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Thursday, July 26, 2007

Antenna Tuner / ATU

The progress of building this ATU seems to be slower. The ATU consist of an air core inductor and two variable capacitor. This ATU is enough for QRP up to 50/75W. Winding an air core inductor is not that difficult if you analyze the mechanical structure. I use the plexiglass as the support structure and a split pvc tube as a former. After finishing the winding, the split pvc is removed.
The variable air-gap capacitor is a 365pF x 2 and I have 2 of this capacitor and it is just enough to build 1 unit of ATU for myself. After completing the prototype, I simply build a temporary dipole antenna stretched across my apartment balcony. The dipole length is about 16ft one side. Tuning the antenna to give 1:1 swr at 5W on 6m & 10m is not a problem at all. However, I have yet to receive any transmission on 6m & 10m due to the condition of my current QTH. A vertical antenna could solve this problem but I dont want to risk my neighbours to the RF radiations. I will rebuild this ATU and housed it in a sealed metal enclosure to prevent any RF leakage. If you are interested to build this ATU, click here

2 comments:

Jurukaka said...

Woww....!! Last week u cerita tapi ini minggu terus jadi!! Bagus!!

tapi better kalau kurangkan 'talian penghantaran' kerana loss yang tinggi banyak terhasil di dalam ATU.

Last sekali pastikan kotak 'casing' jenis logam pengalir terbaik supaya inteference tidak menggangu penalaan :). Sediakan skru Ground bersama.

Good job!!

9W2DTR said...

Ha ha ha.... Thanks for the advice. Sebenarnya, memang betul apa yang an da kata. Saya memang berniat untuk memindahkan ATU ini kedalam bekas logam untuk mengurangkan segala gangguan yang mungkin akan terhasil.
Tentang'loss', betul. saya akan memendekkan wayar penyambung. Ini sebenarnya hanya untuk percubaan. Memandangkan ianya berhasil, pemindahan akan dijalankan dalam beberapa hari lagi.