parnass@ihuxf.UUCP (Bob Parnass, AJ9S) (06/11/84)
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MFJ 1020 Active (Indoor) Antenna
The MFJ 1020 Active Antenna consists of a telescoping
antenna and a preselector-type circuit inside the now fami-
liar beige and wood grain cabinet. The frequency coverage
of approximately 200 KHz to 30 MHz is divided into 5 bands.
A small, external power supply is required, but not provi-
ded.
The 1020 lists for $80 new, but I purchased it at a hamfest
for $20, and performed one minor repair (replaced a fiber
washer at the base of the telescoping antenna). I use this
unit with an ICOM R-70 general coverage receiver. Overall,
the MFJ 1020 works better than expected, although still not
as good as an outdoor antenna.
The Bad News
Phono jacks are used rather than the SO-239 type.
The inclusion of an LED indicator lamp in the 1020 really
precludes the prolonged use of any internal battery.
One problem with my particular unit is that, despite the
dial markings, coverage ends at about 28.5 MHz (rather than
30.0 MHz). There is no simple trimmer capacitor that can be
adjusted as a remedy. One of these days (yawn), I'll have
to trim an inductor.
Active antennas are more prone to electrical interference.
A photoelectric night light in an adjacent room causes a
high QRN level, due to the SCR in the dimming circuit, and
must be disabled during listening periods. Emissions from
the horizontal oscillators of TV sets in the building also
cause problems.
Use of a narrow band (tuneable, in this case) antenna makes
"instant QSY" impossible. One cannot make full use of the
broadband capabilities of the new generation of general
coverage receivers. This is a shame, especially if one has
a receiver such as the ICOM R-71 or the Kenwood R2000 which
contain several memories.
The Good News
The MFJ 1020 works! The bypass switch on the front panel
allows quick in/out comparisons.
The 1020 has a jack on the rear for another antenna. (This
jack is always connected to the telescoping antenna.) I use
a 30 foot piece of wire connected to this jack, and dressed
internally around a window frame. In this setup, the 1020
is used essentially as a super preselector, and it permits
me to hear many more stations than using the telescoping
antenna provided.
Using the 1020 and some wire indoors allows one a fair level
of SWL'ing.
Closing Comments
If you are in a condo/apartment situation, I recommend
buying an MFJ 1020 at a hamfest or a sale. Like many MFJ
products, it looks good on the outside, but you may feel
guilty if you've paid the $80 list price after looking at
the simplicity inside.
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Bob Parnass, AT&T Bell Laboratories - ihnp4!ihuxf!parnass - (312)979-5414