QRP

[ivconic]

Perhaps the Deus is programmed to malfunction in the low-frequency end of 2016.
So you'd like/must to buy the new V4 search coil???


-- .- -. . -.--
-- .- -. . -.--
-- .- -. . -.--
-- .- -. . -.--

"Maney"???

-- --- -. . -.--

[Nupi]

"Maney"???

-- --- -. . -.--

... .... .. - you can really Morse.

[Nupi]

May be the cause of the behavior of the Deus is: Quantum magnetism interference.

[rickb]

And just 6-7 months ago situation was quite opposite; it was instable on 18kHz and very stable on 12kHz !??

Component drift due to temperature change? spring vs fall temps?

Rick

[ivconic]

Component drift due to temperature change? spring vs fall temps?

Rick

Yes usually that's the common cause for such behavior.
Deus is not having much of a components though, one chip and just few SMD components, closely packed and sealed.
This is rather connected with geomagnetic changes and disturbances, propagations, sun activity etc.
Also could be interference with some artificial (yet unknown for us in a gang) RF source, noise, harmonics etc.
It seems it is "seasoning" event.
Even if it is coming from artificial source; such "seasoning" change of working regime maybe is present at that source and not at Deus.
Maybe that source is lacking of stability or is viable to another outer disturbation events.
Who will know? These days is very hard to distinguish between all possible causes because there are so many artificial frequencies and waves in air.
High resolution DSP field meter and spectrum analyzer would probably help.

[Dave J.]

I am planning to experiment bit more with VLF/ULF (bellow 200kHz) ideas later this winter.

Now THAT brings back some fond memories from the 1980's when I was very active in the Longwave Club of America. http://www.lwca.org/ Ran an FCC Part 15 beacon about 187.5 kHz, radiated power calculated about 13 microwatts and empirically it seemed to be about that. It was regularly received at distances of over 100 km and occasionally (at a very good location and good conditions) at about 300 km. I can still hear it in my mind, dah didit, didah dah dah.

There was nothing particularly special about the transmitter other than that it was simple and worked well. It was the receiver that I was proud of. Direct conversion phasing type SSB receiver a little bigger than a pack of cigarettes. At home I used the transmitting antenna on the roof as a receiving antenna, but for fieldwork I built a "fake active whip" -- whip antenna series resonated with a tapped RF transformer to get a decent noise figure out of the receiver. Only controls were antenna tuning (fairly broad), receiver tuning, audio volume (gain in the audio amp chain), and a switch for wide or narrow audio bandwidth.

At a nationwide club meeting of about 100 members and friends in Scott's Valley (south of San Francisco), one of the fellows I knew pretty well had his table full of equipment set up (he was a ham radio operator with real communications receiver and various accessories for enhancing reception, you know the kind), and someone had rigged up an antenna outside. Just for fun we raced his table full of electronic wizardry against my little receiver that fit in the palm of my hand. We came to the conclusion that for the purpose at hand (detecting 1750 meter band beacons) it was nearly a tie, his was maybe a couple decibels better.

For field transmitter work, I had a 1 meter loop antenna with its own beacon, just walk down the street with it running. The other thing I had was a variable inductor that I could use between a ground rod or ground connection and the car body, and series resonate it so the car itself was the transmitting antenna. The same arrangement could be used for receiving. How well it worked depended a lot on the condition of the ground, with low conductivity ground increasing the effective dipole length but introducing a lot of ESR.

[ivconic]

"... It was the receiver that I was proud of..."

Exactly! That's the part which interests me more.
Nice memories Dave, nice story, very pleased to hear it!
That brings me back to my story, some 26-28 years ago when all that made so much sense. No cell phones, no Internet, no IPTV, only 2 tv channels.
Radio communication was something like "window to another world". It was "the Internet" on its own!
Since 80m and 40m were strictly regulated by the law and were reserved only for colleagues with a higher experiences and grades; i started as plain amateur at citizens band (many of us started that way).
But pretty soon i risen interest for other bands. In the start of '90s i met the 2m for the first time. Wow! It was a thrill to hear crystal clear voice from another side (unlike noisy CB).
And i founded myself in 2m for longer period. Main reason was because i had one of the most popular repeater pretty near my home, so i was the king!
Almost with no effort, with very low power (sometimes only 1/2W) and with poor antenna; i had very clear reception so as transmission.
But i preferred the reception only for longer period. I was shy for talking around with much more experienced people. Second reason; i hated my own voice to hear and how it sounds!
In the end of '90 lot of obsolete military equipment was very easy available and cheap to come by. So i made huge collection of various "sweets" at home. At some moment my spouse was about to cut my throat at sleeping because of the "mess" i brought to home!
I managed to obtain the famous AN/GRC-9 in a shape that you wont believe it! It was new and shiny as it was produced a moment ago!
No wonder; Yugoslavian army was directly connected to USA army (until 1991. we were close allies) and got all the possible help in such technology after the WWII.
So those units were conserved and kept for the decades in military reserves, almost forgotten, until one day they decided to clear up and free some space.
At one moment i had almost all devices from this list: http://www.radista.info/hf_radio.htm
Also i had dense "net" of various antennas around my home, in my backyard and on my roof! It was literally a "war zone" ... a "death zone" ... in eyes of my spouse and the rest of family!
So at some point i had decision to make; either i shall remove most of those... either i shall be removed myself completely!
But best moment in whole story was when i obtained two small transceivers RU2/2 (RUP2a and RUP2b), covering from 27-38Mhz and 38-54Mhz, from this list: http://www.radista.info/vhf_radio.htm
With those i "bought" some time and lot of "sympathy" at my spouse; because with those you could literally receive and spy all the cordless telephones in a 15km range at the time!!!
Since i am located on the hill (a hillbilly !!!) and i have whole city just infront of my eyes down the hill; i could easily catch and listen literally all existing cordless telephones in a whole radius!
Wow! You can't imagine a joy at my spouse to listen all the rumors and gossips for free and undercover! Spying people is a hell of a joy!
In meantime i made several diys, learning and progressing step by step. I ended up being able to diy pretty complex 80 channels 2m digital transceiver, which was the top of my works on that matters.
Later i made 20-30 of those for sale. I am still keeping some of the documentations.
But as we get the ADSL Internet here, some 12 years ago, radio started to lose significance and year by year it slowly died. I sold or gave away most of my equipment. It was too hard to find proper room and place and keep those nice things.
Lot of people gave up from radio, nobody to communicate with (QRP, short ranges, since i don't have license for better)... or just few people randomly and rarely in the air. And that's the main reason why i lost enthusiasm. Internet finally won.

[ivconic]

Speaking of ULF/VLF, i risen huge interest on those after i gained some live experiences playing with Fisher Gemini II, White's TM808 and finally (the most significant for me) Cscope 33XD, the utility detector, operating at 33kHz.
Also i had shorter experience with Emfad UG12/24, operating at 130~156kHz.
This is still pretty "misty" area for me. More are the things i don't understand there than the things i do understand.
And few years ago i got two interesting books as gift from a friend:
1) Der Selbstbau von LFVLFOrtungsgeraten; Wolfgang Friese & Wilhelm Herbst Verlag
2) Ortnungstechnik im LF; Wolfgang Friese
Both are dealing with similar designs.
Somehow... once i got good literature and lot of good sources to start working something useful; i am lacking of time, i can't spare some time in continuity to be completely focused on that topic.
Maybe this winter...

[Dave J.]

For a while I was interested in underground communication (funny, Minelab is now in that business....), specifically portable hand-held VLF/LF for cave exploration but also hardrock mining. Had some great stuff on paper that I never had the time and resources to actually build. One thing I actually did build was a Fisher TW-6 that I converted to voice single sideband. Voice quality was poor and distance was only about 100 meters, but it was fun to do it. I converted another TW-6 to 60 kHz to receive the Fort Collins standard time signal WWVB. Nowadays you can buy wristwatches that use that signal to keep time by atomic standard.

One portable loop antenna I was proud of: a big hank of coaxial cable, about 20 turns 1 meter diameter. For carrying it was floppy, you could stuff it in a knapsack or whatever. It was designed to be self series resonant, the shield was ground and the center conductor was driven through an impedance matching transformer. Polyethylene dielectric and woven shield, the thing had fairly high Q. Off-resonance was OK because the transmitter was designed for automatic impedance matching and could drive reactive loads efficiently.

As a kid growing up, I knew people who were ham radio operators but the ham radio bug never really bit me. I did like shortwave DX and since Radio Free Europe bored me to death, I listened to Radio Moscow and Radio Havana and learned a bit of Portuguese from Radio Brasil-- three radio services I was able to receive on a somewhat regular basis. One time I DX'd XERB (AM radio, Tijuana Mexico) on my very good crystal set in Sacramento California, a distance of (wild guess) a thousand kilometers.
For a kid interested in electronics, it was a great time because of all the WW2 war surplus stuff being dumped onto the civilian market (we really lucked out with all the military installations around Sacramento including the Signal Depot), and because people were buying new televisions every several years and throwing the old ones out. I didn't watch TV, I tore apart TV's to get the parts.

And being a kid then was different from nowadays. Back then, parents were too busy taking care of adult stuff to have the time and energy to micromanage their kids. There was no such thing as "soccer moms". We had pretty wide latitude to do anything we wanted as long as it didn't burn the house down or land anyone in jail. Our parents didn't know half the stuff we did, and it's just as well they didn't know. We learned stuff the hard way and we learned it well.

[ivconic]

For a while I was interested in underground communication (funny, Minelab is now in that business....), specifically portable hand-held VLF/LF for cave exploration but also hardrock mining. Had some great stuff on paper that I never had the time and resources to actually build. One thing I actually did build was a Fisher TW-6 that I converted to voice single sideband. Voice quality was poor and distance was only about 100 meters, but it was fun to do it. I converted another TW-6 to 60 kHz to receive the Fort Collins standard time signal WWVB. Nowadays you can buy wristwatches that use that signal to keep time by atomic standard.

One portable loop antenna I was proud of: a big hank of coaxial cable, about 20 turns 1 meter diameter. For carrying it was floppy, you could stuff it in a knapsack or whatever. It was designed to be self series resonant, the shield was ground and the center conductor was driven through an impedance matching transformer. Polyethylene dielectric and woven shield, the thing had fairly high Q. Off-resonance was OK because the transmitter was designed for automatic impedance matching and could drive reactive loads efficiently.

As a kid growing up, I knew people who were ham radio operators but the ham radio bug never really bit me. I did like shortwave DX and since Radio Free Europe bored me to death, I listened to Radio Moscow and Radio Havana and learned a bit of Portuguese from Radio Brasil-- three radio services I was able to receive on a somewhat regular basis. One time I DX'd XERB (AM radio, Tijuana Mexico) on my very good crystal set in Sacramento California, a distance of (wild guess) a thousand kilometers.
For a kid interested in electronics, it was a great time because of all the WW2 war surplus stuff being dumped onto the civilian market (we really lucked out with all the military installations around Sacramento including the Signal Depot), and because people were buying new televisions every several years and throwing the old ones out. I didn't watch TV, I tore apart TV's to get the parts.

And being a kid then was different from nowadays. Back then, parents were too busy taking care of adult stuff to have the time and energy to micromanage their kids. There was no such thing as "soccer moms". We had pretty wide latitude to do anything we wanted as long as it didn't burn the house down or land anyone in jail. Our parents didn't know half the stuff we did, and it's just as well they didn't know. We learned stuff the hard way and we learned it well.

"...underground communication..."

Such technology is still very expensive. Last year i made "cave logger" as a part of larger IOT project. One of the questions was on how to collect logged data from "node" units which are scattered across the cave. For temporary we ended up with solution that "officer at duty" must walk from node to node and manually replace medias with logged data. Which is uncomfortable, time demanding, tedious and dangerous. Next step i did is to introduce BT connectivity at nodes. The same "officer" now is not forced to manually replace medias but he can "download" logged data from certain distance (10-15 meters). Yet still he must enter the cave and walk certain path. Again not the right solution!
Ideal would be uniform connection at cave's entrance, sort of "server" connected wirelessly to all nodes. Very tough task! Expensive too! Still "cooking"... Main problem is significant signal losses across the cave. Another semi-solution which i am examining is Lecher principle approach, simplified; one bare wire across the whole path. But that opens quite new questions and problems.


"...a big hank of coaxial cable, about 20 turns 1 meter diameter..."

That's pretty efficient and is frequently used as "link" from one stage to another in professional broadcasting systems. Though with much smaller dimensions, but concept is the same. I've seen those in umeter ranges. Very efficient!
And the very similar design i saw on some amateurs page, exactly covering below 150kHz range. It was offered there along with interesting receiver project, i lost that link but i will find it.

"...it was a great time because of all the WW2 war surplus stuff being dumped onto the civilian market..."

Yes, same thing happened here, but much later, in the middle of '90s. You were in a huge advance, having such conditions much earlier.

"...And being a kid then was different from nowadays..."

Oh please don't remind me! Here too, the "golden era" comparing to now days.
Today kids are literally handicapped with wrong excessive attention and too much instant technology. They will learn nothing except to become brainwashed robots.

"...We learned stuff the hard way and we learned it well..."

I'd never learned anything about the TV if i was not shaken&shocked so many times by high voltage from LOPT !!! Nor i'd ever have such a nice curls in my hair!
(nor i'd have any of present weird ideas which i do have ...)