Topic: Potential New User Questions

[Steve2q]

Hello all. I have had the Blitzortung web site linked to my weather station site for quite some time, and now I am thinking of setting up a receiving station (Blue). I am a ham radio operator (N2QLQ), and I have some questions that the answers may make or break my going ahead.

1. This is a question for other hams: from my reading the forums, it seems like the two different antennas are relatively insensitive to frequencies > 1.8MHz. Is this true? Is one type better than the other in this regard? My HF antenna (I run < 100 watts) is a "stealth" dipole in the attic.

2. I live in a "antenna restricted" development. If I choose to use the antenna that is mounted outside, how large is it? I did get permission to put up my weather station components, so I can just say that the antenna is part of it and has always been there! 

Thanks, Steve

[Cutty Sark Sailor]

E field probe... my two systems use a 35mm and 15mm respectively. A metal pop bottle cap will work fine.
H field: My Red uses 2 homewound  300mm x 7.5mm ferrites @ 90°. Blue development 3 DELTA (60°) 250mm X 7.5 mm ferrites..
Operators use every imaginable kind of loop, from 12" Balls, to 5 Feet coax loop, Mobius, etc... Antennas are unturned.
Our spectrum of interest is generally 3-30lHZ where most impulse energy resides...
BLUE Systems have "functional" bandwidth up to ± 300kHz, filter restrictions are in preamps, and amplifiers...(BLUE has optional electronic filters) not necessarily 'antenna design'... in addition to trigger settings etc... just don't want antennas that induce long delay times.
Hams have had little issue running BT and Ham ... our issues are robot mowers, pet fences, light dimmers, plasma TV's street lights, auto ignition, computers too near, cheap-a**ed power supplies, solar power systems... blah, blah, blah....

It some respects, I still say  it may be simpler, at times, to think of BT as wideband "audio" impulse processing, rather than "RF".... In other words, if it bleeds your audio system, it'll bleed Blitzortung... now, here's where the usual or unusual few will jump in to tell me I don't know what the hell I'm talking about...   

[miraculon]

I have my ferrite antennas mounted on a box on an inside garage wall. My 1m loop antennas on my RED and the E-field is in my garage rafters.
In my previous house I had the Green with the ferrites mounted in an upstairs bedroom closet.
The GPS antennas are located outside, however.
My Boltek detector is affected by my 2 meter rig, but the Blitzortung isn't. Keep in mind that the Boltek is much closer to the 2m antenna.

73
Greg KE8DAF

[dfroula]

Hi, Steve.

I have my two homebrew ferrite antennas in an attic. but only because it is the spot in the house farthest from interference sources. The antennas work equally well in my sub-basement, except for the local noise from the DC furnace blower motor and other stuff I have there.

As Mike said, the E-Field antenna can be made quite small. However, there is a requirement that it be outside and a minimum distance above ground for best performance, I have my preamp board and 6-inch wire antenna sealed in a PVC radome and mounted above my TV antenna on the roof, near my ADS-B radar antenna. It works extremely well in that location.

Regarding system bandwidth, the filters are quite selective, but any nearby HF/VHF transmitting gear of significant power (over a few hundred milliwatts) will likely get into the system unless great care is taken with system shielding. Most of us have our units in plastic boxes or sitting bare on a piece of plywood. The worst issues to solve are near-field inductive/capacitive coupled harmonic distortion noise from non-linear AC line loads, like switching power supplies and motor drive circuits.

Best regards,

Don F.
WD9DMP

PS - Audio processing, eh Mike!!!!?????