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do export radios have class ratings for the tx part ?

B

BOOTY MONSTER

Guest
do the export radios tx section have different class ratings like amps do ? exp. class c class b and class ab ? or are they a different class ?
thanks
 

most export radios like the rangers are class C biased
is ok but is for sure splash boxes
is likly less of a problem if you are using it mobil
more likly a issue if using as a base
 
all exports are class AB in ssb, maybe not the best regulated biasing but class AB
 
I agree with Bob.The Rangers at least are class AB with a bias adjustment pot for both the driver and finals. With the audio quality reports on SSB it is definately no class C splatter box.
 
bob85 and QRN

i am usally with you guys in your opinions
you are wrong this time for sure

(i am talking in reference to ranger export radios for i am not 100% sure on other makes and models,however seeing how as far as export radios go,generally speaking ranger radios are the better export radios)

simply ask Ranger direct or look at their specs
it is their lack of AB1 Biasing that makes them the splash boxes they are..
That being said...i also know from experience (whether is their base or mobil radios) they do indeed get out very well both locally and when skip is rolling in.

remember though AB1 Biasing is not required for a radio to get out fairly well..

HEY......... Who is is watching Daytona 500 today
 
as far as i know every ssb radio has biasing, if they were class c they would sound garbage on ssb just like any class C amp used on ssb,
the rangers certainly are biased, the parts are there in the schematic and in the radios in all versions i have seen, the older 2950 has fixed bias with thermal tracking on the finals while the 2950dx has presets to adjust the idle current like any ther export, they both use idle adjustment on the driver with tracking,
the only unusual thing with the old model is the lack of adjustment in the final stage but thats easy to get around also.
maybe you are mistaking the lack of final idle adjustment for a lack of a bias circuit but i can assure you its there visually and audibly in all rangers i have worked on.
 
Actually I will concede they MAY be class C on FM and AM because the finals are modulated in AM service and thus could be operated any class without splatter,similar to class C plate modulation of a tube TX. In SSB mode however they cannot be class C,spectral purity says so. How's that for meeting in the middle? ;)

KingCobra_CDX882 said:
HEY......... Who is is watching Daytona 500 today

Oooooppss!....................See Ya! :shock:
 
The only thing that makes a radio a "splash Box" is the tune that is done to it. With a correct alignment and conservative tune you will have a nice clean sounding radio that DOES NOT bleed 10 channels in every direction. When you listen to the wild wattage claims people make of their radio's 75% of them are splash boxes. Thats what you get when you try and squeeze every last watt from a pair of finals and run it at 140% modulation.
 
the link hamer gave is good but it is generalized and does not tell the whole story for rf.

all a.m. only cb radios are class c. this is fine, and there is no distortion because they are using high level modulation. the flywheel effect completes the missing cycle with no distortion. radios like the hr2510 that uses low level modulation must use biasing or there will be distortion.

this is standard for all a.m. equipment, not just cb's. if it uses high level modulation (like rci/galaxy) then the driver and final is class c (no bias). if it uses low level modulation it has to use biasing or distortion will result.

on a last note, all external amplifiers (unless used for f.m. operation) need to use biasing. they are configured as low level modulated amplifiers (modulated by the final in the radio) so there will be distortion if these amps are not using biasing.
 
richard,
i am not disputing what class the exports run in FM/AM i am talking about SSB where near full vcc is applied to the collectors and approx .6v is applied to the transistor bases,
i thought it was been claimed they have no forward bias in any mode which is not the case nor do i believe the lack of a bias circuit is what makes an export dirty.
 

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