > 09-08-2018, 10:31 AM
(08-08-2018, 08:55 PM)VK4WDM Wrote: [quote pid='2508' dateline='1533716533']
Will the RF make them bigger or smaller?
73
Wayne
VK5TM > 09-08-2018, 02:05 PM