Dover Amateur Radio Club

Construction Contest 2014

The Construction Contest 2014

On the 29th of October the 2014 Contruction Contest was held @ DARC. Many thanks to our guests John G3YCV and Don G4TKR for doing the judging.

Sadly there were only 3 entries, but 3 very good ones! - Peter G3MLO, Peter G0KOK and Pete M0PKH had Items to enter.

Starting with the results. Peter G3MLO Came at first place.

G3MLO's Entry - 2m 1kw Linear

John G3YCV Presents the Shield to the Winner Peter G3MLO, Well done Peter.

Peter constructed a 1kw 2m Linear amplifier. Full details here from his contruction notes.


Pete M0PKH's Entry - Shack in a Box

A very well made "shack in a box" - Pity no DSTAR Radio was added!

“Shack in a box” by M0PKH

A recent career change and following on from that, shack relocation led to some changes. The main purpose of the shack was now a study area. However, like many Amateurs’ I had accumulated many bits of kit. I had an Icom Pro 3 but also a KX3 spending most of its time packed away.

I decided to let the pro3 go but knew I would miss the panadaptor. Luckily, Elecraft were working on one for the KX3; so the decision and plan was formed. My next dilemma was could I really cope with just 10 watts when my antennas were not that good? I decided not and after seeking advice got my hands on the PA and filter units from a Yeasu FC-707.Being an older model it did not have top band but as I only occasionally use this band for the club net I decided that was a compromise I could live with.

The two antenna I currently have at my QTH are an end fed and a centre loaded vertical for 160M. I also have a small dipole for 40M that I may try in the loft. Although I do have 2 or 3 ATU’s I felt it was a waste to have them sat idle for most of the time so I decided to opt for some remote relay switching in the loft.

The speakers on the KX3 are quite small so I also thought it would be worth adding a stereo audio amplifier to the mix.

Other additions are QRP/QRO selection; this is achieved with a bypass relay in the antenna circuit. There is also a VSWR meter as there is already a bridge on the yeasu board that was utilised and an LED strip light to give local illumination.

Although there is now a 2M board available for the KX3 I decided to utilise a separate radio for this purpose.

I drew the panels up on CAD and laser cut/engraved them. The MDF panel is an early prototype.

P.Halloway - 28/10/2014


Homebrew Station - Peter G0KOK

My main project,
a complete 40 mtr station.

I found a tin that I liked measuring 90 X 90 X 40 mm, I then set myself a target that all the station units will fit in the same sized tin.

 Starting with the power supply and audio amplifier on the left, it has ten minh cells a speaker and audio amp' section.

 The transceiver started out as a small Hendricks qrp direct conversion kit, this unit gave me the most problems and has been extensively modified, I added a home brew PA board with filtering that produces seven Watts, a switching unit for t he PA and a second crystal so that I could be on or near the qrp frequency (7.030 ) and FISTS ( 7.028 ) by manual switch.

SWR/PWR bridge, a basic design with twin meters, no particular calibration marks just min' return and max smoke.

ATU/AMU again a standard design, two variable capacitors and a switched inductor with a built in dummy load.

Balun, standard 4:1 design.

Morse key, this unit required some time in my machine shop, the Iambic paddle was constructed from brass stock and stainless fittings, the finger pads were key ring fobs, it has fully adjustable contacts and tensioning.

In addition two other small entries.

1. Banks Morse key, constructed around a bottle opener, and machined parts.

2. Frequency counter and dummy load, made up from a Chinese counter and two 100 Ohm resistors, nothing special just a tool to check out my qrp analogue transceivers on the bench.

Peter G0KOK