Features

• Full 80m LSB coverage
• >5 watts output power
• Frequency display with 'huff and puff' circuit
• Modulation monitor
• Volt meter
• Reverse polarity protection

Specifications

Operating frequency - 3.5 - 3.8 MHz

RF Output - 6-7w

Sensitivity - MDS better than 1 uV

IF Frequency - 9.998 MHz

Audio Output - 0.5w

Current - Receive 120 mA, Transmit 1.2 amps

Supply Voltage - 10-16V

Microphone - Low cost PC electret type with added PTT

Loudpeaker - 8 Ohm

Notes

The supplied kit, comprising of the main PCB, the display, the componets and box was nicely sorted with sets of components neatly arranged in numbered bags to match assembly instructions. This made prepearing for construction very straight forward.

I completed the build over about 6 evenings in January/February 2009. I had no previous experience of building this kind of kit.

The instructions were very thorough and easy to follow. Soldering components was mostly straight forward, although I quickly found that my old iron was not getting hot enough.

Once I'd obtained a new soldering iron (with control to 400c) I had only two problems with the build itself:

(1) soldering the tiny wires from the transformers and inductors to the board was a struggle, as my eyesight isn't that good. Having failed to do it properly the first time, I removed a small piece of tracking de-soldering a transformer and a repair had to be made (by Steve G6ALU); and

(2) it was difficult to make a good job of cutting out the display window from the supplied box. Thankfully the overlay covers a multitude of sins and makes a very neat job of it.

On completion, G6ALU kindly gave the main PCB the once over for me and spotted at least one error - I had soldered a diode the wrong way round. He also repaired he tracking I had damaged during de-soldering and did the final tuning for me.

It was then a case of assembling the display (fairly easy), boxing up, making a PTT for the PC-type mic I had purchased from Maplin for £3.99, hooking up an antenna (my G5RV) and switching on...

On The Air

On switch on I was surprised by just how good the receiver is, given its simplicity. It was immediately pulling in the DX quite happily and there was not a marked difference between what I could hear on the MKARS80 and what I could hear on my main station rig - a Kenwood TS850S.

Two limitations quickly become apparent though - the selectivity is not great and the lack of AGC means you do have to adjust the RF gain frequently to avoid overload. Both these issues are to be expected and entirely fair enough for a transceiver costing £48 (price updated)!

Stability is surprisingly good. Steve has modified his original design and my '80 doesn't seem to suffer from the drift that earlier radios did.

On TX, the '80 is also surprisingly good. I worked into Europe straight away and was receiving 5/7 reports with good audio.

Overall, I'd strongly recommend the MKARS80. It's a great little radio and you do get a real buzz from working stations on a radio you've put together yourself. I have hardly had the Kenwood on since!