Superadio II question
 

Just picked up a Super II for $10 today. The FM antenna is missing the last
segment and I'm curious if anyone has a suggestion as to a replacement. Even in
its 'shorter' condition, I can still pick up a hard-to-get FM station. Does
anyone have a RadioShack substitution idea?

The Date Code is 6140C.....anyone know what it means....the 40th week of 1961?

The serial number is 192590.....anyway of correlating that to a date?

Any information you can provide will be appreciated. I've visited many
Superadio websites but didn't find one that gave date codes.

thanks

elfa

BTW....the sound is incredible! It beats all the rest of my portables by a
mile.

Attach a wire the length of the last segment. It might not be pretty, but
I'll bet it would work S.

In article , Warpcore says...

Attach a wire the length of the last segment. It might not be pretty, but
I'll bet it would work S.


Actually....I have no idea how long the missing segment (or segments) are but
I'm thinking that with 24 inches still there, that's probably enough for FM.

Amazingly, I have yet to find a website that explains FM whip antennas and the
best way to use them.

I have a Zenith TransOceanic and its manual states that its combination SW/FM
whip should be pulled out only 18 inches and angled at 45 degrees to the
horizontal for best reception when using FM. Maybe what I've got left is enough
and a whip any longer wouldn't make reception any better.

elfa

elfa wrote:

Actually....I have no idea how long the missing segment (or segments) are but
I'm thinking that with 24 inches still there, that's probably enough for FM.

Amazingly, I have yet to find a website that explains FM whip antennas and the
best way to use them.

A quarter-wave length on the FM band is about 30", +/- depending on the
actual frequency. I'd aim for that.

-Bill

In article , --exray-- says...

elfa wrote:

Actually....I have no idea how long the missing segment (or segments) are but
I'm thinking that with 24 inches still there, that's probably enough for FM.

Amazingly, I have yet to find a website that explains FM whip antennas and the
best way to use them.

A quarter-wave length on the FM band is about 30", +/- depending on the
actual frequency. I'd aim for that.

-Bill


Thanks Bill....that's the first piece of information I've ever heard on FM whip
antennas.

elfa

elfa wrote:
In article , --exray-- says...

elfa wrote:


Actually....I have no idea how long the missing segment (or segments) are but
I'm thinking that with 24 inches still there, that's probably enough for FM.

Amazingly, I have yet to find a website that explains FM whip antennas and the
best way to use them.

A quarter-wave length on the FM band is about 30", +/- depending on the
actual frequency. I'd aim for that.

-Bill



Thanks Bill....that's the first piece of information I've ever heard on FM whip
antennas.

elfa

Then maybe if I expound others will chime in with their info.
Generally you can consider a FM whip as a quarter-wave vertical or
'ground plane' type antenna. You can go out and measure the one on your
car to get a good idea of the consistency of this length.
A quarter-wave vertical gives a low input impedance, theoretically
around 30 ohms but in practice a bit higher.
A key part of the quarter-wave vertical system is the ground plane. In
a portable radio its not so easy to establish a good ground plane but
thats not a big issue. Portable sets are typically most interested in
local signals and you can adjust the whip around if the radiation angle
or length ain't book spec.
If you were doing the same for an outdoor fixed antenna you'd want to
focus on the ground plane to obtain uniform low angle omni-directional
coverage.
FM broadcast stations these days tend to use circular polarization more
often than not. That tends to minimize the differences between a
horizontal receive antenna (like a dipole) and a vertical antenna (like
a whip). Some old timers still transmit with one or the other, or a
combination of the two, but circular tends to provide better coverage
given that FM rcv antennas may range from a Walkman headphone cord to a
new Lexus driving up a steep hill.
I'm still a bit miffed about the TO instructions for 18"...maybe their
input is high impedance and the 18" configuration would certainly send
the impedance to the high end of the scale???.
The classic formula for a quarter-wave vertical/whip is 264 divided by
Megahertz, the result is in feet. 98 MHz would give 2.69 feet or 32.3
inches. The diameter etc have a bit of effect on the formula but its
close enough for hacking around with.
So there. Now you have some ammunition to play with.

-Bill

In article , --exray-- says...

elfa wrote:
In article , --exray-- says...

elfa wrote:


Actually....I have no idea how long the missing segment (or segments) are but
I'm thinking that with 24 inches still there, that's probably enough for FM.

Amazingly, I have yet to find a website that explains FM whip antennas and the
best way to use them.

A quarter-wave length on the FM band is about 30", +/- depending on the
actual frequency. I'd aim for that.

-Bill



Thanks Bill....that's the first piece of information I've ever heard on FM whip
antennas.

elfa

Then maybe if I expound others will chime in with their info.
Generally you can consider a FM whip as a quarter-wave vertical or
'ground plane' type antenna. You can go out and measure the one on your
car to get a good idea of the consistency of this length.
A quarter-wave vertical gives a low input impedance, theoretically
around 30 ohms but in practice a bit higher.
A key part of the quarter-wave vertical system is the ground plane. In
a portable radio its not so easy to establish a good ground plane but
thats not a big issue. Portable sets are typically most interested in
local signals and you can adjust the whip around if the radiation angle
or length ain't book spec.
If you were doing the same for an outdoor fixed antenna you'd want to
focus on the ground plane to obtain uniform low angle omni-directional
coverage.
FM broadcast stations these days tend to use circular polarization more
often than not. That tends to minimize the differences between a
horizontal receive antenna (like a dipole) and a vertical antenna (like
a whip). Some old timers still transmit with one or the other, or a
combination of the two, but circular tends to provide better coverage
given that FM rcv antennas may range from a Walkman headphone cord to a
new Lexus driving up a steep hill.
I'm still a bit miffed about the TO instructions for 18"...maybe their
input is high impedance and the 18" configuration would certainly send
the impedance to the high end of the scale???.
The classic formula for a quarter-wave vertical/whip is 264 divided by
Megahertz, the result is in feet. 98 MHz would give 2.69 feet or 32.3
inches. The diameter etc have a bit of effect on the formula but its
close enough for hacking around with.
So there. Now you have some ammunition to play with.

-Bill


Thanks again....I'll copy and paste this to a document. Question....what about
angling the antenna...ie, not vertical but maybe at a 45 degree angle. I
mention this as my Zenith Oceanics manual recommends it. And the manual also
says to only pull the antenna out about 16 inches.

elfa

elfa wrote:


Thanks again....I'll copy and paste this to a document. Question....what about
angling the antenna...ie, not vertical but maybe at a 45 degree angle. I
mention this as my Zenith Oceanics manual recommends it. And the manual also
says to only pull the antenna out about 16 inches.

elfa

I'm gonna answer that with 'do whatever works'. VHF (FM) reception
conditions can vary wildly from one side of the room to the other. When
the TOs were made there was no circular polarization so that advice may
have lost a bit of creedence over the years.
Still dunno about the 16". I have a TO 3000-1 squirreled away, next
time I find it and dust it off I'll try that.
-BM

Attach a wire the length of the last segment. It might not be pretty, but
I'll bet it would work .

Maybe an aluminum knitting needle will work. It can fit down into the hollow
whip.

Bill, K5BY

In article , WShoots1 says...

Attach a wire the length of the last segment. It might not be pretty, but
I'll bet it would work .

Maybe an aluminum knitting needle will work. It can fit down into the hollow
whip.

Bill, K5BY

Tried it already with a short piece of whip antenna from my junk box. There's
something inside the last extension that prevents it from going in very far.

elfa