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BBP-1020 2 STAGE SHORTWAVE HAM RADIO HF RECEIVER PREAMP
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All Of My Auctions Include A Money Back Satisfaction Guarantee.
The ability to receive weak stations is determined by two things, the receiver noise figure, and the amount of atmospheric and man made noise present. Noise figure is a technical term that represents the amount of noise produced by the receiver, that the signal must overcome to be heard. The lower, the better. A low noise broadband preamp improves the sensitivity of any HF receiver by lowering the overall noise figure, including older vintage receivers and even modern receivers like the Kenwood R-5000 and the Icom R71 and R75. Another way to think of it is that adding a low noise preamp to your receiver is the same as increasing the length or efficiency of your antenna.
Modern HF receivers used used by amateur radio operators and shortwave listeners like the Kenwood R-5000 and the Icom R71 and R75, have less than optimum sensitivity because of the design of there front end circuitry. By front end I mean the first receiver circuitry that the signal goes through. Because of loses in their front end circuitry, typical receivers have noise figures of 10 to 12 db and higher which is really not very good. The input of modern receivers is no longer tuned to individual stations, the front end circuitry typically consists of a bank of bandpass filters, which cover the frequency range of 100KHz to 30MHz, and diode switches to switch in the appropriate filter for the frequency you want to receive. Band pass filters have higher loss than a circuit tuned to a single frequency. There are two diode switches for each filter. There are also resistors that supply the current to the diodes. The signal must go through two diode switches and a band pass filter before it gets to the first amplifier stage. There may be other circuit elements depending on the receiver manufacturer.
All of that circuitry introduces loss of several db. So even if the first RF amplifier has a low noise figure, which is what determines sensitivity, the overall noise figure is degraded by the circuitry that precedes it. The sensitivity of those receivers is considered acceptable because much of the time the atmospheric and man made noise is the limiting factor in the ability to receive a weak station. However there are often times when noise is low, and the receiver noise figure is the limiting factor. Also atmospheric and man made noise decreases as frequency increases so on the higher bands, the noise is very often low. It is the times when noise is low that a low noise preamp can help. For a shortwave listner it can make the difference in identifying a station.
An easy test that will determine if a preamp can help you, is to tune your receiver to a frequency where there is no station, only noise. Then disconnect the antenna right at the receiver antenna connector. If there is a big reduction in the noise, a preamp cannot help you on that frequency. The noise you hear is being picked up by the antenna. If there is little or no reduction in noise, a preamp will help. The noise you hear is being genegated in the receiver. What you would like is that there be a big reduction in noise when you disconnect the antenna, on all frequencies. In that case the receiver is not limiting the sensitivity. You need to do this on several frequencies and at different times of the day. Atmospheric and man made noise changes from time to time and day to day, and reduces as you go higher in frequency. A preamp is most likely to help on higher frequencies. As an example, my Kenwood R-5000 passes the test on 10MHz, but fails the test on 15MHz and above. In other words at 10MHz a preamp will not help but at 15MHz and above it will. Since I know that my R-5000 can be improved on some frequencies, why not use the preamp and be sure I always have optimum sensitivity on all frequencies.
Sometimes just a little lower noise figure or a little more gain can make the difference. The BBP-1020 is two stages of our BBP-.5-30 preamp. It has a noise figure of 2.5db and a gain of either 10db or 20db than. This combination of low noise figure and 10db or 20db gain will improve virtually any receiver. Because the amount of noise varies, it won't however improve every weak station 100% of the time. The frequency range is 500KHz to well over 30MHz. When the preamp is off, the antenna is passed through unaffected however you cannot transmit through it. UHF (SO-239) connectors are used for the antenna and receiver. A wall plug-in power supply is also included. This is new and I am the manufacturer. More information is available at:
http://www.electronicspecialtyproducts.com/bbp1020.html
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