|Adept Instruments - Attenuators|
|"Fox Hunting" / Radio Transmitter Tracking Accessories|
|In Radio Direction Finding, at the receiving end, the signal levels can
vary significantly. When the transmitter is near the receiver, the signal level is so high
that the receiver's input circuits are overdriven. For direction finding to be effective, a
receiver's circuits must be kept within normal operating levels. Strong signals must be
attenuated before they enter the receiver's front end. Some receivers have a built-in
attenuator function. It may have just one selectable level (usually about 10 or 20 dB), or
it may have several levels. If the receiver does not have several attenuator levels built
in, and most don't, you'll almost surely need an external attenuator to further cut down the
signal at close range.
|A fixed value attenuator offers a simple and low cost solution for attenuating a strong signal. Momentarily disconnect the antenna coax from the receiver, connect the attenuator, then reconnect the coax. The procedure is almost as fast as throwing a switch. A good value for a single attenuator is 30dB. By the time a signal is too strong for effective direction finding, addition of 30 dB should be enough to knock it back down to a useable level. Two of the attenuators in series will attenuate the input by 60 dB.|
|Model: 30dB-ATTN||Fixed Attenuator 30 dB BNC Male, BNC Female.||$ 16.79|
|This 30dB-Attenuator is suitable for instrument-grade measurements.|
|Active Offset Attenuator
If a receiver's input signal is too strong, the front end circuitry will be overloaded, and a significant amount of signal gets into the receiver through its unshielded plastic case. The signal strength appears to be the same from all directions. An Offset Attenuator can solve these problems.
The Adept Offset Attenuator includes a 4 MHz local oscillator with a sine wave output voltage, adjustable from near zero to maximum. This signal is mixed with the input signal using a simple diode mixer. Two new frequencies are created, the input signal plus 4 MHz, and minus 4 MHz. Adjusting the level of the oscillator will also adjust the levels of the new frequencies. The receiver is tuned to one of the new frequencies, which allows the receiver's input signal strength to be adjustable from full strength to near zero. This emulates an attenuation function. The original input signal stays the same, but it is 4 MHz away from the receiver's input frequency, and virtually none of the signal that penetrates the unshielded plastic case can have any effect. For more information see the Instructions and Data Sheet.
Attenuator BNC Male, BNC Female.
Ready to Use with CR2032 Lithium Battery Installed.
|Click Here for Shielded and Partial Kit Versions of this Product.|
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