TimeForceBlue wrote:

Anyone have a Select-A-Tenna? Then tell me what you think of it! :-)

MW loops work fine. There's little point to getting more than
the passive one.

They match the impedance from free space to the radio loopstick
and greatly increase the sensitivity of most radios.

They're all, depending on how you look at things, overpriced as to
the parts that go into them (a hundred feet of wire and a variable
capacitor), but you won't make one as neat yourself, and they do
really work.

Odd facts :

1. They mostly work only in the daytime. They're able to bring the
received signals (noise and signal) up higher than the internal noise
of the receiver, and so let you hear out several hundred miles even
at noon with an insensitive radio.

At night, the problem is too many signals already, and so bringing them
up pays no dividends, just makes everything you already hear louder.

So when you get one, try it in the daytime first to see the effect.

(Terk loop is an alternative ; Radio Shack used to have one as well.)

2. An already sensitive radio sees less improvement. Once the
propagating noise level is above the internal noise of the receiver,
there's no further advantage to bringing it up more. Insensitive
radios see spectacular improvement.

3. Claims of great directionality are made, and putting the radio
and loop on a lazy susan is a nice idea that works. The radio itself
however has the same directionality. All small antennas have the
same antenna pattern.*

--
* Finely made MW loops like the big Kiwa MW loop, actually get deeper
nulls, by designing to eliminate every response to electric fields.

The antenna responds to both electrical and magnetic fields, and at
the null of the magnetic field antenna, you're left with a non-cancellable
electric field, which fills in the null. The insensitivity of the loop
to electric fields is what determines whether you get really spectacular
nulls or not from a well-made loop.

If you're just coupling in the usual way to a standard MW loop with
your radio, you take what you get. One loop isn't better than another.

--
Ron Hardin


On the internet, nobody knows you're a jerk.