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Call 0345 2300 599The KiwiSDR Protection Circuit V2 is designed to provide an additional level of protection for sensitive SDR receivers against potentially damaging RF and electrical events.
It was developed following a number of cases where KiwiSDR receivers had suffered serious damage as a result of:
- Nearby lightning activity
- Transmitting from an antenna positioned close to the KiwiSDR receiving antenna
- Accidentally transmitting directly into the KiwiSDR antenna input
Although designed with the KiwiSDR and KiwiSDR 2 in mind, the protection circuit can also be used with other receivers and SDRs.
Improved V2 Protection
The V2 circuit builds on the original protection unit, which provided effective protection against nearby lightning activity, static discharge and similar transient events.
The updated design adds a replaceable 100mA fast-blow fuse as an additional level of protection against higher RF power reaching the receiver input.
This helps improve protection in situations where RF is accidentally transmitted into the receiving system.
RF Protection
The V2 design combines multiple protection methods.
A 100mA fast-blow fuse is fitted in the RF path to help interrupt potentially damaging levels of RF power.
Signal diodes are also used to clamp the voltage coming from the RF transformer before it reaches the connected receiver or SDR.
During testing, the fuse operated at approximately:
- 1W RF: approximately 2 seconds
- 10W RF: approximately 1 second
- 100W RF: effectively instantaneous
These figures are intended as an indication of the protection circuit's behaviour during testing and should not be treated as guaranteed trip times under all conditions.
Replaceable Fuse
Each protection circuit is supplied with a spare 100mA 1808 fast-blow fuse.
If the fitted fuse operates, the cause should be investigated before replacing it and reconnecting the receiver.
A fuse can be checked using a multimeter on the resistance range. A good fuse will typically measure approximately 2 Ohms.
The fuse is replaceable, allowing the protection circuit to be returned to service without replacing the entire unit.
Grounding Requirements
Correct grounding is important for the protection circuit to operate as intended.
The back-to-back protection diodes rely on there being a suitable ground reference. If the RF input and ground rise together, as can happen with common-mode voltage, the diodes may not provide the expected protection.
This is particularly important when using antennas that are not naturally grounded, such as dipoles.
For a KiwiSDR 2, the enclosure is connected internally to the radio ground. A suitable ground wire can therefore be connected to one of the enclosure screw terminals.
For best protection, ensure that the receiver and associated antenna system are correctly grounded for the installation.
Suitable for More Than KiwiSDR
Although designed specifically around the KiwiSDR family, the protection circuit can be used with many other receivers and SDR systems where additional RF input protection is desirable.
It is particularly useful where receiving antennas are installed close to transmitting antennas, or where there is a risk of accidental RF being fed into a receiver input.
Key Features
- Improved V2 protection circuit
- Designed for KiwiSDR and KiwiSDR 2
- Suitable for many other receivers and SDRs
- Helps protect against nearby lightning and static
- Helps protect against RF from nearby transmitting antennas
- Additional protection against accidental transmission into the receiver input
- Replaceable 100mA fast-blow fuse
- Spare fuse supplied
- Back-to-back signal diode protection
- Designed for use with a properly grounded receiving system
- Ideal for SDR stations operating alongside transmitting equipment
Shipping:
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Returns:
If you have any equipment that needs to be returned to Martin Lynch & Sons, please fill out the form below:
Upon receipt of goods you have 14 days to return goods however the goods must be returned in original packaging and care must have been taken with the goods you wish to return. Under distance selling regulations you are not entitled to any refund on carriage charges or modification charges made at your request. Large items cannot be returned if they have been assembled, unless faulty.
Warranty Terms and Conditions
Outside of the 14 faulty return period, returned items cannot be accepted, unless covered by manufacturer's warranty. We will repair as much as possible on site however in exceptional circumstances products may have to be returned to the manufacturer of distributor.
For repairs/replacements under manufacturer’s warranty for any item please download a ML&S return form from the link above and return to ML&S with the faulty product.
International Warranty information
Warranty service for items we sell is available in the U.K. only, unless otherwise noted. It is your responsibility to pay freight for returned items to the U.K. and back to you for desired warranty coverage. All of our NEW products come with a minimum 12 month warranty, (Yaesu & Icom 24 months), with up to 90 days on second-hand equipment. Items returned for service must state "returned goods for repair" on the return air waybill or U.K. import customs duties apply and will be added to your invoice. For more info about returning items please contact our customer help desk, [email protected]