Description
Update 16 August 2021 23:07
Lots of folk have read the Radcom article and have been wanting the board+parts. I have placed an order for more parts and these have been ordered as “back-orders” to be posted when the parts arrive next week.
These have now all been spoken for. I appreciate it is frustrating but this is just a hobbyist helping out others and I daren’t take more orders until I am on top of these latest backorders.
I estimate that no more orders can be placed until 20th August but will keep you updated. In the meantime I appreciate the many positive comments I have received. There is obviously an unmet need in the amateur radio world for high speed overvoltage protection.
PCB (Rev 1_1) and all the parts required to make a working BOB. You solder them yourself. It will trip if the power supply voltage is greater than 15/15.5/16V. By changing a few resistors you can change these trip settings – see the documentation
Short-circuit trip values are set by R1. In order to protect a 20-22 amp HF rig use 1.5 milliohms or for a VHF rig up to 70W use 3 milliohms. Some rigs (Yaesu FT991 for example) will draw 70 amps plus for a millisecond or so. You might want to experiment with a resistor of 0.5 milliohm or to dispense with overcurrent protection by using thick wire, or braid in place of a resistor. Regardless, you should always use ordinary fuses as recommended by the manufacturer.
There are no connectors included. They are relatively expensive and not everyone wants them. I do have some left from the original project too and you’ll find them listed further below but for many folk, wires can easily be soldered either to the large 3mm diameter through holes or the smaller 1.8mm diameter through holes.
The parts are delicate and I am selling parts “as is”, no warranties nor guarantees. I am not a retailer – just a hobbyist. These items have passed through my hands from RS Components or Mouser and they should be considered as used items although none have been anywhere near a soldering iron.
There is sufficient documentation on this site to build the board but there is no step by step guide. Apologies for all of these caveats but there is no official support to get it working although if you drop me a line I am always happy to help if I can. This is a hobby for me and is just an experiment in sharing my own projects with others. You are welcome to download the files and get the PCB made yourself – it is very easy to do these days. Just forward the zip file to a PCB fabricator of your choice like Eurocircuits. You could even sell them if you like !
Parts included
| C1 | 100u |
| C2,C3 | 100n |
| C4 | 1n |
| C5 | 0.22u |
| D1,D3 | Green LED |
| D2 | Red LED |
| Q1, Q2 | MOSFET |
| R1 | Option |
| R2, R9 | 1.2K |
| R3 | Option |
| R4 | Option |
| R5 | 100K |
| R6 | 24K 1% |
| R7 | 62K 1% |
| R8 | 22K |
| U1 | LTC4368 |
| PCB |
