Two antennas for improved reception on wideband scanners
The antenna, which has to pick-up the signals you want to hear, is equally important as the scanner it selves. Wideband scanners such as the AOR AR 3000/5000, Yupiteru MVT 7100 and similar receivers cover frequency ranges from 100 kHz up to 2000 MHz or more. They have however only one single antenna input connector for the whole frequency range. That's a problem if you want to listen on shortwave as well as VHF/UHF. Antennas, covering that enormous frequency range and giving good reception on all frequencies, simply don't exist. Shortwave and VHF/UHF antennas differ so much, that they can't be combined into one antenna. The solution is to use two antennas, one for shortwave, for instance a longwire with MLB, the other for VHF/UHF, such as a discone. Naturally it is possible to change plugs, but that's very unhandy. The solution is the DPX 30 duplexer/antenna combiner from RF Systems. It combines the signals of a shortwave antenna and a VHF/UHF antenna to the single antenna input of a wideband scanner without signal loss or switching over.
Two scanners on one antenna
Many scanner listeners have two scanners, but space for only one antenna. Connecting the antenna inputs together with the help of a T adaptor is asking for problems. Oscillator signals of one scanner will generate birdies on which the other scanner stops scanning. If the scanners are tuned to different frequency bands, the signals of one scanner can leak away into the other scanner with reduced sensitivity as result. The SP - 3 antenna splitter/combiner from RF Systems solves this problem. This device divides the signals of the antenna equally over the scanners, but the scanners don't "see" each other. This isolation prevents mutual influence of the scanners.
Two antennas on one scanner
In some cases it can be of advantage to use two antennas on one scanner. For instance an omni-directional antenna for local reception and a directional antenna for long distance reception, or a vertical polarised- and a horizontal polarised antenna. The SP - 3 splitter can also be used as combiner for two antennas on one scanner. The isolation prevents that the signals of one antenna are re-radiated by the other antenna, which will happen if the antennas are simply connected in parallel without the SP - 3.
Medium wave overload of hand-held scanners with an outdoor antenna
Most wide band hand-held scanners are made very sensitive, seen the bad efficiency of the whip or rubber duck antenna, especially for frequencies lower than 30 MHz. When an outdoor antenna, for instance a discone, is connected to such a scanner, often overload by strong mediumwave and shortwave stations occurs. Some stations (mostly mediumwave or shortwave stations) deliver with such an antenna more signal than the scanner can handle. The result is, that the strong station can be heard on every frequency or that the sensitivity of the scanner is reduced, even on other (VHF-UHF) bands. The only solution to this problem is to reduce the signal level of the strong stations on long, medium- and shortwave. This can be done on two ways. The DPX 30 duplexer has a VHF-UHF path which covers 30 MHz - 2000 MHz. With a DPX 30 between the antenna and the scanner, all stations on frequencies lower than 30 MHz are suppressed and cannot overload the receiver any longer. However, with a DPX 30 no reception on frequencies below 30 MHz is possible. If you are interested in shortwave reception with a wideband scanner, than there is another solution. The DX 500 antenna system comprises the DX 500/Attenuator. This passive device can also be used without the DX 500 antenna. Its is a so-called dual band device. It separates the incoming antenna signal into two bands: from 30 kHz to 30 MHz, and from 30 MHz to 2000 MHz. The VHF-UHF path passes un attenuated the device, but in the 30 kHz to 30 MHz path a continuously variable attenuator ( 0 - 40 dB) is incorporated. This offers the possibility to adjust the level of medium and shortwave stations in such a precise way, that they do not overload the scanner any longer, while the VHF-UHF stations are left un-attenuated. At the output of the DX 500/Attenuator both signals are combined again. The DX 500/Attenuator can be simply inserted between the antenna and the scanner.
* DPX - 30 duplexer/combiner
The DPX - 30 makes it possible to combine the signals of a shortwave antenna and a VHF/UHF antenna to the single antenna input of a wideband scanner. This device can also be used to protect sensitive scanners from shortwave overload when the scanner is connected to an outdoor antenna such as a discone.
* SP - 3 splitter/combiner
This device makes it possible to connect two receivers to one single antenna without mutual interaction. It allows also to connect two antennas to one scanner for improved reception possibilities.
* DX 500/Attenuator
Passive device with makes it possible to adjust the signal levels of stations in the 30 kHz - 30 MHz frequency range, without influencing the level of stations in the VHF-UHF (30 kHz - 2000 MHz)frequency bands. Impedance 50 Ohms.
The antenna, which has to pick-up the signals you want to hear, is equally important as the scanner it selves. Wideband scanners such as the AOR AR 3000/5000, Yupiteru MVT 7100 and similar receivers cover frequency ranges from 100 kHz up to 2000 MHz or more. They have however only one single antenna input connector for the whole frequency range. That's a problem if you want to listen on shortwave as well as VHF/UHF. Antennas, covering that enormous frequency range and giving good reception on all frequencies, simply don't exist. Shortwave and VHF/UHF antennas differ so much, that they can't be combined into one antenna. The solution is to use two antennas, one for shortwave, for instance a longwire with MLB, the other for VHF/UHF, such as a discone. Naturally it is possible to change plugs, but that's very unhandy. The solution is the DPX 30 duplexer/antenna combiner from RF Systems. It combines the signals of a shortwave antenna and a VHF/UHF antenna to the single antenna input of a wideband scanner without signal loss or switching over.
Two scanners on one antenna
Many scanner listeners have two scanners, but space for only one antenna. Connecting the antenna inputs together with the help of a T adaptor is asking for problems. Oscillator signals of one scanner will generate birdies on which the other scanner stops scanning. If the scanners are tuned to different frequency bands, the signals of one scanner can leak away into the other scanner with reduced sensitivity as result. The SP - 3 antenna splitter/combiner from RF Systems solves this problem. This device divides the signals of the antenna equally over the scanners, but the scanners don't "see" each other. This isolation prevents mutual influence of the scanners.
Two antennas on one scanner
In some cases it can be of advantage to use two antennas on one scanner. For instance an omni-directional antenna for local reception and a directional antenna for long distance reception, or a vertical polarised- and a horizontal polarised antenna. The SP - 3 splitter can also be used as combiner for two antennas on one scanner. The isolation prevents that the signals of one antenna are re-radiated by the other antenna, which will happen if the antennas are simply connected in parallel without the SP - 3.
Medium wave overload of hand-held scanners with an outdoor antenna
Most wide band hand-held scanners are made very sensitive, seen the bad efficiency of the whip or rubber duck antenna, especially for frequencies lower than 30 MHz. When an outdoor antenna, for instance a discone, is connected to such a scanner, often overload by strong mediumwave and shortwave stations occurs. Some stations (mostly mediumwave or shortwave stations) deliver with such an antenna more signal than the scanner can handle. The result is, that the strong station can be heard on every frequency or that the sensitivity of the scanner is reduced, even on other (VHF-UHF) bands. The only solution to this problem is to reduce the signal level of the strong stations on long, medium- and shortwave. This can be done on two ways. The DPX 30 duplexer has a VHF-UHF path which covers 30 MHz - 2000 MHz. With a DPX 30 between the antenna and the scanner, all stations on frequencies lower than 30 MHz are suppressed and cannot overload the receiver any longer. However, with a DPX 30 no reception on frequencies below 30 MHz is possible. If you are interested in shortwave reception with a wideband scanner, than there is another solution. The DX 500 antenna system comprises the DX 500/Attenuator. This passive device can also be used without the DX 500 antenna. Its is a so-called dual band device. It separates the incoming antenna signal into two bands: from 30 kHz to 30 MHz, and from 30 MHz to 2000 MHz. The VHF-UHF path passes un attenuated the device, but in the 30 kHz to 30 MHz path a continuously variable attenuator ( 0 - 40 dB) is incorporated. This offers the possibility to adjust the level of medium and shortwave stations in such a precise way, that they do not overload the scanner any longer, while the VHF-UHF stations are left un-attenuated. At the output of the DX 500/Attenuator both signals are combined again. The DX 500/Attenuator can be simply inserted between the antenna and the scanner.
* DPX - 30 duplexer/combiner
The DPX - 30 makes it possible to combine the signals of a shortwave antenna and a VHF/UHF antenna to the single antenna input of a wideband scanner. This device can also be used to protect sensitive scanners from shortwave overload when the scanner is connected to an outdoor antenna such as a discone.
* SP - 3 splitter/combiner
This device makes it possible to connect two receivers to one single antenna without mutual interaction. It allows also to connect two antennas to one scanner for improved reception possibilities.
* DX 500/Attenuator
Passive device with makes it possible to adjust the signal levels of stations in the 30 kHz - 30 MHz frequency range, without influencing the level of stations in the VHF-UHF (30 kHz - 2000 MHz)frequency bands. Impedance 50 Ohms.
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