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2014-08-05, 14:20
(This post was last modified: 2014-08-05, 14:22 by Mark.Smith.)
(2014-07-14, 23:54)Cutty Wrote: (2014-07-14, 23:36)MeteoCercal Wrote: For this type of problem (near high voltage power lines) what's the best system: H-Field or E-Field? It took me two months to find the one sweet spot in my garage, out of the entire dwelling, that the H field would work with good effect, consistently.
When I finished building it, I just chucked my H field amp up on a book case in my study to test it - worked brilliantly (and is still one of the better performing UK stations) I have only moved it to put some copper foil shielding on it :-) My E Field antenna is outside, mounted on an external wall, and can I get even a fraction of the performance out of it? can I heck...
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Given that a) nearest power line, 100 meters, is at 7.2KV, b) nearest big line is several miles away (115KV)...
What is the ideal system: H- or E- ?
We are in a LOW interference area. What are the advantages/disadvantages?
E-field is more sensitive?
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2014-08-20, 17:06
(This post was last modified: 2014-08-20, 17:10 by cutty.)
(2014-08-20, 16:15)billhoblit Wrote: Given that a) nearest power line, 100 meters, is at 7.2KV, b) nearest big line is several miles away (115KV)... No Problem
Quote:What is the ideal system: H- or E- ?
Both
Quote:We are in a LOW interference area. What are the advantages/disadvantages?
E-field is more sensitive?
First, remember that no station is a stand alone station. The system is a network concept. Stroke data required from several stations. Otherwise you have a nice set of flashing lights and a buzzer to tell you that 'something electromagnetic' hit the antenna / probe.
Some general very broad comments... Both have different characteristics and sensitivity to stroke parameters. Using both 5 channels of data vs 2 or 3. Possibility to expand stroke parameters with combo system (accuracy, type, polarity, etc). H field has slightly wider bandwidth.2 loop antennas, 2 channels. E field has very tight filtering, 3 bands, single E field probe 3 channels. E field less sensitive to H field Information and noise. E field 'simpler'--no fancy antenna...even a bottle cap can work. So sensitive that it's designed for shorter range, it could probably get signals from Jupiter if we could get VLF through the Ionosphere... long range generates many signals, therefore used for short range. H field generally for 'longer' range. Nearby cells more likely to induce 'interference' mode with H field. H field antennas in many cases can be inside. E field in most cases needs to be mounted outside well above ground, H field amp needs to be at antenna, with CAT5/6 shielded cable <10m to controller... E field amp can be right next to controller with Coax to the preamp/probe ... etc...etc...
Mike
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Ok, thanks. Remaining question: what is short vs. long range?
Short range: local strikes?
Long range: N.E. United States?
I'm located in N. Central Vermont, I'd like to capture the best quality data over longest range, but mostly want to fill any 'gaps' in coverage for the network.
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2014-08-20, 18:16
(This post was last modified: 2014-08-20, 20:44 by cutty.)
Bill...
Let's suggest 'short range' within 30 miles, medium range 30-300, and long range >300 miles, up to, let's say 3000 miles. Note that we'd like to function with only the ground wave components of the signals, with a range only of 30-80 miles or so, rather than with the reflected 'skywaves' that are distorted by the ionosphere. Note also that 'too many' signals will send your system into what we might call 'signal interference' mode... a 'variety' of the interference mode is 'burst' mode, where some repeating signal triggers interference for a brief time. In my experience, with my system, antennas, etc, I expect to go local interference on moderate to strong cells within 20-30 miles, using the H field antennas, and 10-20 with the E fields. This is part of the networking... if I go interference, the network covers the nearby strokes, until activity lessens, or storms move out of my area. I can drastically reduce my gains, for example, and operate in what I might call "local" mode, but that doesn't help the network. The network is designed to be extremely functional as stations go in and out of interference. Many of us in the US can 'crank up' and exceed 3500-4000miles... but the signals are practically useless, since other stations nearer have better quality signals. The system will use the best quality signals, so distance isn't really the issue with a network of reasonable station density. Meantime, I'll be pushing interference limits because of the activity in that 4000mi circumference and cluttering up the server and using my bandwidth with un-necessary data.
We have a lonesome single station in Hawaii that occasionally will nail a stroke or two in the Gulf of Mexico... so the system, properly optimized, with home built antennas has more than enough sensitivity but more of us in the US are dialing back to "Under 1200mi" since our stations are less needed in more distant areas, and our data may not even be selected for computation.
It's about locating accuracy, quality of signals...
Oh, forgot:
Most of the US operators hang out at http://www.wxforum.net/index.php?&board=115.0
Come join us, if you haven't found us yet...
Mike
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Just to chime-in here with a comment...
One of the first things new station owners seem to strive for is "max" distance of strike detections. As Mike has already said, it's not the distance that is important. It is the quality of the signals captured and sent to the network servers. If I look at my own statistics with my station being the only active station in Nevada, I will see my ratings on the lists rising and falling all the time. When storms are closer to me, my effectivity ratings rise and then drop when the storms are further away.
When I first came on-line about a year ago, I was disappointed that my effectivity numbers were so low. After some adjustments and getting to know how the system works, I soon realized that I really shouldn't care so much about the numbers but to be satisfied to know that, as a member of the overall network, I was contributing to the success of the system. Again, it's all about the collaboration of the signals coming in from everyone that makes this the great lightning detection system it is.
So, don't get hung-up on distance of strike detections. Instead, learn how to properly "adjust" your system so it contributes "quality" signals to the network.
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(2014-08-20, 17:24)billhoblit Wrote: I'm located in N. Central Vermont, I'd like to capture the best quality data over longest range, but mostly want to fill any 'gaps' in coverage for the network. Private messaging seems to be disabled, at least for me, so I'll clutter the forum with what could have been correspondence.
Where in Vermont are you billhoblit? I am just north of Burlington and hope to join the network soon with an H field receiver.
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