Thursday, November 5, 2009

antenna astra @kaki biawak

lama juga tak menjenguk kedalam blog aku ni, maklum lah sibuk dengan tugasan saltmine.
namun dalam sibuk -sibuk aku ni sempat jugalah aku mencuba satu jenis antenna yang suatu masa dulu amat popular di kalangan rakan-rakan radio iaitu antenna astra ataupun kaki biawak.
setakat mana popularnya tu tak tau pulak sebab tak ditulis ratingnya berapa tapi memang berbaloi dan senang untuk di buat.

Antenna Astra
Plan Homebrew Antenna ASTRA 2 Meter VHF

gambar dan diagram ini saya dapat daripada salah seorang rakan ham kita iaitu 9w2wtf dan banyak info yang saya dapat dari dalam blog beliau.
untuk anda yang tercari-cari antenna apa yang ingin cuba di brew kan, cuba lah yang ini dulu sebab murah dan mudah ,. 73

Wednesday, January 28, 2009

power suply.

Here is a guide to modify your PC power supply unit to power up your mobile rig. If its done correctly you can have a cheap (regulated) VDC power supply solution for your mobile rig to operate at home.

Step I

First get a ATX PC power supply from the nearest computer store. Price is around RM30-70.

PSU Power Supply ATX

Make sure it could supply sufficient current. Look at the label. We need at least 10-17amp at 12V for a sufficient operation of mobile rig. Lower Ampere rating means that your mobile rig cant transmit with a typical HiGH setting (50w).

Step 2

Look for ATX power connector. It should look like this.

ATX Connector Ham RaDIO

Look for black and green wire at the ATX connector. The wire position is 4th from the top left side of the connector and 4th from the bottom right side from the connector as pictured above.

Black wire

Cut the black and green wire. Trim all the other wires as we wont need them.

Tie both Black and Green wire together.

PSU Green and Black Wire Ham radio

Connect both Green and Black wire to bypass the PC Power Supply unit. Insulate it with some tape. and switch on the power supply. If the fan is running, that means you’ve successfully completed this step!

Step 3.

Ham radio power connector

Turn off the power supply. Look for HDD, CDROM power connector, as pictured above.


Cut all wire from the connector.

Ham radio power supply howto

Separate 2 black wires and one yellow wire. Combine both black wires together.



Look for an extra mobile rig power connector, this can be obtained from electronic shops car accessories, or car battery shop.

Connect the yellow wire (+12 volt DC) to the positive terminal at the power connector as pictured above. Connect both black wires together and put it to the negative terminal as picture above too.

Step 4

Amateur radio cheap power supply
Cut all unnecessary wires, connector, and leave the power supply with just the rig power connector like this. It will look much more presentable and neatly prepared.

Mobile rig 13.8 VDC power supply

You can test the output voltage of this power supply by testing it with Voltmeter/Multimeter. Here you can see that the power supply output voltage is about 12V, which is suffiecient to power a mobile rig (13.8V +/- 15%).

Step 5

Finally, connect the power supply to your mobile rig to power it up. Enjoy your QSO!

FAQ: Nice, but my mobile rig require 13.8VDC to operate, this PSU only supplies 12V, it won’t work
Actually it can work. Mobile rigs requires 13.8 +/- 15% VDC to work (check your rig manual). and that gives a range about 11.7V - 15.8V of stable voltage potential. So a 12V power supply with sufficient current (15A and above) is definitely sufficient to power the mobile rigs.