Many listeners have two or more receivers, but only space for one antenna. Connecting receivers in parallel to one antenna gives a lot of problems. Most receivers are equipped with RF bandpass filters at the input. The receiver input impedance is only 50 ohms within the pass band of the filter. For frequencies higher or lower than the pass band, the impedance of the filter is mostly very low. This means that if both receivers are tuned to different frequencies (let's say one on 3.5 MHz, the other on 14 MHz), the signals for the receiver tuned to 3.5 MHz are short-circuited by the receiver tuned to 14 MHz and vice- versa. Connecting both receivers in parallel (for instance with the help of a "T" adaptor), can give therefore serious sensitivity loss. Another problem is oscillator radiation. The signals of all the oscillators in a receiver can be found also on the antenna input. These signals are low in level, not more than a few micro volts. But when connected in parallel, the oscillator spurious from one receiver is directly fed into the antenna input of the other receiver. Whistles, interference and even blocking can be the result.
Splitters
The only proper way to connect two or more receivers to one antenna is with a splitter. This device divides the energy delivered by the antenna equally over the receivers. But the receivers don't "see" each other: there is isolation. This means that oscillator signals from one receiver cannot reach the other receiver, and that even when one receiver behaves it selves as a short-circuit for the other receiver, the signal to the first receiver is not influenced. RF
Systems produces several types of splitters: passive for two receivers, active for up to 4 or 8 receivers.
Combiners
For those who are so lucky to have space for two antennas, for instance one vertical polarised, the other horizontal polarised, or one N-Z, the other E-W, the same problem occurs. If the antennas are connected in parallel, the signals received by one antenna are re-radiated by the other antenna and improvement in reception is marginal or even absent. The SP -1 splitter (shortwave) and the SP - 3 splitter (VHF-UHF) can be used as combiner. With a combiner, the signals of each antenna are fed to the receiver, but the antennas don't "see" each other, which prevents that the signals of one antenna are re-radiated by the other. Combining antennas can give tremendous improvement in reception.
Amplifiers
In some situations amplification of antenna signals is necessary, for instance with low- efficiency antennas or when the receiver is not sensitive enough. Antenna amplifiers must have extremely high specifications, in order not to influence the receiver specifications. RF Systems produces such an amplifier, covering long- medium- and shortwave: the WA - 50.
* SP - 1 splitter/combiner
Passive, for two receivers on one antenna or 2 antennas on one receiver. Frequency range : 50 kHz - 50 MHz. Impedance 50 Ohms, very low loss
* SP - 2 splitter
Housed in a metal cabinet, this passive splitter makes it not only possible to connect two receivers to one antenna, but is also equipped with a step attenuator (0 to - 40 dB) to prevent receiver overload. A built-in medium wave suppression filter can be switched into the antenna circuit. This makes it possible to listen with full sensitivity on long- and shortwave without interference from strong medium wave stations. A built-in antenna switch makes it possible to connect the receiver(s) to two different antennas with the flick of a switch. The attenuator, medium wave suppression filter and antenna switch make the SP - 2 also ideally suited for the use with just one receiver.
Frequency range 50 kHz - 50 MHz. Impedance 50 Ohms.
* SP - 3 splitter/combiner for scanners
Passive, for two receivers on one antenna or two antennas on one receiver. Frequency range: 10 MHz - 2500 MHz. Impedance 50 Ohms, ultra low loss, BNC connectors.
* DA - 4 active splitter/distribution amplifier
Up to 4 receivers without signal loss on one antenna. Housed in metal cabinet.
Frequency range 10 kHz - 50 MHz. Very high isolation between the receivers. Dynamic range > 125 dB, very high intercept points.
* DA - 8 active splitter/distribution amplifier
Up to 8 receivers without signal loss on one antenna. Housed in metal cabinet.
Frequency range 10 kHz - 50 MHz. Very high isolation between the receivers. Dynamic range > 125 dB, very high intercept points.
* WA - 50 antenna amplifier
Broadband amplifier for the 50 kHz - 50 MHz frequency range. 10 dB gain, 50 ohms in- and output impedance. Low noise, very high intercept points.
Splitters
The only proper way to connect two or more receivers to one antenna is with a splitter. This device divides the energy delivered by the antenna equally over the receivers. But the receivers don't "see" each other: there is isolation. This means that oscillator signals from one receiver cannot reach the other receiver, and that even when one receiver behaves it selves as a short-circuit for the other receiver, the signal to the first receiver is not influenced. RF
Systems produces several types of splitters: passive for two receivers, active for up to 4 or 8 receivers.
Combiners
For those who are so lucky to have space for two antennas, for instance one vertical polarised, the other horizontal polarised, or one N-Z, the other E-W, the same problem occurs. If the antennas are connected in parallel, the signals received by one antenna are re-radiated by the other antenna and improvement in reception is marginal or even absent. The SP -1 splitter (shortwave) and the SP - 3 splitter (VHF-UHF) can be used as combiner. With a combiner, the signals of each antenna are fed to the receiver, but the antennas don't "see" each other, which prevents that the signals of one antenna are re-radiated by the other. Combining antennas can give tremendous improvement in reception.
Amplifiers
In some situations amplification of antenna signals is necessary, for instance with low- efficiency antennas or when the receiver is not sensitive enough. Antenna amplifiers must have extremely high specifications, in order not to influence the receiver specifications. RF Systems produces such an amplifier, covering long- medium- and shortwave: the WA - 50.
* SP - 1 splitter/combiner
Passive, for two receivers on one antenna or 2 antennas on one receiver. Frequency range : 50 kHz - 50 MHz. Impedance 50 Ohms, very low loss
* SP - 2 splitter
Housed in a metal cabinet, this passive splitter makes it not only possible to connect two receivers to one antenna, but is also equipped with a step attenuator (0 to - 40 dB) to prevent receiver overload. A built-in medium wave suppression filter can be switched into the antenna circuit. This makes it possible to listen with full sensitivity on long- and shortwave without interference from strong medium wave stations. A built-in antenna switch makes it possible to connect the receiver(s) to two different antennas with the flick of a switch. The attenuator, medium wave suppression filter and antenna switch make the SP - 2 also ideally suited for the use with just one receiver.
Frequency range 50 kHz - 50 MHz. Impedance 50 Ohms.
* SP - 3 splitter/combiner for scanners
Passive, for two receivers on one antenna or two antennas on one receiver. Frequency range: 10 MHz - 2500 MHz. Impedance 50 Ohms, ultra low loss, BNC connectors.
* DA - 4 active splitter/distribution amplifier
Up to 4 receivers without signal loss on one antenna. Housed in metal cabinet.
Frequency range 10 kHz - 50 MHz. Very high isolation between the receivers. Dynamic range > 125 dB, very high intercept points.
* DA - 8 active splitter/distribution amplifier
Up to 8 receivers without signal loss on one antenna. Housed in metal cabinet.
Frequency range 10 kHz - 50 MHz. Very high isolation between the receivers. Dynamic range > 125 dB, very high intercept points.
* WA - 50 antenna amplifier
Broadband amplifier for the 50 kHz - 50 MHz frequency range. 10 dB gain, 50 ohms in- and output impedance. Low noise, very high intercept points.
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