Constructions

Topband with its wavelenght 160m is not very easy band. Dimensons of antennas are extensive. For MW9W contest crew I have prepared simple but effective antenna for 160m – the Inverted L antenna. It’s based on the material DK5WL „Invisible“ DX Antenna for the Low Bands.

I bought two fibreglass poles with total height 12,5m and prove the antenna in the IARU HF Championship with impressive result. Try it too!

The Inverted L antenna is simple quaterwave antenna with a shape of inverted L letter. Most transmitted energy is vertically polarized. That’s an advantage for DX contacts.

Antenna azimuth indicator

Are you using a cheap antenna rotator like AR-300? I have three these rotators and on one I have found a difference between the real antenna azimuth and indication. After few hours was the difference 80 degrees. Rotator, especially rotator with a top bearing is constructed well and could be used also with a larger antenna as a HF monoband yagis for higher bands or smaller tribander.

I have developed simple antenna azimuth indicator – aziumth measurement. It’s a simple Wheatston’s bridge where is used a pot attached to the rotator tube as sensor. Voltmeter is showing directly azimuth in degrees from 0 to 360.

DK7ZB yagi

The reasons why are DK7ZB yagis popular are following reasons: very good performance and easy building. We are using DK7ZB yagis too. In recent years we have build: 2 x 3el. 2m 50 ohm crossed for SAT operation 5el. 2m 28ohm for portable use 7el. 2m 28 ohm two stacked antennas 8el. 2m 28 ohm 9el. 2m 28 ohm, two piecs 17el. 2m 28 ohm rope yagi 13el. 70cm 28 ohm, two pieces
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PTT footswitch

PTT footswitch is an addition that was developed especially for SSB contesting. Contesting does not allow to use a hand microphone – hands are used to control RIG, rotator, power amplifier, antenna switches and logging contacts. So we decide to use a headset with microphone with a PTT footswitch.

Commercial headsets for amateur radio are very expensive. So we choose cheaper headset for personal computer with an electret microphone and RX/TX switching is done by homemade PTT footswitch.

WI-FI antenna

WI-FI band (2.45 GHz) is not so far from 2.3 GHz what is a radioamateur band 13 cm. An idea of G6KSN was the base how to build own WI-FI antenna. I have compared three WI-FI antennas: original from AP, home made DL7KM (twin quad) and 10-element yagi loop. The last is the best. It's not a problem to copy signal from AP in distance 4.5 km!
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USB CAT cable for Yaesu FT-1000MP

The Yaesu FT-1000MP is a very popular transceiver for contesting. A very useful addition is a CAT system which allows to control the RIG from computer (tuning on the spots, bandmap, direct frequency entry in the log, etc). FT-1000MP has built-in a CAT interface.

Interface is using a RS-232 bus (COM serial). This bus is obsolete now, new computers and laptops does not have this one. If yes, we are also requiring it for PTT or rotator control. So we must use an USB to COM interface.

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