IMPROVES THE SENSITIVITY OF ANY VINTAGE HF RECEIVER
Price $35.00
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The
BBPV preamp is intended to be installed inside of your vintage receiver.
The ability of a radio receiver to receive weak signals is affected by two things, atmospheric and man made noise, and the noise figure of the receiver. Noise Figure is a technical term that represents the amount of the noise produced by the receiver, that the signal must overcome to be heard. The lower, the better.
Atmospheric noise is affected mostly by local weather and weather conditions at the location of the station you are trying to receive. It is very difficult to reduce this kind of noise. Man made noise refers to noise from electrical appliances, ignition noise from cars, florescent lights, and other things like that.
The noise figure of a receiver is determined by the first stage, usually the RF amplifier, or mixer stage. Noise figure is expressed in decibels, or db. Typical receivers have noise figures of 10 to 12 db which is not really very good. A receiver with a 12 db noise figure is acceptable when it is the atmospheric or man made noise that is limiting the ability to receive a weak station, but when noise is low, and it often is, a preamp can help. What causes older receivers to have high noise figures is the technology when they were designed, and misalignment of the RF tuning. The tracking of the local oscillator and RF tuning is never perfect. Most tube receivers have poor sensitivity on the higher frequencies so the improvement will be very noticable above 10MHz to 15 MHz. Also noise is lower on the higher frequencies.
The BBPV Broadband Preamp connects in the antenna lead inside the receiver. It has no lossy circuits that the signal must go through to reach the amplifier. It has a 2.5 to 3 db noise figure and 10 db of gain. That's more than 3 S units. When noise is low, signals that don't move the S meter and can barely be heard, sometimes become 100% readable. 10 db of gain is enough for a very noticeable improvement but not enough to cause overloading at most locations. It is effective from below the AM broadcast band up to 30MHz and above. It is powered from the receiver 6.3V or 12.6V filament supply. It cannot be powered by receivers that don't have a power transformer. Model BBP-.5-30 must be used. Velcro is included for mounting.