Fig. 1. ASPIS-450 schematic diagram
The ASPIS-450 receiver protection unit does not protect a receiver or the unit itself from a direct or indirect lightning strike and by no means I accept any liabiliy. The unit is equipped with a Plasma-gas discharge tube and 100V ESD protection devices, which is very good and welcome if your receiver doesn't have any, and grounding the screw provided on the box improves its ability to keep your receiver healthy inside a hostile environment. Adding surge protectors on the antenna line adds to safety. Because the reaction time of the unit is sub microsecond this design can offer best protection against distant strikes which otherwise would have caused damages. Older designs with lamps, bulbs and fuses are much slower to break so to actually protect. The front panel meter is a nice addition, if one day you see large readings, disconnect your antennae and don't operate. If your system is near to high power generators, other transmitters etc. yes, the unit can protect your receiver, again within limits. But high power interference and lightning strikes are totaly different matter and the reader should have been warned.
A completely built & tested Module is at EUR 129.00 without VAT 24% with EUR 15.99 shipping from Greece (EU).
The 24% VAT is only applicable to individual buyers from the EU countries.
The shipping is with Registered Mail with tracking info. It usually takes about 2-3 days for Europe and 8-10 days for USA/Canada.
10 KHZ - 450 MHZ
Very Low Loss Directional Coupler
RF Power meter based on fast AD8310 Log-amp
PIN diode for instant protection and receiver port grounding through a relay
It is based on the Analog Devices AD8310 fast log-amp and on a Mini-Circuits signal-tap (directional coupler)
Its major features and benefits include:
Antenna input port - Receiver output port impedance: 50 Ohms
Extremely low loss (0.12 dB at lower frequencies through VHF, 0.4 dB max at 450 MHZ)
Max input RF power level: 1 Watt CW or 12 W pulse
Supply current: 250 mA max at a supply voltage of 12-18 V
ESD supressors both at Antenna and Receiver Ports (100 V trip voltage)
Plasma Gas Discharge tube 70V at the Antenna input port
Directional Coupler from the Antenna input to the Receiver output offering galvanic isolation
True RF power meter with 90 dB dynamic range and super fast (20 ns) response
Front panel adjustable threshold (set-point) of the power level desired to enable receiver protection
12 W PIN diode across the Receiver port for immediate protection
Optional receiver port grounding through an RF Relay contact (remove jumper to disable this option)
Internal 10 MHZ test oscillator for system check
Event counter output (TTL) for system logging
Set and forget device. Protect your precious receiver from nearby static discharges, high-power narrow-band and wide-band sources, transmitters, generators etc. As soon as the antenna input power increases your receiver input will get grounded for as long the input level is above the setpoint.
ORDERING: NOW IN STOCK!
As it is now, the power meter is a wideband power meter, the displayed power level is of a signal that is >450 MHZ wide. This is how it's supposed to be, so the receiver can be a wideband one. But you can connect an external filter to get more accurate readings about a specific frequency range for example. Adding a 30 MHZ low-pass filter will make the meter respond only up to 30 MHZ. Or connecting the power meter to a receiver's filtered IF output will make a nice S-meter.
You can also use ASPIS-450 as a frequency trap. For example, you can place a band-pass filter centered on any frequency, prior to the unit. When a signal appears emitting on this frequency and its signal strength is above the setpoint, you can get a notification delayed only by the filter group delay and the total system's reaction time.
Copyright © Makis Katsouris, SV1AFN. All Rights Reserved.