Telamon wrote:
In article ,
weatherall wrote:

pure Wrote:
What a piece of CRAP this antenna turned out to be.......almost the
price of the radio itself !!!

This is why it's crap:

1) the reception is WORSE with the antenna, than using the whip
antenna on my degen radio, model DE1102 !!! I actually get the signal
properly, and can listen to the program with the radio, but then the
show disappears completely if Iuse the external DE31 antenna!

2) the batteries AAA inside the antenna, to power it, run down pretty
fast. I recharged a pair just before, and they were run down 2 or 3
hours later, when I gave up.

3) it's not clear how the de31 can give a better signal, unless you're
in a manhole, in a military bunker, underground and you need to have a
connection to the surface 5 m away. This would be the only conceivable
use for this antenna.

What a huge waste of money, this de31 !!!

I had problems with my DE31 until I figured out that the wire between
the antenna and the radio was backwards. I had the tuner close to the
loop at first, and it basically eliminated the signal. Maybe most
people don't make this mistake though.

I'm not familiar with this particular model but I would think that you
would want the tuner near the antenna.

I use duracell alkaline AAA batteries in my DE31 and they have been
there since last winter. They're still working.

Rotate the antenna so that the hole faces the direction of the
transmitter. If plugging the antenna in seems to provide poor
reception, try clipping it to the whip with the white clip, and clip
the black clip to a ground wire.

The "hole" in the antenna is the null or that which will provide the
weakest reception of a station. You want the edge of the electrically
small loop pointed at the station you want to receive. You point the
"hole" or null at a station or noise source you do not want to hear.

--
Telamon
Ventura, California

Yes, I would think that you would want the variable capacitor close to
the loop too. I think what we have here with the loop is just an
inductor. So in total we have a parallel resonant circuit. The KA-31
uses a very thin coaxial cable (near 10' long) from the loop to the
unit which resides nearer the radio and which contains the adjustment
to peak the frequency. I would say the inductance introduced by the
coaxial cable is low because of the geometry of the cable so that it is
probably insignificant when compared to the inductance of the actual
loop. Anyway, the KA-31& DE-31 antennas as I recall don't go down to
the 75m or 160m bands. I wonder if the antenna connected to a loop
with more turns or a larger loop might in fact go down to those bands.

Damned if I know what is in the unit by the radio. I suspect a
variable capacitor and a jfet like a mpf-102. I don't think a
varactor diode kind of setuup will tune such a broad range. I will
take my unit apart one day soon and report back to group if anyone
interested.

regards,
NEO