SID monitor

[Mike(Mont)]

I can't help seeing the similarities between the Gold Gun and some of these SID monitors. One is called the Gyrator III and there are other older versions like this link. Merry Christmas!

https://www.aavso.org/files/gyrator1.pdf

https://www.aavso.org/gyrator-iii-vlf-receiver

[abdou2014]

Thank you Mr . did you try to build this circuit or modified it for gold hunting

[Mike(Mont)]

No, haven't built one and don't know if it would work for gold. An outfit called FarCircuits.net sells the PCB.

[abdou2014]

do you have a good circuit of pistol detector or any thing who working nice

[Mike(Mont)]

You're going to have to find someone who knows more about it. i am probably the least knowledgeable in electronics of anyone on this forum. With the PCB this project looks easy enough that even I could build it. Maybe it needs to be modified to find gold, I don't know. But somebody here probably can answer that.

[Mike(Mont)]

Don't know what I did wrong but the PCB image doesn't show. It worked before. I give up. I'd delete it but can't figure out that either. You can view the PCB at FarCircuits.net receivers

[Geo]

With some mods gyrator can locate long time buried objects.

[abdou2014]

Hello Mr GEO . can you help us for build one please

[Mike(Mont)]

Originally Posted by Geo

With some mods gyrator can locate long time buried objects.

Power supply and antenna for starters?

[Seden]

Mike,

I know the Engineer that gave the author of the Gyrator receiver the idea of using a Gyrator. Phil Eide and I have been friends since 1982 and once in awhile get on 40 meters SSB. He used to work at Bunker-Ramo then Hughes Aircraft Missile Systems group in Canoga Park,CA. He's a real sharp practical Engineer. You can make some high Q filters with the Gyrator topology.

Randy

[Mike(Mont)]

Hi Randy. Yeah, those SID monitors are sensitive and I wonder why people around here are not interested. Guess they have too much invested in their own designs and don't like the idea of something so easy and inexpensive. I bought a Gyrator PCB but haven't built it yet.

[abdou2014]

Hi. i'm interested to this project .

[Mike(Mont)]

Well, I suspect you would need a rotary switch with different capacitor banks for each frequency you want. And like Geo says you probably will want a beep generator circuit to alert you when on a signal. Will it work? Geo says he doesn't think so. i don't know but it looks plausible, but I am not that skilled in electronics and never built a pistol detector.

[abdou2014]

Thanks. i have signal generator with loop antenna like transmiter and rotary switch . first i'll build pcb .

[abdou2014]

almost finished . which frequency you advise me ?

[Golden]

Try 21,75 khz.

[taxma1981]

[Mike(Mont)]

Originally Posted by abdou2014

almost finished . which frequency you advise me ?

I have a question for you. How is the "Constant of Time" connected? You see there is an arrow there. Looks like it connects between C7 and C8 but I don't know. All the other components have a symbol where they go, but there is no symbol there. And the holes are drilled larger like there are wires that connect there. This is on the Gyrator III PCB. Maybe this is just a jumper switch to engage C8 so the data recorder only takes samples every few seconds? Without C8 connected it is continuous? I think C8 is not needed if this is the case.

[Mike(Mont)]

Poly capacitor 1000pf
Digikey part number
399-7693-ND
Mouser part number
505-FKP21000/100/2.5

[Mike(Mont)]

I don't know if you've built the loop antenna yet, but I know it's better to keep the windings all on one layer. The instructions do not allow this as the notch on the frame is not wide enough. So I put some feet on the cross braces about 10cm wide. Best to use half-round pieces, but I used 1" x 2" pieces and rounded the corners a bit.

To wind the loop, I first put the magnet wire onto an old bicycle wheel rim. This way you can wind it tightly. It's doesn't work very well if you try to wind it off the spool. You can't pull the wire tight. Also clamp the cross braces down to a table so you can pull the wire tight but not so it stretches too much. A small amount of stretch is needed but be careful or you will break the wire.

[abdou2014]

can you post a picture of antenna

[Mike(Mont)]

Send me your email in a private message.
I can't get this to work.

[Mike(Mont)]

I don't know what the deal is around here. No one wants to send their email address. Gives me the creeps.

Do a search for Stanford Solar Center

Click on "Space Weather Monitors"
Click on "SID Monitor"
Scroll down the page to "Antennas"
There are instructions and photos there you can download.

[abdou2014]

thank you !

[Qiaozhi]

Originally Posted by Mike(Mont)

I don't know what the deal is around here. No one wants to send their email address. Gives me the creeps.

All you need to do is go to a post by abdou2014 and click on the name. A drop-down box will appear. Then click on "Send email to abdou2014".