Antenna Confusion
 

I've had my R75 for about 2 years now.
I purchased an Antenna Supermarket dipole, the one with the sealed traps,
for the radio.
Then I went and had the Kiwa mods done.
All in all, a very nice setup. And like everyone says, it's great at
Utility listening.
But lately, I've been wanting to dig out more of those tough foreign country
broadcast signals.
Last night was absolutely horrible for listening to foreign stations. Only
received a
few of the strongest ones that were beamed at N. America. So I figured I'd
try something
different. I took a piece of speaker wire, about 25' long, twisted the 2
wires together at each end, stuck
one end into the R75 longwire input, and threw the rest out of my basement
window (yes my radio is in the
basement). So, I took the remaining 15 feet of wire and looped it into a
bush along the side of my house.
It must be all of 5' off the ground.
Back inside I go, not expecting much from the wire. I tuned to a station I
knew I could receive and voila!
It came in nicely. I switched back and forth from the wire to the dipole
and no difference. Hmmmm, strange!
I tuned in a few other stations that were weaker and again, no difference.
Amazing!
Did I waste my money on the Dipole antenna? I can't imagine what 200' of
wire strung up 25' high in my trees
will sound like.
Now I'm wondering if the Dipole has any advantages over the long wire.
Could some kind soul please explain what is happening?
Any recommendations?
Is there a "SW Antennas for Dummies" site somewhere?
Thank you,
Lenny

"Lenny" wrote:
I've had my R75 for about 2 years now.
I purchased an Antenna Supermarket dipole, the one with the sealed traps,

The traps make the dipole resonant at specific frequencies. On those
frequencies the dipole will exhibit the normal broadside pattern. Trap
dipoles tend to have narrow resonant bandwidths at the lower frequencies

Last night was absolutely horrible for listening to foreign stations.
Only
received a few of the strongest ones that were beamed at N. America.

Probably just propagation.

I took a piece of speaker wire, about 25' long, twisted the 2
wires together at each end, stuck
snip
I switched back and forth from the wire to the dipole
and no difference. Hmmmm, strange!
I tuned in a few other stations that were weaker and again, no difference.

Quantify that. No difference in what your ears heard or no difference on the
"S" meter.

If the "S" meter reads the same on the dipole as on the 25' low wire,
something is wrong. Check you coax connections.

However, it's not unusual for a poor antenna to produe a similar "sounding"
signal as a good antenna. Your dipole should be picking up more signal than
the short wire, but it's also picking up more noise. So the "signal-to-noise
ratio" your ears hear will often be the same.

Did I waste my money on the Dipole antenna? I can't imagine what 200' of
wire strung up 25' high in my trees
will sound like.
Now I'm wondering if the Dipole has any advantages over the long wire.
Could some kind soul please explain what is happening?

The trap dipole will have a predictable pattern on its resonant frequencies.
A 200' wire will have different patterns on different frequencies (not
necessarily a bad thing). I personally don't think it makes sense to spend a
lot of money on a commercial trap dipole for SWL'ing. A random wire (doesn't
have to be 200' long) is a very good choice. Signal-to-noise ratio is what
determines readability, not absolute signal pickup.

Art Harris N2AH

If you don't mind the extra noise, I'd go with a longwire.

"Arthur Harris" wrote in message
. net...
"Lenny" wrote:
I've had my R75 for about 2 years now.
I purchased an Antenna Supermarket dipole, the one with the sealed
traps,

The traps make the dipole resonant at specific frequencies. On those
frequencies the dipole will exhibit the normal broadside pattern. Trap
dipoles tend to have narrow resonant bandwidths at the lower frequencies

Last night was absolutely horrible for listening to foreign stations.
Only
received a few of the strongest ones that were beamed at N. America.

Probably just propagation.

I took a piece of speaker wire, about 25' long, twisted the 2
wires together at each end, stuck
snip
I switched back and forth from the wire to the dipole
and no difference. Hmmmm, strange!
I tuned in a few other stations that were weaker and again, no
difference.

Quantify that. No difference in what your ears heard or no difference on
the
"S" meter.

If the "S" meter reads the same on the dipole as on the 25' low wire,
something is wrong. Check you coax connections.

However, it's not unusual for a poor antenna to produe a similar
"sounding"
signal as a good antenna. Your dipole should be picking up more signal
than
the short wire, but it's also picking up more noise. So the
"signal-to-noise
ratio" your ears hear will often be the same.

Did I waste my money on the Dipole antenna? I can't imagine what 200'
of
wire strung up 25' high in my trees
will sound like.
Now I'm wondering if the Dipole has any advantages over the long wire.
Could some kind soul please explain what is happening?

The trap dipole will have a predictable pattern on its resonant
frequencies.
A 200' wire will have different patterns on different frequencies (not
necessarily a bad thing). I personally don't think it makes sense to spend
a
lot of money on a commercial trap dipole for SWL'ing. A random wire
(doesn't
have to be 200' long) is a very good choice. Signal-to-noise ratio is what
determines readability, not absolute signal pickup.

Art Harris N2AH

"Lenny" wrote in message ...
I've had my R75 for about 2 years now.
I purchased an Antenna Supermarket dipole, the one with the sealed traps,
for the radio.
Then I went and had the Kiwa mods done.
All in all, a very nice setup. And like everyone says, it's great at
Utility listening.
But lately, I've been wanting to dig out more of those tough foreign country
broadcast signals.
Last night was absolutely horrible for listening to foreign stations. Only
received a
few of the strongest ones that were beamed at N. America. So I figured I'd
try something
different. I took a piece of speaker wire, about 25' long, twisted the 2
wires together at each end, stuck
one end into the R75 longwire input, and threw the rest out of my basement
window (yes my radio is in the
basement). So, I took the remaining 15 feet of wire and looped it into a
bush along the side of my house.
It must be all of 5' off the ground.
Back inside I go, not expecting much from the wire. I tuned to a station I
knew I could receive and voila!
It came in nicely. I switched back and forth from the wire to the dipole
and no difference. Hmmmm, strange!
I tuned in a few other stations that were weaker and again, no difference.
Amazing!
Did I waste my money on the Dipole antenna? I can't imagine what 200' of
wire strung up 25' high in my trees
will sound like.
Now I'm wondering if the Dipole has any advantages over the long wire.
Could some kind soul please explain what is happening?
Any recommendations?
Is there a "SW Antennas for Dummies" site somewhere?
Thank you,
Lenny

Several years ago I lived in Sacramento and put up the Sloper antenna
- it was mounted on my tv antenna mast about 10-feet above roof level
and ended on top of my 6-foot fence. I had is installed on my Grundig
650. It was professionally installed by an antenna dealer. On some
frequencies, it did better than the internal whip antenna, and on
other frequencies the internal whip did better. And on some
frequencies the signal was the same. At no frequency did the Sloper
antenna give a BIG difference in signal level compared to the internal
whip, but on the tropical bands, it made enough of a difference to
hear a couple stations that were hard to hear using the whip. But
even then, on a slight difference.

A longwire or inverted-L doesn't have to be noisier than balanced
antennas such as a dipole. It's matter of how the coax shield is
grounded/decoupled from the antenna. Here's one way to do it:

http://www.anarc.org/naswa/badx/ante...e_antenna.html




Maximus wrote:

If you don't mind the extra noise, I'd go with a longwire.

"Arthur Harris" wrote in message
. net...
"Lenny" wrote:
I've had my R75 for about 2 years now.
I purchased an Antenna Supermarket dipole, the one with the sealed
traps,

The traps make the dipole resonant at specific frequencies. On those
frequencies the dipole will exhibit the normal broadside pattern. Trap
dipoles tend to have narrow resonant bandwidths at the lower frequencies

Last night was absolutely horrible for listening to foreign stations.
Only
received a few of the strongest ones that were beamed at N. America.

Probably just propagation.

I took a piece of speaker wire, about 25' long, twisted the 2
wires together at each end, stuck
snip
I switched back and forth from the wire to the dipole
and no difference. Hmmmm, strange!
I tuned in a few other stations that were weaker and again, no
difference.

Quantify that. No difference in what your ears heard or no difference on
the
"S" meter.

If the "S" meter reads the same on the dipole as on the 25' low wire,
something is wrong. Check you coax connections.

However, it's not unusual for a poor antenna to produe a similar
"sounding"
signal as a good antenna. Your dipole should be picking up more signal
than
the short wire, but it's also picking up more noise. So the
"signal-to-noise
ratio" your ears hear will often be the same.

Did I waste my money on the Dipole antenna? I can't imagine what 200'
of
wire strung up 25' high in my trees
will sound like.
Now I'm wondering if the Dipole has any advantages over the long wire.
Could some kind soul please explain what is happening?

The trap dipole will have a predictable pattern on its resonant
frequencies.
A 200' wire will have different patterns on different frequencies (not
necessarily a bad thing). I personally don't think it makes sense to spend
a
lot of money on a commercial trap dipole for SWL'ing. A random wire
(doesn't
have to be 200' long) is a very good choice. Signal-to-noise ratio is what
determines readability, not absolute signal pickup.

Art Harris N2AH


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I can't imagine what 200' of
wire strung up 25' high in my trees
will sound like.

It would sound wondeful Lenny and cheap also.:-) Do it, you'll see what I
mean.

Several years ago I lived in Sacramento and put up the Sloper antenna

Huh? What 'kind' of sloper? I have the Alpha Delta DX sloper and if that's
the one you're talking about, something isn't hooked up right if you're just
getting those results. Just thought I'd throw that in the ring.:-)

OK, good suggestions all.
Thanks.
But more questions.
If I connect the long wire to a coax feed, will it perform better than my
Antenna Supermarket Dipole?
And how does one connect a long wire to a coax?
Lenny


"Dxluver" wrote in message
...
I can't imagine what 200' of
wire strung up 25' high in my trees
will sound like.

It would sound wondeful Lenny and cheap also.:-) Do it, you'll see what
I
mean.

And what's the best wire to use?
Braided or unbraided?
Lenny


"Dxluver" wrote in message
...
I can't imagine what 200' of
wire strung up 25' high in my trees
will sound like.

It would sound wondeful Lenny and cheap also.:-) Do it, you'll see what
I
mean.

I don't have the antenna anymore since I have moved, but I believe it
was the Alpha Delta sloper. If not, it was a major brand purchased
from Universal Radio. It was NOT the longest sloper offered, but
rather the more compact sloper - probably more like 60 feet in length.
The antenna was installed properly and it was hooked up correctly.
Had the original Grundig connector, proper coax leadin, and like I
said, was installed by an experienced antenna installer.

Huh, don't know what to say other than I'm not an *experienced antenna
installer*(meaning I don't get nor have I, got paid to put up an antenna) but
mine has logged manyyyyy a stations for years. Interesting. Sorry about your
bad luck, and I really mean that Gary.

On SW,
received stations all over the dial, from all over the world. And
even thought it didn't have a sync detector, would still pick up clear
signals that I could NOT receive on my Sony 2010, both using their
internal whip antenna, expecially when there was strong interference
on BOTH sides of the desired signal. It had great selectivity. I
could usually use the 6.0 filter position and seldom had to switch to
the "medium" filter position, which was actually the 6.0 filter with
audio tailored to get rid of hets and other types of interference


Gee, sounds like the best radio ever made. Maybe you can get you another one.
I'll stick with my Hammarlunds. ;-)