Graham wrote:
Simple tuner
If it works on top band, then it will work on 500 (with a bit more C)
.. this is a simple parallel tuner , with a WW2 ex usa surplus
transmitter coil, and a 2000 pf capacitor 4 x 250pf wired in
parallel , Worked well on rx and would handle up to 25 watts on tx
before the plates flashed over ! but easy to make easy to tune ,
rx/tx tapped 2 turns from the bottom and the Ae direct to the top
(the knob is from the B set .. ws19)
http://uk500khz.googlegroups.com/web/Parallel+ATU?gda=AekYBT4AAAD_AR9CZEwmTaUFcglf9MHbexqv2sBQZsAxVg3n14BVSpRSVTbPEv7Iv69fZDO_RFvjsKXVs-X7bdXZc5buSfmx
G ..
*From:* Chris <mailto:[email protected]>
*Sent:* Monday, October 06, 2008 11:12 AM
*To:* RSGB lf Group <mailto:[email protected]>
*Subject:* LF: ATU
Hello Tim,
My ATU is really a large matching coil. It consists of 130 turns of
insulated solid copper wire on an 11.5cm dia. cardboard former (carpet
roll centre) tapped every ten turns (course tuning) in series with a
coil of 22 turns of 18 swg enam. copper wire, 7cm long, 6cm dia. and
tapped every two turns (fine tuning). I find this will resonate my
124' wire from Medium Wave, through 500kHz, to all the NDBs.
I built this so I could use it for TX one day. If you are going for RX
only, take a look at 'LF Today', second edition, p14 and 15. This is
my next project, got all the parts, building this week.
All the best.
Vy 73,
Chris, G4AYT, Whitstable, Kent.
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10/5/2008 09:20
Thanks Graham, I've actually got a full set of these coils which came
from Hanslope Park, I wonder what they were used on.
Anyway I've found a suitable cap from a high power MF Tx on another site
so when that arrives I'll be well away. I understand its possible to get
some power
out of my 756PRO3 so then I'll have a look at that next..
Tim M0AFJ
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