Greetings,
Now we have the final details of the upcoming CLE 116, Barn Door event,
attached is a new picture of my 1 AD, ie One Active Device receiver,
and which I will use during the CLE.
It uses just one active component, a dual gate Mosfet type BF960, the
power supply is an ordinary PP3 9v battery. The transformer a normal
mains supply ( European) 0 - 220 volt primary and 0 - 20 volt secondary type.
A Hi-Z pair of headphones is essential, however Steve Ratzlaff has reported
using 600 ohm headphones made by JRC, type ST-3 and available from
Universal Radio in Ohio. I have already ordered a pair. The Hi-Z phones
I use at present are World War 2 vintage and tend to be a little sore, physically,
on the outside of one's ears, over a protracted listening period. They are DLR5's.
No effort has been made to tidy up this set, rather it is a test bed for experiments.
Note that a simple single turn link can be used on the ferrite rod to feed a
frequency counter and although the "offset" is not strictly accurate, it nevertheless
gives one a very good idea where one is on the NDB band.
Some figures now, for those having a go building Mike Tuggles receiver and on whose
circuit my receiver is based. Thanks to Mike for sharing this circuit with us.
Using a main tuning capacitor of 0 - 450 pf.
1. Main tuning coil measured 627 uH on the ferrite rod.
2. Feedback coil measured 266 uH on ferrite rod, should be smaller in value, but worked for me.
3. Antenna coupling coil 4 turns of 20 SWG enamelled copper wire.
4. Frequency counter link 1 turn
( Note: The feedback coil of 266 uH, used about 60 turns of Litz wire. This will give you
an idea of the number of turns needed. Work up the value for the Main tuning coil )
No need to use enamelled copper wire, it just formed easy, use what you have. I used Litz wire
for the Main and Feedback windings. Use what you have, scramble wind to fit, just to get going.
Later you can use Litz for best efficiency, but with a week to go to the Barn Door CLE 116 it
is best now to just build, and improve later on, when you have the time.
If a One Active Device is not realisable without Hi-Z phones, use the secondary winding of that
mains transformer to feed a signal to a basic LM386 audio amplifier, so you can run your
ordinary 8 ohm speaker. Or, instead of that speaker, plug in your 8 ohm headset , adjusting
the volume to suit.
Best of luck in this interesting, upcoming CLE 116.
Finbar O'Connor Malin , County Donegal, Ireland.
REU 
Sivu: 1
CLE 116 (Luettu 4861 kertaa)
