[ARC5] Unun measurements

[Jack Antonio]

I apologize if this is a resend, it appears it didn't go
through the first time.

Ok, so I did some measurements. Not really trying
to prove or disprove any particular point of view,
but just thought I'd document what I see with
my particular test bench.

Using a BC-696, with a BC-456/DM-33 as a power supply.

Frequency 3885 kc, all CW mode. In all cases, antenna
loading coil tuned for maximum power out.

First: An 8 ohm non-inductive resistor in series with 90
pf transmitting mica. (Assuming the radio shack resistor
really is non-inductive like it says).

46V P-P across the resistor which works out to 33 Watts
BC-442 meter says 1.0, antenna coupling control at 4.
With a small sampling loop placed around the antenna
lead, second harmonic measured -50db.

Next: 100 pf cap in series with 50 ohm load. Measuring
with Bird 43.
Power out is 43 watts, antenna coupling
control at 10. BC-442 says .25.  Second harmonic -42db.

Next:  4:1 unun to 50 ohm load, no series capacitor.
15 Watts out, antenna coupling at 10. Loading coil at 0.
BC-442 meter wiggles a little.  Second harmonic only -28db.
I would have thought the antenna coupling control would have
been around 4 or 5, but this didn't happen.

Last:  4:1 unun, with 100 pf capacitor in series to 50 ohm load.
38 Watts out, antenna coupling at 5. BC-442 says 1.25. Second
harmonic -52 db.

Sure like the way the dynamotor lugs down as the transmitter
is brought into tune.

Jack Antonio WA7DIA/4