I have been using the Sony ICF SW-77 receiver either with the whip antenna
or a variety of indoor antennae for the last several years. In all of these
configurations, I did not have an earth ground available to use with the
antennae (I was an apartment dweller).

Now my circumstances have changed and my wife and I find ourselves moving
into a suburban house with a sizable back yard, apparently ready made for
setting up a permanent longwire antenna with a good earth ground. My guess
is that the antenna that I can put up will be 100 to 135 ft long. I plan to
bring the signal in to my radio on 50 ohm coax, and I am planning to use a
grounding block (gas discharge?) similar to those used for CATV
installations.

My question is, will I notice a significant improvement with this system? I
am mindful of the possibilities for signal overload, but I plan to run the
gain control in its "MEDIUM" or "LOW" settings unless I am interested in
listening to difficult stations. I am particularly interested in hearing
tropical band stations in Africa, Central/South America, and the Pacific.

My general impression of modern receivers is that they're already really
sensitive. You get more signal and equally more noise from a bigger
antenna, so you're not ahead once you're above the internal noise of
the receiver, which is what is low in modern receivers and so you
don't see much advantage once you're beyond the minimum antenna.

On the other hand, you get increased intermodulation and overload
from other signals you're not meaning to listen to, and that's
something modern receivers are not designed to suppress, mostly.

So it's likely you'd need a preselector to drive down the unwanted
overloading signals; possibly you'll hear more then on the frequency
you're tuned to.

Alternatively your outdoor antenna can be a low noise one, and give
you an advantage you don't get indoors. Ie. designed not to pick
up signals and noise you don't want to hear. Whether this is dimmer
noise from neighbors or power pole insulators breaking down, or
some local broadcaster, depends on your situation.

I use active antennas outdoors and phase them to produce nulls,
chiefly on MW. Nulling SW signals that are not locally produced
is difficult by phasing though, unless you have a huge number of
elements to produce an extended null.
--
Ron Hardin


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

Ron Hardin wrote:

My general impression of modern receivers is that they're already really
sensitive. You get more signal and equally more noise from a bigger
antenna, so you're not ahead once you're above the internal noise of
the receiver, which is what is low in modern receivers and so you
don't see much advantage once you're beyond the minimum antenna.

On the other hand, you get increased intermodulation and overload
from other signals you're not meaning to listen to, and that's
something modern receivers are not designed to suppress, mostly.

So it's likely you'd need a preselector to drive down the unwanted
overloading signals; possibly you'll hear more then on the frequency
you're tuned to.

Alternatively your outdoor antenna can be a low noise one, and give
you an advantage you don't get indoors. Ie. designed not to pick
up signals and noise you don't want to hear. Whether this is dimmer
noise from neighbors or power pole insulators breaking down, or
some local broadcaster, depends on your situation.

I use active antennas outdoors and phase them to produce nulls,
chiefly on MW. Nulling SW signals that are not locally produced
is difficult by phasing though, unless you have a huge number of
elements to produce an extended null.

A passive pre-selector is almost mandatory when using a good external
antenna with a sensitive portable like the SW77. I had to do this with
my '2010'. Otherwise the bands were full of spurious signals
(intermod's).


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I live in a penthouse on top of a six-floor building in middle of
noisy San Juan Puerto Rico and I have tried using an outdoor wire
antenna on my SW 77 strung across my terrace. I must say that the whip
is a whole lot better because it doesn't amplify all the snaps,
crackles and pops. Try using the outboard wire antenna and extend it
out from a window. I do that sometimes and let it hand down. I find
that works great. I am able to receive Indonesia, Western Sahara,
Brazil, Peru and New Zealand from my QTH. I think a regular wire
antenna with ground and all overloads this overly sensitive rx. Let's
us know how you make out.