"Paul Burridge" wrote in message
...

Hi gang,

I've never had a lot of luck with GDMs for some reason. Even with a
decent meter, it seems such a drag tuning across such a vast range
looking for a tiny, easily-missed dip which you have to screw out of
the meter by forcing the sensing coil so far into the circuit
concerned you practically break the circuit board. Am I alone in
finding this potentially invaluable device practically useless in
practice? Is there a more viable alternative?

p.
--

It is kind of hard to get the proper coupling on PCB style coils.
You may have to use a link coupling system (came with some
of the Millens); also solid state circuits can have fairly low Q
circuits, again making it hard to see the dip.

Those were intended for larger tube circuit designs, not PCB
based gear.

Pete

On Sat, 15 Nov 2003 17:06:34 -0500, " Uncle Peter"
wrote:


It is kind of hard to get the proper coupling on PCB style coils.
You may have to use a link coupling system (came with some
of the Millens); also solid state circuits can have fairly low Q
circuits, again making it hard to see the dip.

Those were intended for larger tube circuit designs, not PCB
based gear.

Item 2.4 described on http://home.online.no/~la8ak/5c.htm
is the solution for dipping pcb coils, and you don't need a
griddipmeter, at all. Another problem with the pcb coil is low
Q-value, and if the coil is loaded too much it won't dip with any
arrangement tried.
also described some GDMs on http://home.online.no/~la8ak/5a.htm -
haven't got the time to re-edit these pages

Jan-Martin
LA8AK
--
remove ,xnd to reply (Spam precaution!)

On Sat, 15 Nov 2003 17:06:34 -0500, " Uncle Peter"
wrote:


It is kind of hard to get the proper coupling on PCB style coils.
You may have to use a link coupling system (came with some
of the Millens); also solid state circuits can have fairly low Q
circuits, again making it hard to see the dip.

Those were intended for larger tube circuit designs, not PCB
based gear.

Item 2.4 described on http://home.online.no/~la8ak/5c.htm
is the solution for dipping pcb coils, and you don't need a
griddipmeter, at all. Another problem with the pcb coil is low
Q-value, and if the coil is loaded too much it won't dip with any
arrangement tried.
also described some GDMs on http://home.online.no/~la8ak/5a.htm -
haven't got the time to re-edit these pages

Jan-Martin
LA8AK
--
remove ,xnd to reply (Spam precaution!)

Uncle Peter wrote:

It is kind of hard to get the proper coupling on PCB style coils.

Bingo.

Those were intended for larger tube circuit designs, not PCB
based gear.

Daily Double!

Dana

Uncle Peter wrote:

It is kind of hard to get the proper coupling on PCB style coils.

Bingo.

Those were intended for larger tube circuit designs, not PCB
based gear.

Daily Double!

Dana