[Antennas] Re: Antenna question ( receiving )

Sun Oct 3 18:35:52 EDT 2004

----- Original Message ----- 
From: "capn2" <capn2 at comcast.net>
> I'm hoping to get at least a receiving
> antenna up before the snow flies and am considering this one:
> http://www.universal-radio.com/catalog/sw_ant/3368.html

I'm in the same boat and the active antenna i'm considering, for receive,
is the Wellbrook loop. Do a google search and you can find the 
manufacturer as well as reviews, which are highly positive. If you're 
troubled by noise, as i am, i just don't think these short vertical wire
active antennas will do much good. Despite the snake-oil claims of the
seller of the antenna in the link you posted. Magnetic transfer technology
means balun ( or unun ) transformer on a torroidal core, so i don't know why
the seller cannot just tell you that instead of trying to mystify you. The
Wellbrook is untuned but the circuitry, i believe, is way more sophisticated
than the naysayers out there know; i believe the circuit, or very similar, showed
up in Elektor magazine ( Netherlands ) about 10 years ago, if you want to build 
one. It has some clever circuitry to maintain in a constant range the impedance
of the loop which would otherwise vary greatly over the tuning range of the
antenna compared to the input of the transistor amplifier.
Since the Wellbrook, and the antenna you were considering, are only
receive antennas, since they have a preamp, another solution might be the MFJ
loop antennas, i think called MFJ-1786 and there's another one that tunes lower,
down to 7 MHz. These would give you lower noise than a wire or short vertical
inside the house, as well as transmit. The possible downside is that the MFJ 
requires retuning for different frequencies - unlike the Wellbrook or the one you
were looking at, which are no-tune. Also- i think the automatic tuner on the MFJ
requires you driving the antenna with about 1 watt of RF. I think the one with
the simpler tuner with only UP-DOWN tuning buttons to control the motor "might"
not require an RF source to tune it but as i don't actually have the antenna, i do 
not really know. But i definitely think the small-loop antenna is the way to go.
So, that all sets your decision back to undecided, doesn't it, hi?
-Hue Miller