2016年6月15日 · It sounds like the radar scanner has a problem with a relative inexpensive part called the reed relay. The antenna switches it once for every rotation. Since it is constantly switching, older radar scanners tend to see them wear out.
A commercial data scanner using a bank of reed relays failed during thermal-vacuum testing of the SEASAT-A Synthetic Aperture Radar (SAR) Transmitter subassembly. Transmitter circuits requiring +5 volts were exposed to as high as 31 volts during each scan, resulting in catastrophic failure in the +5 volt circuits of the Transmitter.
2013年7月23日 · Check the reed relay switch up in the scanner. There is a small magnet on the bottom of the array that will pass over a little black looking thing once every rotation. This is the reed relay switch. With the system off, you can turn the array by hand and rotate it over the relay.
2006年2月11日 · Short answer is you are not likely to find any relay that can be tripped by the typical power output of a headphone jack (10 - 20 mW). You will likely need some sort of high output audio amplifier for that approach... Personally I would just design a simple circuit to trip the relay for you based on the audio level (i.e mosfet).
Electrical switching apparatus such as a scanner comprises a plurality of reed relays, each of which has an operating coil, and at least one reed contact unit which is mounted outside the...
2003年8月31日 · The relay test set employs three programmable RF scanners to handle eight relays at a time. The test set measures resistance by the two-wire rather than the (preferred) four-wire method mostly due to lack of reed switches.
Standex Electronics’ reed relays offer high isolation voltage between coil and contact up to 7000 VDC. These relays can switch up to 1500 volts and have a stand-off voltage of up to 5000 VDC across the open contacts. Bigger reed relays can have breakdown voltage ratings up to 15 kVDC or even up to 20 kVDC when
Reed switches or relays eventually fail in one of three ways. They do not open when they should (usually called “sticking”), they fail to close when they should (“missing”), or their static contact resistance gradually drifts up to an unacceptable level. At light loads, failure may not occur until several billion closure cycles have occurred.
Reed relays offer a compact and lightweight solution for switching of AC or DC signals. Contacts are hermetically sealed inside a glass envelope which protects them from corrosion. Compared with other mechanical-based relays, reed relays offer low power consumption, low contact capacitance and faster switching speeds. The new
circuits can work with isolation levels below 20 dB. Reed relays typically isolate signals down to -40 dB at lower frequencies (1 MHz to 200 MHz); and fall off to 20 dB in the 2 GHz to 3 GHz. The diagram below shows relay contacts where a pulse is incident )