Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.
I have a GE 40 channel cb and it has Double Super Hetrodyne.
Brian - Las Vegas

Brian,

Without going into the technical aspects, I'll simply say that
a double-conversion superheterodyne receiver offers improved
sensitivity and selectivity over a single-conversion superhet.
In the early days of CB (ie, the 1960s), the majority of CB
sets used a single-conversion receiver, while some of the high-
end models used double-conversion. As CB became more populer
in the late 1960s and more stations came on the air, it became
necessary to improve receiver selectivity to reduce the problem
of "bleedover" from adjacent channels. With that in mind, the
majority of CB manufacturers began using double superhets for
even their "cheap" radios, and from then on it became standard
practice.

If you would like to learn about the technical reasons for all
of this, pay a visit to your public library and look for an
ARRL Radio Amateur's Handbook, and read up on receiver theory
and design.

73,
Dean K5DH


In article ,
says...

Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.
I have a GE 40 channel cb and it has Double Super Hetrodyne.
Brian - Las Vegas

Since citizens band is operating at about 27 MHz, the standard i.f. of .455
MHz allows an image of twice the i.f. frequency (.91 MHz). This image is
not rejected by the tuned circuits of the cb rig. So, double conversion is
used. In this specific case, the selectivity is not increased, but the
image rejection is. Often the first i.f. is in the 5 to 10 MHz range.
Recently, with the use of low noise mixers, the first i.f. can be at 40 MHz
or higher, which provides excellent image rejection.

Bottom line is that most cb radios that are average or better use double
conversion. In the case of your GE unit, the marketing department decided
to add a little hype to an rather ordinary cb unit and called it a Double
Super Hetrodyne. Is your radio a special radio? No. Is it worth more? No.

Colin K7FM

the first if is on 10.7 , and use commercial ceramic filters auns the second
one is on 455 khz and also use ceramic filters !!! a simply question of
cost.... f4ere serge.
"Captain Crane" a écrit dans le message de news:
...
Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.
I have a GE 40 channel cb and it has Double Super Hetrodyne.
Brian - Las Vegas

"Captain Crane" wrote in message
...
Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.
I have a GE 40 channel cb and it has Double Super Hetrodyne.
Brian - Las Vegas


The straight answer? Double conversion is used to reduce images.


It does nothing for sensitivity or selectivity in itself; and it probably
decreases dynamic range and makes the receiver more prone
to spurious responses.

Pete

Captain Crane
wrote in message ...
Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.
I have a GE 40 channel cb and it has Double Super Hetrodyne.
Brian - Las Vegas


My question is what the heck does this have to do with
AMATEUR BOATANCHORS?
There are dozens of CB newsgroups out there, maybe hundreds,
of course no one there could have answered this question... But still.

I know, now someone is going to say I'm being rude to new comers...


Ron

On Wed, 01 Feb 2006 23:37:19 GMT, " Ron in Radio Heaven"
wrote:

Captain Crane
wrote in message ...
Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.
I have a GE 40 channel cb and it has Double Super Hetrodyne.
Brian - Las Vegas


My question is what the heck does this have to do with
AMATEUR BOATANCHORS?
There are dozens of CB newsgroups out there, maybe hundreds,
of course no one there could have answered this question

Maybe that's why he asked here.

Or then again, a radio is a radio. And probably some folks here maybe
even learned something too.

73
Gary K4FMX

.. But still.

I know, now someone is going to say I'm being rude to new comers...


Ron

In article , SeaView-
(known to some as Captain Crane) scribed...

Hi, Does anyone know What Double Super Hetrodyne does in a CB radio.

snippety

Yes. It gives the marketing dweebs something to write about.

I have a GE 40 channel cb and it has Double Super Hetrodyne.

There is a possibility -- a very weak one -- that this bizarre
market-speak means that the radio was designed with a double-conversion
receiver. It's impossible to say without seeing a schematic.

Why anyone would put that much effort and expense into a CB radio,
however, is beyond me. I think you're running into nothing more that
marketing buzzwords. "Double Super Heterodyne" certainly has no meaning
in the technical world.


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
http://www.bluefeathertech.com -- kyrrin a/t bluefeathertech d-o=t calm
"Salvadore Dali's computer has surreal ports..."

Dr. Anton T. Squeegee wrote:



There is a possibility -- a very weak one -- that this bizarre
market-speak means that the radio was designed with a double-conversion
receiver. It's impossible to say without seeing a schematic.

Why anyone would put that much effort and expense into a CB radio,
however, is beyond me. I think you're running into nothing more that
marketing buzzwords. "Double Super Heterodyne" certainly has no meaning
in the technical world.

I think it means something equivalent to "has ears and barks well into
the next county bubba 10-4 beep".

Okay, that was a nasty shot but there were indeed double-conversion rigs
back in the CB heyday. When every other trailer in the court was
running kilos of Bird-watts double talk conversion had its advantages.

We're 10-8 and on the side bubba 10-4? beep. Gotcha comin on. Beep.

I really don't know this lingo...I'm reading it off the side of a 1970s
beer mug....a cheap mug at that.

-Bill

"- exray -" wrote in message
...
Dr. Anton T. Squeegee wrote:

I think it means something equivalent to "has ears and barks well into
the next county bubba 10-4 beep".

Okay, that was a nasty shot but there were indeed double-conversion rigs
back in the CB heyday. When every other trailer in the court was
running kilos of Bird-watts double talk conversion had its advantages.

We're 10-8 and on the side bubba 10-4? beep. Gotcha comin on. Beep.

I really don't know this lingo...I'm reading it off the side of a 1970s
beer mug....a cheap mug at that.

-Bill

I assumed it meant double-conversion.

Pete