Hammerhead Rev D discussions

[Rob in KS]

HH enclosure question

I have a nice box aluminium box that would be perfect for the HH.
I was thinking about the shielding the box would provide. I'm planning on using a panel mount BNC for the coil, that puts the box at GND or VB+. The audio jack barrel is at VB- and contacts the box. What do you all think?

Isolate one of them ?
Capacitor couple the audio to the jack?
Use a plastic box ?

[Carl-NC]

Hi Carl n forum friends
Excuse me for butting in Carl ..
but I am using an LT1054 http://oh3tr.ele.tut.fi/~ftp/pa/cly10amp1/lt1054.pdf

It may be a little more expensive thou.
cheers
gef

This looks good, 15v too.

[Carl-NC]

I have a nice box aluminium box that would be perfect for the HH.
I was thinking about the shielding the box would provide. I'm planning on using a panel mount BNC for the coil, that puts the box at GND or VB+. The audio jack barrel is at VB- and contacts the box. What do you all think?

Isolate one of them ?
Capacitor couple the audio to the jack?
Use a plastic box ?

Yes, you will need to isolate them. I would use the coil ground for the box, then use an insulated jack for the audio. There are plastic bushings available for this. Don't think cap coupling will work.

- Carl

[Charles (Upstate NY)]

A friend of mine just got his new HH boards. He says these smaller boards fit nicely in an inexpensive waterproof polycarbonate case he is using. If anyone wants to make a waterproof version I'll try to get a part number and post it.

Charles

[Rob in KS]

Large Coil

I'm wanting to build a 1m coil. I know I need to lower the frequency, increase the coil pulse width and delays. Any suggestions for values:

C8 Freq
C24 Main Delay
C25,C26 Secondary delay

What should the coil pulse width be? The main and secondary delays?
Any other changes?

My first one was built according to the schematic and works great with a 10" homebrew coil.

[Carl-NC]

I'm wanting to build a 1m coil. I know I need to lower the frequency, increase the coil pulse width and delays. Any suggestions for values:

C8 Freq
C24 Main Delay
C25,C26 Secondary delay

What should the coil pulse width be? The main and secondary delays?
Any other changes?

My first one was built according to the schematic and works great with a 10" homebrew coil.

I posted the component changes several months ago, and I cannot find my notes to repost them. See if you can find them, I'll keep looking for my notes.

- Carl

[Rob in KS]

1m Coil

I looked through the HH forum, but didn't find it. I found some info from Eric.
Tx Pulse 500uS
Main Delay 60 - 100uS
Sec Delay 1000uS
Heatsink Q3, Larger R11
I can figure these out, so don't go to a lot of trouble.

He said that the integrating caps need to be 4 to 5 times larger. I'm going to build up my second board and make the changes. When the weather cooperates, I'll drag the whole thing outside. I can't run my 10" coil inside.

Thanks

[Functional]

I looked through the HH forum, but didn't find it. I found some info from Eric.
Tx Pulse 500uS
Main Delay 60 - 100uS
Sec Delay 1000uS
Heatsink Q3, Larger R11
I can figure these out, so don't go to a lot of trouble.

He said that the integrating caps need to be 4 to 5 times larger. I'm going to build up my second board and make the changes. When the weather cooperates, I'll drag the whole thing outside. I can't run my 10" coil inside.

Thanks

This link might help:
https://www.geotech1.com/thuntings/a...hp/t-7718.html
Or this Google search of the forum:
http://www.google.ca/search?num=100&...G=Search&meta=

F.

[Functional]

IC7 is the 4066 chip; a b c d are the 4 gates inside that chip; d is not used in the design. This is a common issue with schematics, where a physical chip can have multiple circuit items. IC8 is another example, where one package contains 2 opamps. My schematic software doesn't let me delete gates that aren't used.

- Carl

Hi Carl

I was reviewing posts and was wondering what schematic software you use? Do you use the same software for the component layout for the PCB, or different software? Would it be possible to see what the other files look like that are generated when you do the PCB? I'm interested in seeing how they store the information for the components. I'm also interested in finding out if your software has a BOM (Bill Of Materials) option?

On another note. I know you get a lot of email and likely don't have a chance to get to it each day, but I sent a reply today about the posting problem I had, (and another matter).

F.

[Carl-NC]

I use Easy-PC, from the UK, for both schematics & PCB. Yes, it will do a BOM. Everything is stored in binary.

- Carl

[Buzz(ID)]

MY HH

I hope all of the componets are correct?


Buzz

[1843]

positive voltage doubler

Carl,
I have seen in many circuits which pin5 of 7660 is shorted to gnd.
Why do you have left it open?...
Regards.

[Carl-NC]

Carl,
I have seen in many circuits which pin5 of 7660 is shorted to gnd.
Why do you have left it open?...
Regards.

Pin 5 is normally used as an inverted voltage output. I'm using the 7660 as a voltage doubler, not a voltage inverter, so I don't need pin 5. You can ground it or leave it open, it doesn't matter. If you ground it, the chip wastes a little more power pumping unused charge to ground.

- Carl

[1843]

OK!

Thanks Carl,
You are right.
Cheers

[Unregistered]

What does Q10 do in the rev D of Hammerhead?

Thanks