Greg 43AX005Q: What is the Stoner PRO-40 SSB?
by AX05 » Fri Dec 28, 2007 7:34 am
Q: What is the Stoner PRO-40 SSB?
A: The BEST SSB CB radio ever made (NOT the editors opinion!;-)
A number of unusual engineering techniques were employed in the PRO-40.
To eliminate crossmodulation interference from adjacent channels, Stoner avoided the conventional transistor r.f. amplifier/mixer technique used in virtually ALL CB receivers even today. In fact, no r.f. stage is used at all and a Schottky diode mixer is employed, similar to that used in commercial SSB equipment. With no amplifying stages in the front end which could be overdriven by strong signals, the receiver uses dual cascaded crystal filters for extraordinary selectivity. Reception of unwanted sideband is totally suppressed. This allows the radio to be used within 100ft. of another station without harmful interference. Adjacent channel rejection is greater than 90dB, and crossmodulation rejection greater than 120dB.
AM heterodyne can be eliminated by the “Whistlestop” passband audio filter, which can also be used to “peak” audio, helping separate stations on the same channel. In addition, dual time constant “NB1” and “NB2” noise blankers are provided.
The PRO-40 employs a built-in speech processor which creates a unique SSB tailored audio envelope and “talk power” without distortion or the need for an amplified microphone. The radio was factory equipped with an Astatic GD-104.
What does it sound like on the air? In the 11m environment full of “peaked and tweaked” radios, overmodulated signals and excessive background, the Stoner shines, always spurring unsolicited comments on the “sound”. “..What kind of radio are you on?….What kind of mic are you using?…very pleasant sound…easy to listen to…easy on the ear…broadcast quality…sounds real smooth…very crisp and clear…..” When you key a Stoner, people listen.
Channel selection is controlled by a custom “Nitron” chip interfaced with scan-actuating pushbutton switches. The radio features a true frequency counter readout active on transmit and receive.
Fine tuning the PRO-40 is a real pleasure with the wide range 10-turn clarifier and large dial for smooth response.
Another interesting feature is the unique discriminator type SWR meter, unseen in typical CB radios, indicating the optimum transmitting frequency of the antenna without calibration. The meter works much the same as the tuning indicator on an FM receiver. Deviation from the centerline of the meter indicates antenna mistuning and whether the antenna is high or low of the operating frequency.
Although the PRO-40 does NOT offer an AM or FM mode, a provision is made to allow interconnecting antenna and power to a typical external AM/FM CB radio, to allow using both radios on the same antenna without swapping antenna leads by simply depressing the “AM” button. This passes the AM/FM signal through the PRO-40 internal multi-stage TVI filter and frequency counter for accurate display of the external radio output.
In 1977-80, even with contenders such as Cobra, Midland and Browning all vying for the high end CB market with impressive models such as the 2000GTL, 78-999 and Golden Eagles, the Stoner PRO-40 SSB stood out as the 11m DX Sidebander dream radio.
: according to : http://www.dxring.net/stoner/
Certainly has some impressive specs even if it looks like a modern TRAM D201!!
Last edited by AX05 on Tue May 13, 2008 12:24 pm, edited 2 times in total.
AX05
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