Those old gas discharge tubes are getting a bit long in tooth. They are almost impossible to find and if you do come across some, they'll cost you your first born. I have designed a pcb that uses common LED displays. Does the display in your SB-104 only work some of the time? Does your display have missing segments or burnt out tubes? Those gas discharge tubes are getting harder and harder to come by. Then you should consider using this LED display board. It fits onto the mounting studs of the original display. Common LED displays are use. the same wiring harness is used. Although the project is easy to build, all the parts mount on one double sided pcb, installing the new board is not for the faint of heart! A copy of the original SB-104 assembly manual will be needed. The board is a drop in replacement for the gas discharge tubes used in the original SB-104 (A). The new LED display does not require the +180 volts that the gas discharge tubes required, therefore you can disconnect the noisy RF dc to dc converter! I also added the option of adding a decimal point between the mhz and khz displays.

The universal keying module will work with just about any keyer and any radio. It’s simple to build and easy to hook up.


The universal keying module will key your old Heathkit DX-20 or your Drake 2NT that uses grid blocked keying.

You can configure the universal keying module to key either grid blocked or cathode keyed radio. Today, all radios key by pulling their key line to ground. This is the same as cathode keying.

The universal keyer can also key some HF amplifiers. Their key lines must be positive. This includes the Heathkit SB220 and most of the newer amplifiers. This module will NOT work with the SB200 or the Collins 30L1.


The kit consists of the PCB and all components. There is no case included with the kit. Generally, there is more than enough room to install the PCB inside a radio. If not, a small plastic box from Radio Shack will work just fine.

The Protector is a small circuit board that is installed between any 12-volt radio and a 12-volt power source. The power source can be anything from an AC line operated supply to a 12-volt battery at field day. It will protect the radio against over voltage and from reverse polarity. It will also provide a delayed start up, just in case you forgot to turn the radio off before connecting it to power.
Even though the Protector will protect any load connect to it against reverse polarity and over voltage conditions it will do so without blowing fuses. In either case, once the problem is fixed, the Protector will once again allow power to be sent to the load.
The Protector is easy to build and requires no adjustments or set up. By design, operation is totally automatic and requires no user inputs. It is completely transparent to the user.
If you know what end of the soldering iron gets hot, you should be able to assemble the Protector in less than an hour. All the parts mount on a single double-sided PC board about the size of a playing card.

The Micro M+ will handle up to 4 amps of current from your solar panel. There's a single LED that indicates the charging status of the battery you're charging.
The Micro M+ comes with everything you see here. There is no case included in the kit.
Assembly is quick and easy, but the pcb is small so the Micro M+ should not be your first kit you ever soldered together.
You will need a digital VOM and a adjustable power supply.