Hello John,

The following page on the google groups has a lot of links on WWVB:
https://groups.google.com/forum/#!topic/rec.radio.amateur.antenna/A2CHeHadcCM

Bertus

 

Hello John,

I had a look at the files on my harddisk and found a PDF about a dedicated loop antenna for WWVB.
(I have to many files on my disk, about 23 Gb on electronics stuff).

Bertus

 

Thank you for thinking of this thread. That is the exact procedure I followed. Here's the link I used: http://www.febo.com/time-freq/wwvb/antenna/ I did come up with a 1000 pF variable air capacitor that made tuning easier. 23,100 pF is what I ended up with for tuning.

The darn thing works good, too good for today's plans. Last week, I had problems with noise from late morning to late afternoon (WWVB at Fort Collins ,CO is -2 hours relative to me). I worked on a digital noise filter (described in another AAC thread in microcontrollers) and was waiting for the same type of noise today to refine the sampling interval. There has not been a blip. (The oscilloscope tracings I show in the other thread result for some local and short-term interference I occasionally see, not the more predictable daily occurrence. We are just having very good, high-pressure weather.)

John

 

Hello,

Did you ever see this old thread?
http://forum.allaboutcircuits.com/t...gn-40khz-jjy-60khz-wwvb-75-5khz-dcf77.101544/

Bertus

 

Thanks, Bertus. I had not seen that old thread. That is basically the "receiver" I made with the 2N3819 input and TI081 (or newer version) op-amp.

The "problem" I am having now is getting some natural noise to test my filter. We have been blessed with gorgeous weather since last Wednesday, and it is forecast to last through this coming Wednesday. Yesterday afternoon, I put a 30 dB (specified to DC) attenuator on the antenna, and still no change. Hopefully we will have storms later in the week. It would be nice if that sequence continued forever, but it won't. So, I am spending my days cleaning up after winter. Many years ago, some naturalist in Ohio thought wild grape vines were beautiful along the roadside. They aren't. They are invasive and kill the trees (mostly ash and black walnut) and have "trunks" up to 5" in diameter. Black walnut is a particular target, and ash is already dead from the Emerald Ash borer beetle, so the surrounding forest looks a mess. Over the past two days, I spent about six hours -- about all I can take right now -- just cleaning up three walnut trees. I think two will make it; I am worried about the third.

Regards, John

 

Hello John,

I again found a PDF on a loop antenna.
The preamp is designed for 10 - 150 Khz.

Bertus

 

That is an interesting article and project. I particularly liked the theory as that is something I am weak at in electronics.

John

 

Hello John,

The PDF was found using the wayback machine on a broken link from this page on the EDUCYPEDIA about Loop antennas.

There will be more info for you over there.

Bertus

 

Got it! Thanks again. For others, here is an active link: https://web.archive.org/web/20050504190334/http://www.longwave.de/smlloop.pdf

When I save something, I always like to add the link as a sticky note.

John