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E field antenna height - Printable Version

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E field antenna height - DrRobin - 2016-09-27

Hi,

I have just received my system blue and going to make E field and H field antennas.  I have a couple of questions:

What is the minimum height for the E field antenna?
If I mount the system blue in my shed then I doubt I can get the E field antenna above 5m.
If I put the E field antenna in my house the E field antenna will have to go on my wind speed/direction mast, the wx station transmitter is located about 4m below, will this be okay as the speed/direction is just low frequency switch contacts?

The H field antenna is going to be two ferrite rod antennas, these will probably be in the loft.  I assume that these are both mounted horizontally, one facing east-west and the other north-south?

If I put my system blue in a remote location and use a wifi router what is the minimum recommended distance from system blue to wifi?

Sorry for the stupid basic questions but I would like to get it installed in the best place first time.

Thanks

Robin

RE: E field antenna height - RichoAnd - 2016-09-27

There is no lower limit for the height of the E-field antenna - If the antenna stood far out on a grassy field, it might be a few cm above grass height.
If it is to be able to "see" far omnidirectionelt, it should be just above the highest point (ideally)
At the top of a mast is very fine, but it may also be a piece down the mast - If metal mast, do a space of 10-15 cm from antenna to mast.

Do not compare the E-field antenna with a radio/television antenna, which can only see just over the horizon. E-field signals are more tolerent.

An electronic weather station sends pulses and not only DC signals. Although these are at a low frequency, the switches can generate interfering signals.
You can create a temporary setup where the antenna comes near the anemometer and wind direction indicator to check it out, before you set it up permanently.

Ferrite antennas in a horizontal cross on the ceiling is really good as long as they are kept as far away from electrical installations (preferably more than two meters)
It need not be NS / EW but it is practical to do so.

Distance between WiFi units depends on the situation - you can not not say anything specific about that.
It is not difficult to test, because BLUE just need 5 volts to operate, so it is easy to move around during the test.

/Richo

RE: E field antenna height - Ranieri - 2016-09-28

I can mount two ferrite antenna and an E-field antenna in TV antenna pole?
if you are a good location?

RE: E field antenna height - RichoAnd - 2016-09-28

Yes, it's a good position

/Richo

RE: E field antenna height - Ranieri - 2016-09-28

Thanks Richo.
It is better to put in different places (distant) antennas in ferrire and E-field antenna?

RE: E field antenna height - RichoAnd - 2016-09-29

They can be in the same box if you like

RE: E field antenna height - vk2him - 2017-11-04

Does the E-field antenna need to be a certain height above a metal roof?
Will the ferrite antenna be attenuated if placed in the loft which has a metal roof?
Thanks
Ian

RE: E field antenna height - RichoAnd - 2017-11-04

E-Field need to be outside - works if it's just over the roof. BUT it must be free from mains and other disturbances.
H-Field is pure magnetic, and since it's hard to screen magnetic fields, it works under a metal roof.

I would give ferrite antennas at least 10 cm from metal and loops at least 50cm
Metal roof should not be connected electrically to pre-amps, but may be grounded

/Richo

RE: E field antenna height - RichoAnd - 2017-11-04

doubble post :-(

RE: E field antenna height - vk2him - 2017-11-04

Thanks Richo for this excellent information ... I operate an amateur radio station at home operating mainly on the 2M band @ 145.175Mhz with 40W - do you think this will cause an issue? I plan to place the e & h antenna as far as possible from the 2m antenna. 

I also have solar panels with micro-inverters that communicate over the internal electrical wiring - have you heard of issues caused by power line communications?

My System Blue was posted the other day so I'm getting myself organised in advance.

Regards
Ian

RE: E field antenna height - Benedict.Smith - 2017-11-04

(2017-11-04, 08:26)vk2him Wrote: Thanks Richo for this excellent information ... I operate an amateur radio station at home operating mainly on the 2M band @ 145.175Mhz with 40W - do you think this will cause an issue? I plan to place the e & h antenna as far as possible from the 2m antenna. 

I also have solar panels with micro-inverters that communicate over the internal electrical wiring - have you heard of issues caused by power line communications?

My System Blue was posted the other day so I'm getting myself organised in advance.

Regards
Ian
Ian, I used to use Ethernet over power adapters before I had a Blitzortung station, they caused huge amounts of RF noise across a wide spectrum and one of the first things I did was to give them away to someone who lived a good distance from me, I wouldn’t touch them again, I think a lot of radio amateurs have similar views on them.
I have also read of noise problems with solar inverters but don’t have any myself so cannot comment further.