Dear James, LF group,
In the end, I just used the wire from the Decca coil and scrapped
the rest. As a former, I found a "sectional manhole" made by Osma
was very suitable. This is a brown PVC cylinder about 500mm
diameter and 350mm long, with external ribs. It is meant to form the
walls of manholes for drains, and several sections can be slotted
together for a bigger former if needed.
I found one of these Osma 'sectional manhole' units at the local builders
yard - they seem ideal LF coil formers and I wondered how I had missed them
before. I had hunted around all sorts of DIY and builders yards in the past.
About 6 turns of the Decca litz wire fit between each pair of ribs,
forming a winding 3 layers deep by 2 long. about 80 or so turns
altogether gave me the required inductance, which has a Q of
about 700.
What was the inductance of your 80 turn coil?
. I am using a
second sectional manhole wound with more turns of smaller,
ordinary stranded wire for 73k, which stacks on top of the 136k
loading coil.
can you give details of the second coil?
Regards,
Peter, G3LDO
e-mail <[email protected]>
Web <http://web.ukonline.co.uk/g3ldo>
| 