Wednesday, November 22, 2006

Friday, November 17, 2006

IC-V82 / IC-U82 VHF and UHF Transceivers

Optional digital unit, UT-118The optional UT-118 provides D-STAR format digital voice and slow data communiation. The UT-118 includes the following digital features.
Callsign callingIn the digital mode, your callsign and the receiving callsign (or CQ message) are included in each transmission. The callsign squelch allows you to choose an incoming call selected by the callsign. Also, received callsigns are automatically stored in the memory.
Position exchange with external GPS receiverWhen connected to an external GPS receiver*, position information can be exchanged with other stations. When the receiving side is connected to a PC**, position monitoring is possible.* NMEA 0183 output and RS-232C interface are required.** Position mapping software required (Not supplied by Icom ).
And more digital features20-character short data message
Digital code squelch
EMR communication
Digital pocket beep
Stand-by beep
7W powerful output powerA powerful 7W* output power provides superior transmit power. All this power is available with the supplied battery pack. Reduced power settings also allow you to adapt to the communication conditions and provide longer operating time.* 5W for UHF.
200 memory channels and 10 memory banksUp to 200 regular memory channels can be stored with a 6-character channel name, tone and duplex settings. The memory channels can be tagged with A-J bank name and allows you easy channel management. In addition, use Icom’s exclusive DMS (Dynamic Memory Scan) system to scan selected memory banks by simply adding and deleting blank links.
Built-in CTCSS/DTCSBuilt-in CTCSS/DTCS tone codes provide quiet stand-by and allow you to access a closed repeater. The pocket beep alerts you when a matched tone frequency is received. The tone scan detects the tone frequency used in the receiving frequency.
Other features
NOAA weather channel receive (IC-82 USA version only)
Automatic repeater function (USA version only)
Reversible control knob and up/down buttons assignment
Durable construction and simple operation
16 DTMF dial memory
PC cloning capability

IC-2720H - 2 Meter / 70 cm Dual Bander

New, advanced 2 M/70 cm mobile dual bander. Click on the small image to get a large picture of the IC-2720H.
Dimensions (Control Head): 5.5 (W), 2 (H), 1.1 (D) in, 5.29 oz
Dimensions (Main Unit): 5.5 (W), 1.6 (H), 7.375 (D), 3.08 lb
50 Watts (2M), 35 Watts (70 cm), 15 W, 5 W selectable
Rx: 118 - 550 MHz (left side), 118 - 174, 375 - 550, 810 - 999 (cellular blocked) MHz (right side, guaranteed on ham bands only)
Download the IC-2720H PDF brochure.
Display Features
Wide viewing angle for mobile flexibility
User-adjustable brightness controls
User-selectable amber or green colored display
Separate Control Head
Connection cable included
2 Microphone jacks - one on control head, one on main unit
Control head mounting bracket included
Independent Tuning Knobs
Tuning, AF, squelch and 4 function switches per band
Large controls for easier operation
V/V, U/U, V/U, U/V (Work dual or cross band)
Other Great Features
1200/9600 bps 6-pin Packet Terminal
212 Memory Channels which includes 2 Call Channels and 10 Scan Edges
Icom's Dynamic Memory Scan (DMS)
Organize your most often used frequencies into any of the IC-2720H's 10 memory banks
Plan trips by pre-loading frequencies into banks. Change banks as you travel along.
An Icom Exclusive
Extra Wideband Reception (see above) Includes Weather and Air Bands
CTCSS and DTCS Encode/Decode Operation with Tone Scan and Pocket Beep
50 CTCSS, 104 x 2 DTCS
Gets you on the Repeater, Fast
DTMF Encode
Full Function, Backlit Mic with Icom's Exclusive Hot Keys (Great for your most used settings)
10dB Attenuator
Auto Repeater (USA only)
Weather Alert (USA only)
Large Cooling Fan with Adjustable Speed and Flow-Thru Chassis Ventilation
Die-Cast Aluminum Chassis
PC Programmable Optional. CS-2720H software and OPC-478 cable required
More detailed IC-2720H specifications and options. (PDF)


IC-V8000 2M Mobile, power when you need it!
75 Watts of output power! With Icom's new IC-V8000 you can reach that mountain top, punch through that urban canyon - talk and be heard further! The combination of the V8000's one-piece, die-cast aluminum chassis and 75W of transmit power gives you the most powerful 2M mobile in its class. but that's not all. We've added features like: Weather alert and Weather Channel Scan (first time in amateur radio); 207 Alphanumeric Memory Channels; Remote Control Mic; Icom's exclusive DMS Scan System (see below); and much more. Pick up a 'V8000 and let your signal be heard! Coming soon to your authorized Icom dealer.
Download the IC-V8000 PDF brochure.
IC-V8000 Features:
75 Watts output power
RX: 136 - 174 MHz
Wide/narrow operation
Front firing speaker
Cooling fan
Dual color display
Auto repeater offset
CTCSS Encode
CTCSS Decode
CTCSS Tone scan
DCS Encode
DCS Decode
DCS Code scan
DTMF Encode
DTMF Decode (optional)
DTMF Code squelch
Dynamic Memory Scan
Weather channels
Weather alert
Weather scan
207 Memory channels (3 scan edges)
Call channel
6 Character alphanumeric display
PC programmable
Radio - radio cloning
Programmable keys
RF Attenuator
Channelized operation
Alpha only operation

YAESU - VX 177 (NEW)

The VX-177 is an ultra-rugged 5-Watt 430 MHz hand-held ideal for use in the most demanding applications. Featuring big receiver audio (almost 3/4 of a Watt!) and long battery life, the VX-177 is protected against water ingress to IPX7 specifications (immersion in 1 meter of water for up to 30 minutes).
The VX-177 utilizes a 16-key pad for frequency and DTMF entry, as well as a wide variety of command functions.
200 Memory Channels
The VX-177 includes provision for storage of up to 200 memories, which may be allocated into as many as ten Memory Banks. Alpha/Numeric Labeling (up to six characters) of memories is also provided.
Wide Receiver Coverage
The VX-177 covers 420-470 MHz (U.S. version), so you can monitor commercial and government transmissions adjacent to the Amateur band.
Long Battery Life
The supplied FNB-83 Ni-MH Battery has a capacity of 1400 mAh for hours of operation after other radios have shut down with dead batteries.
Big Receiver Audio Output
The oversized internal speaker produces 700 mW of crisp, clean audio power, allowing you to hear important incoming transmissions even in noisy public service or emergency operations. CTCSS and DCS Included
The VX-177 includes full-featured CTCSS and DCS (Digital Code Squelch) tone control systems, for easy repeater access and/or silent monitoring of busy channels. "Split Tone" mode allows you to encode CTCSS and decode DCS, or vice-versa. And a "Reverse Tone" mode may also be engaged, to silence your radio's receiver when a matching CTCSS tone is received (to avoid the annoyance caused by interference from a distant repeater during times of enhanced propagation).
And much, much more. . .
•Huge LCD Display with Yaesu's exclusive Omni-Glow™ illumination •RF Squelch •Direct Keypad Frequency Entry •Security Password •Transmit Time-Out Timer (TOT) Automatic Power Off (APO) Automatic Repeater Shift (ARS) •ARTS™ (Auto-Range Transponder System) •Emergency Automatic ID (EAI) "Man Down" feature for Search-and-Rescue work Smart Search™ •Dual Watch


Unmatched Weatherproofing
The VX-7R case, keypad, speaker, and connectorts are carefully sealed to protect the internal circuitry against water damage. And the optional CMP460A Speaker/Microphone, like the transceiver itself, is rated for 30 minutes of submersion at a depth of up to three feet. The VX-7R is available in both Silver (VX-7R) and Black (VX-7RB) versions.

50/144/430 MHz: 5 Watts of Power
Utilizing a reliable FET power amplifier circuit, the VX-7R provides a full 5 Watts of power output on the 50, 144, and 430 MHz Amateur bands, with bonus coverage of the 222 MHz band at 300 mW (USA version only). And for 6-meter AM enthusiasts, you also get 1 Watt of carrier power on the 50 MHz band. Four power levels may be selected, each offering its own degree of battery conservation.

Dual Receive
The VX-7R is capable of four modes of Dual Receive, including simultaneous reception of (1) two VHF frequencies; (2) two UHF frequencies; one VHF and one UHF frequency; or one "general coverage" frequency and one "Ham" frequency. And you can set up the VX-7R to reduce the audio level on the "Sub" band, if you like, when a call is received on the "Main" band.

The Most Memories Ever
Sporting the most memory capability of any Amateur transceiver, the VX-7R includes over 900 memory channels, yet access is simple and intuitive, thanks to the 8-character labeling capability. These memories include 450 "regular" memories, 10 "One-Touch" memories, 40 programmable band-edge-limit memories 12 "Home" channels, 10 Weather Band memories, 89 Shortwave Broadcast preset memories, 280 Marine channels, and 10 "Hyper" memories that store complete transceiver configuration data.

The Most Dazzling Display Ever
No Amateur transceiver has a display that even compares to the VX-7R's 132 x 64 dot matrix disaply. Providing clear, easy-to-read indication of both the Main and Sub band frequencies, operating mode, and S-meters for both bands, the display includes an unparalleled array of graphical and pictorial tools that make operation a breeze.


The control head is detached and comes with remote cable for easy installation. The TM-V708A is a true dual-band operation radio so VHF+VHF/VHF+UHF/UHF+UHF operation is possible.
144/440 MHz TX operation
118-1.3 GHz receive with cellular + blocked
200 memory channels (not PC programmable)
10 memory scan bands possible
Visual band scope for scanning activity
Built-in CTCSS
Built-in digital coded squelch (NEW)
Remote control and cross-band repeater operation
Mars modifiable with permit
NEW backlite alphanumeric microphone for message input

Kenwood - TH-F6A (PORTABLE)

Finally, the Amateur Handheld that everyone has been waiting for, the New Kenwood TH-F6A. The TH-F6A is a 144/220/440 MHz transceiver/receiver with dual-channel RX capability in a compact and powerful design. The first Tri-Band HT with 3 bands you can operate EVERY DAY! The TH-F6A boasts a list of unique features the competition is still scratching their heads over.

144/220/440 MHz with 5 WATTS on all 3 bands
8 Character Alphanumeric Display
Up to 8 groups of 50 channels per memory bank
Famous Loud and Clear Kenwood Audio
Dual Channel Simultaneous Receive even on the same band
Easy access Single Knob Encoder/volume control
7.4 Volt 1550 mAh Lithium Ion battery (largest & most power in the industry)
4 Selectable Transmit Power Levels
Backlit “laser-cut” keypad for durability
MIL-STD 810 for vibration, shock and light rain
Built-in CTCSS Encode/Decode / DCS Digital Coded Squelch
10 DTMF Auto-patch memories
1200/9600 bps TNC ready (no adapter required)
Single High Performance Antenna (no switching required)
AM Aircraft Receive
TOT Time Out Timer
Weight with PB-42L Battery 8.8 oz.
First Ever Compact Amateur HT with Built-in VOX
435 PC Programmable Memories (over twice the competition)
3 Call Channels plus 20 for programmable scan
Special (10) Channel Weather station mode
Best HT ever for Satellite operation (including AO-27)
FM/FM – W/FM – N/AM + USB & LSB / CW
0.01~ 1300 MHz RX (widest transceiver in the industry)
Built-in battery charging system during DC operation
Battery Voltage Level Indicator
LARGE FONT mode for easy reading
Multi-Scroll Key for easy menu access
1750 Hz Tone Burst
Visual Scan to monitor adjacent channel activity
Automatic Simplex Checker
Built-in Ferrite Bar antenna for AM receive (0.1 ~ 7 MHz)
Wireless Remote Control
APO Auto Power Off
Optional BT-13 Alkaline Battery Case for Emergency use
Dimensions (W 2 5/26) x (H 3 7/16) x (D 1 3/16) inches

Tuesday, November 14, 2006


Apakah itu Radio Amatur?
Sepuluh Perkara yang anda perlu tahu berkenaan Radio Amatur

(dipetik dari risalah MCMC)
Radio Amatur atapun juga dikenali sebagai “Ham Radio” ialah hobi berkenaan membina, menguji-kaji dan berkomunikasi melalui radio.Pengguna-pengguna Radio Amatur ini saling berhubung dengan rakan-rakan mereka seluruh dunia melalui beberapa set-set frekuensi radio yang telah ditetapkan.

Bilakah Radio Amatur bermula?
Sejarah Radio Amatur ini telah bermula semenjak perhubungan radio digunakan. Pada tahun 1912, Kongress Amerika Syarikat telah meluluskan undang-undang pertama bagi mengawal selia pemancaran radio di Amerika Syarikat. Bermula 1914, pengguna Radio Amatur telah mula berkomunikasi dan mengadakan satu system penghantaran mesej di antara mereka. Di Malaysia, radio amatur merupakan titik bermulanya perkhidmatan radio komersil.

Apakah yang boleh saya lakukan dengan Radio Amatur?
Tidak seperti teknologi perhubungan lain, Radio Amatur membolehkan anda berhubung dari mana-mana tempat, pada setiap masa! Pada waktu-waktu bencana, Radio Amatur amat berguna, terutamanya kepada agensi-agensi penyelamat. Pada ketika lain, anda juga kadang kala boleh bercakap dengan para angkasawan atau membalikkan isyarat dari bulan! Anda juga boleh menghantar fail ataupun gambar secara digital. Adakah hobi lain yang menyediakan sebegitu ciri sepertinya?

Saya sentiasa sibuk. Adakah saya masih boleh menikmati hobi ini?
Sudah tentu! Hobi ini tidak terikat kepada sesuatu masa, tempat dan pendapatan seseorang. Memandangkan ianya mudah dikendalikan, ramai yang sentiasa sibuk mendapati ianya seronok digunakan dan mengurangkan tekanan selepas seharian bekerja. Anda dan juga keluarga anda juga boleh menikmati dan mempelajari hobi ini.

Apakah perbelanjaan yang diperlukan bagi hobi ini?
Sebuah radio bersaiz telapak tangan yang baru mungkin sama harganya dengan satu TV 19 inci yang berkos rendah. Radio yang lebih besar adalah sama kosnya dengan satu komputer.Selain dari itu, bahan-bahan pembelajaran berkenaan Radio Amatur adalah berpatutan dan yuran peperiksaan bagi mendapatkan Sijil Perakuan juga adalah rendah.Secara alternatif, sekiranya anda cenderung untuk menguji-kaji, seperti kebanyakaan pengguna Radio Amatur atau “Ham Radio”, anda boleh membuat unit “Ham Radio” anda sendiri.

Siapa yang boleh membantu saya?
Kelab-kelab Radio Amatur terdapat di seluruh Malaysia dan bersedia untuk membantu anda. Ada di antara kelab-kelab tersebut mempunyai halaman web yang mengandungi maklumat mengenai hobi tersebut.

Bagaimana saya boleh menjadi seorang operator Radio Amatur?
Amatur. Bagi mendapatkan Sijil Perakuan, anda haruslah warganegara Malaysia berusia 14 tahun ke atas dan lulus ujian-ujian berikut:
* Ujian Teori Radio dan Kefahaman Peraturan Radio bagi Sijil Perakuan Kelas B; atau
* Ujian Kod Morse dan ujian-ujian teori dan radio di atas bagi Sijil Perakuan Kelas A.

Siapakah yang mengeluarkan Sijil Perakuan itu?
Sijil Perakuan tersebut dikeluarkan oleh Suruhanjaya Komunikasi dan Multimedia Malaysia kepada mereka-mereka yang telah lulus ujian yang diadakan.

Adakah saya perlu membayar yuran?
Ya, Sijil Perakuan tersebut haruslah diperbaharui setiap tahun. Yuran tahunan bagi Sijil Perakuan Kelas A adalah sebanyak RM36 dan bagi Sijil Perakuan Kelas B, yurannya adalah RM24 setahun.

Apakah yang boleh saya pelajari sebagai permulaan?
Anda boleh memulakan pelajaran anda dengan mempelajari fonetiks abjad yang digunakan oleh pengguna-pengguna Radio Amatur di seluruh dunia!

Kelemahan komunikasi pengurusan bencana


Sejak kebelakangan ini, kejadian nahas bencana banyak berlaku termasuk gempa bumi, tsunami, banjir besar, runtuhan bangunan, nahas kapal terbang serta helikopter.Anggota-anggota penyelamat yang ditugaskan untuk kerja-kerja mencari dan menyelamat kita memang terlatih dalam mengendalikan tugas berat itu namun disebabkan tidak ada koordinasi antara anggota-anggota penyelamat, ia sedikit sebanyak menghalang mereka melakukan tugas yang terbaik.Persatuan Perkhidmatan Kecemasan Radio Amatur Malaysia (MARES) yang kerap kali terlibat dengan kerja-kerja mencari dan menyelamat bersama-sama polis, pasukan Bomba dan Penyelamat, JPA3 dan Tentera Udara Diraja Malaysia (TUDM) sering mendengar keluhan di antara pasukan penyelamat itu.Kita mempunyai Unit Pengurusan Krisis dan Bencana, Bahagian Keselamatan Negara selain Jawatankuasa Pengurusan dan Bantuan Bencana di peringkat daerah, negeri dan pusat, namun bilakah mereka yang diamanahkan ini akan duduk berbincang?Adakah mereka hanya perlu duduk bersama setahun sekali atau hanya berjumpa apabila berlaku bencana?Apakah fungsi jawatankuasa ini? Adakah ia sekadar memenuhi garis panduan Jabatan Perdana Menteri (JPM) sahaja dan hanya inginkan pegawai yang mewakili agensi tertentu bercakap di meja rundingan termasuk menyediakan kertas kerja namun tidak ada pelaksanaan kerana tiada peruntukan kewangan?Di sini penulis ingin sertakan satu senario menarik untuk tatapan kita bersama. Persoalannya ialah sejak 15 tahun penulis menetap di sebuah bandar yang mempunyai beberapa pangsapuri, tidak pernah pun melihat atau mendengar Pelan Tindakan Kecemasan (ERP) atau Pelan Pemindahan (Evacuation Plan) di penempatan berkenaan.Bayangkan jika berlaku kebakaran atau gempa bumi, apakah yang akan dilakukan oleh penghuninya? Yang lebih memburukkan keadaan, sehingga kini tiada sistem pencegah kebakaran di kawasan penempatan berkenaan dan ini menimbulkan satu pertanyaan bagaimana pangsapuri itu mendapat sijil layak menduduki (CF).Apa yang kita lakukan sekarang lebih bersifat ad hoc dan bencana demi bencana berlaku namun kehangatannya hanya seketika sahaja.Kejadian Helikopter Hornbill Skyways - Bell 206 yang terhempas di kaki Gunung Murud, Ba'kelalan, Sarawak pada 12 Julai 2004 memakan masa 16 hari untuk dicari dan ini tidak dapat diterima oleh ahli keluarga mangsa serta masyarakat umum.Pada hari kejadian sehingga helikopter berkenaan dijumpai setiap hari media tempatan menyiarkan berita mengenainya termasuk siaran pendapat daripada beberapa individu mahir dan pakar mengenai perkara itu.Namun apabila ia sudah berakhir, tidak ada mana-mana pihak tampil ke hadapan melakukan langkah-langkah tertentu untuk memperbaiki cara dan tindakan menyelamat bagi membendung perkara berkenaan daripada berulang.Apa yang dikesali ialah kawasan tersebut merupakan kawasan sering terjadi nahas namun tidak ada sebarang `tindakan pembetulan' dibuat.Mesyuarat post-mortem nahas pesawat Piper 28 di Genting Bidai, Pahang tahun lepas turut menimbulkan persoalan masalah koordinasi antara pasukan penyelamat termasuklah masalah integrasi sistem komunikasi yang tidak sepatutnya berlaku pada zaman sekarang.Kita sering memberikan keutamaan kepada pasukan Bomba dan Penyelamat, JPA3, polis, Unit Udara PDRM, Unit Udara Bomba dan TUDM sebagai anggota agensi penyelamat.Akan tetapi kita sebenarnya tidak harus melupakan dan mendapatkan perkhidmatan daripada orang yang lebih arif mengenai kawasan berkenaan.Ini termasuk juruukur bahagian pemetaan, kumpulan pendaki gunung, pemburu, Orang Asli dan badan-badan NGO yang lain termasuklah ahli kelab pacuan empat roda (4x4) dan kelab radio amatur.Sebagai contoh, jika ada pesawat terhempas di kawasan hutan, khidmat kumpulan ini diperlukan kerana ada di antara mereka lebih arif kawasan tersebut dan tahu mengenai selok-belok kawasan tersebut.BantuanNegara maju contohnya Amerika Syarikat, Perancis dan United Kingdom sering menggunakan khidmat kumpulan ini, manakala agensi kerajaan dan swasta pula menyediakan bantuan kewangan kepada NGO.Namun amat malang ia tidak berlaku di negara kita.Jawatankuasa di peringkat nasional harus mengemas kini garis panduan pengurusan bencana contohnya Arahan Majlis Keselamatan Negara No. 20 (MKN 20) yang dikeluarkan oleh Jabatan Perdana Menteri (JPM) yang diwujudkan selepas tragedi Highland Tower pada 11 Disember 1993.Semenjak dari tahun 60-an sehinggalah sekarang, tidak ada perubahan dan apa yang kita nampak hanyalah kenderaan dan perkakasan mencari dan menyelamat, bot-bot, pam-pam air, ambulans yang baru.Apa yang dikesalkan sistem komunikasi sesetengah agensi penyelamat amat menyedihkan dan tidak mencapai tahap kemodenan yang ada sekarang.Turut dikenal pasti permohonan menaik taraf peralatan seperti pengesan kehidupan (life detector) dan alat komunikasi terkini amat sukar dan sering diklasifikasikan sebagai tidak penting.Malah ada satu agensi penyelamat negara, lengkap dengan segala peralatan baru termasuk kenderaan 4x4, komputer pejabat, ambulans, bas untuk anggota termasuklah sebuah kenderaan Proton Perdana V6 baru.Namun apabila memasuki bilik gerakan, hanya terdapat empat buah gagang telefon yang biasa digunakan untuk menerima panggilan kecemasan, sebuah alat perhubungan frekuensi sangat tinggi (VHF) dan sebuah buku catatan penerimaan panggilan kecemasan.Cuba bayangkan, jika berlaku sesuatu bencana yang besar sudah pasti bilik gerakan ini dihujani pelbagai panggilan yang tidak henti-henti daripada orang ramai.Jika mereka masih meneruskan dengan peralatan asas ini termasuk operator yang kurang berpengalaman, pastinya proses menerima aduan, memberi arahan dan melaksanakan arahan menjadi kurang efisien. Seterusnya, ia pasti akan melambatkan proses menyelamat.Semua ini berlaku di ibu negara dan ini membayangkan apa yang ada di lain-lain negeri. Dalam gerakan mencari dan menyelamat, salah satu alat yang paling penting ialah peralatan komunikasi.Namun perkara yang penting itu jarang diambil tahu dengan terperinci oleh pihak tertentu.-
ABDUL AZIZ MOHD. NOR ialah Presiden Persatuan Perkhidmatan Kecemasan Radio Amatur Malaysia (MARES).

Peranan radio amatur membantu erat hubungan

RADIO amatur bukan sekadar alat komunikasi sesama ahli atau denganpengguna lain, tetapi turut membantu ketika kecemasan seperti tanahruntuh, sesat di dalam hutan, banjir kilat atau nahas di darat, udaramahu pun air, apabila komunikasi sedia ada tidak dapat digunakan.Jika sebelum ini peralatan komunikasi seperti telefon bimbit digunakanuntuk berhubung, tetapi 'ham radio' memudahkan proses itu, khususnya dikawasan yang tiada talian kerana ia boleh berfungsi melalui tenaga bateriatau generator.Memang ada kod panggilan yang sukar difahami seperti"MEMANGGIL...9W2DZU (diulang dua kal)i atau 9W2DZU going QRT, 73...over". Barisan ayat disulami figura seperti itu kedengaran seperti sistemkomunikasi yang lazim bagi pihak berkuasa, polis atau tentera.Ia memang tidak akan difahami umum, kecuali mereka yang biasa denganpengendalian sistem komunikasi radio. Diterjemahkan, panggilan itu tadibermaksud - keluar dari jaluran atau frekuensi -. Ia kod panggilan atau'callsign' yang mula dituturkan oleh pengguna radio amatur atau lebihdikenali sebagai 'ham radio' untuk berhubung dengan orang lain.Sebenarnya, kod panggilan yang digunakan oleh pengguna radio amaturmembawa maksud pengenalan diri seseorang apabila pengguna berkenaan inginmemasuki talian atau berkomunikasi dengan orang lain.Seorang kontraktor dari Seremban, Hamid Abdullah, 44, yang sudah tigatahun terbabit dalam dunia radio amatur, berkata sistem perhubungan itubermula dengan penggunaan sistem itu oleh tentera British."Ketika berperang, tentera British berhubung melalui cara ini untukurusan menyampaikan bantuan kepada mangsa peperangan atau menyalurkanmaklumat kepada pihak atasan."Sejak itu, penggunaan sistem berkenaan berterusan di negara ini dankini semakin meluas untuk berhubung ketika mengendalikan sesuatu programatau aktiviti," katanya.Katanya, sistem seperti itu juga digunakan dalam sukan lasak pacuanempat roda, aktiviti yang kini mula mendapat perhatian pelbagai syarikatdan persatuan sukan di negara ini."Bagaimanapun, penggunaan radio amatur di negara ini terikat denganpelbagai syarat dan etika," katanya, menambah pengguna sistem itu harusmenduduki peperiksaan Suruhanjaya Komunikasi dan Multimedia Malaysia(SKMM) terlebih dulu."Hanya jika lulus peperiksaan berkenaan, barulah pemohon layak menerimalesen menggunakan radio amatur dengan jumlah bayaran dikenakan mengikutkelas sistem yang dipohon," katanya.Kelas A dikenakan bayaran RM36 setahun manakala kelas B dikenakanbayaran RM24 setahun, selain RM60 sebagai yuran pendaftaran.Hamid menganggap pembabitannya dalam bidang itu lebih menjurus sebagaihobi dalam menjalin hubungan dengan pelbagai peringkat masyarakat dalamdan luar negara."Selain bertanya khabar, sistem perhubungan ini turut digunakan apabilakami terbabit dalam pelbagai aktiviti sukan lasak, program berkaitan alamsekitar serta program kemasyarakatan."Penggunaan radio amatur dapat memudahkan tugas jika menghadapisebarang masalah, terutama apabila berada jauh di pedalaman atau dalamhutan," katanya.Beliau yang juga Pengarah Urusan Nine Adventure, syarikat pengurusanaktiviti sukan lasak, termasuk pacuan empat roda di Negeri Sembilan,berkata radio amatur memang memberikan banyak kelebihan kepadapenggunanya.Rakannya, Mazlan Shamsuddin, 48, yang mula berjinak dengan hobi itu,berkata sistem perhubungan seperti itu menyeronokkan kerana dapatberhubung dengan ramai kenalan tanpa perlu mengeluarkan belanja.Baru-baru ini, 300 pengguna radio amatur seluruh negara berhimpun padamajlis anjuran Rakan Radio Amatur Kuala Pilah di Perkampungan BudayaTerachi, Negeri Sembilan untuk bertanya khabar dan membincangkan aktivititahun ini."Kami perlu juga berjumpa dan bertentang mata walaupun dapat berbualmelalui radio amatur yang ada batasannya. Menjadi kesalahan dan bolehdikenakan tindakan jika berbual mengenai isu sensitif."Pengguna radio amatur tidak boleh membincangkan isu agama, politikatau peribadi yang menjejaskan imej seseorang secara terbuka melaluisistem ini," katanya.Seorang lagi ahli, Zulkifli Sulaiman, 43, berkata kemahiran menggunakanradio amatur memberikan banyak manfaat kerana ia juga dapat disalurkanuntuk membantu pihak yang memerlukan."Sebelum ini, sistem perhubungan itu digunakan ketika kami dimintamemberi bantuan kecemasan menyelamatkan kumpulan remaja yang sesat dihutan Gunung Angsi, Kuala Pilah," katanya

Saturday, November 11, 2006

Antena Know How

Since the late 1970's when I got interested in HF mobile operation, I experimented with a variety of antennas to find the best practical design installations. You see all antennas are limited by their aperture size. The larger the aperture size, relative to wavelength of operation, the greater antennas gain. There are however constraints upon this; you can't simply make big antennas and expect them to function. You can and should control impedance matching and antenna efficiency. Antenna efficiency is improved by bigger size conductors. This is to say; larger, fatter, conductors which have less resistive losses due to their large surface area, and consequently higher antenna Q. Smaller antennas have less aperture gain, on the HF bands typically negative gain, and also less efficiency because they have greater resistive losses.
Since we can only have relatively small antennas on a vehicle, we have to concede that all our HF mobile antennas will have negative gain, which means less than unity gain. Even the body of the vehicle itself, which is the antenna counterpoise, is usually only a very small fraction of the HF wavelength in use. Thats not all that bad though; even HF Yagi antennas hardly have any positive gain! Whats important on mobile antennas that by their nature are small, and close to the ground, is that we need as much signal efficiency or radiation efficiency as can be managed. So, how is this achieved?
Antenna efficiency and Q are achieved by minimizing resistive losses. Resistance is accumulated within small wire conductors; this includes even the stainless steel wire or rod the antenna whip itself is made from. It is most notable in the coil that loads the tuned circuitry of the antenna. Big large diameter wire coils are much more efficient than smaller thin wire coils. Also of great importance is the resistance of the antennas counterpoise, where the antenna connects to the automobile chassis.
It is common for many Ham's these days to attempt to install all of their mobile antennas on some sort of clamp-on mechanism. The worst of these is some sort of luggage rack that has little metal surface area, and much higher accumulated resistance. These attempts at "bolt-on" installations are usually the most significant worst first step inexperienced Ham's make. Connecting the antenna directly to the metal body of the car in a nice low resistance fashion is best. Best of all is doing this in the middle of the cars metal roof. You just have to get over that concern of drilling holes in your car!
As a comparative analogy; several years ago Jerry Sevick W2FMI ran some tests with a roof top mounted tower antenna atop a building. He progressively doubled the number of counterpoise radials beneath this tower and took measurements each time. With each addition he lowered the feedpoint resistance, and improved the high current radiation of this antenna installation. We can do much the same thing on a vehicular installation by making the best low resistance mounting conditions possible, and by bonding the metal parts of the vehicles chassis and body together. Another trick is to bond the cars exhaust system in several places along its length to the vehicle chassis with short braided strap conductors.
Coil placement is also important. Base loaded antennas are less efficient than are center loaded antennas, and while its a bit of a misnomer, what are sometimes called top loaded antennas are yet even more efficient. At least this last statement is true if the coil is big and fabricated from large diameter wire! The Hustler "top loaded" antenna, and venerable "Texas Bug Catcher" are the best examples of this. Also, capacitive loading at the top of the antenna will improve its efficiency by raising the high current point further up the antenna structure. Capacitive loading above the coil itself will improve frequency bandwidth coverage.
So what are some practical antenna installations and methods of providing good mobile antennas between the frequencies of 3.5 to 54 MHz. Since I have been interested in not only HF mobile communication but, also working DX and local Ham's on the 6 meter wavelength band, I have favored the Hustler, so called, top loaded antenna. Its large surface area half inch diameter 54 inch long mast provides lower resistance than would a skinnier wire antenna, and by using the higher power Kilowatt rated coils; their larger wire size makes them higher Q, efficient tuned radiators. Also, this half inch diameter 54 inch long mast I referenced earlier forms a quarter wavelength whip for the 6 meter band. Any resonator coil above this mast is not 'seen' during 6 meter operation. This is because the coil functions as an RF Choke at 50 MHz. and higher frequencies. By this means the antenna will work on both 6 Meters, and also on whichever HF band I have a resonator coil installed for. You can even put 3 or 4 such coils atop the mast at the same time but, this extreme inductive reactance limits antenna efficiency and bandwidth.
The Texas Bug catcher is a good antenna. It is one of the best mobile performers at the lower end of the spectrum on 40 or 80 Meters. At these lower frequencies small wire coils of other antennas high resistance coils really demonstrate how bad things can get! On 10 Meters a simple stainless steel whip antenna that is 98.873 inches long (which is 1/4 wavelength, or 90 electrical degrees in length) is very efficient. This same antenna (or one like it that is 108 inches long) would work as a halfwavelength radiator {180 electrical degrees}on 6 Meters; if it was fed with a quarter wavelength transmission line transformer to provide proper impedance matching transformation.
So, which antennas should probably be avoided? The ATAS 100 is cute but, its not very good from an RF signal efficiency standard. Antennas that consist of mostly coil should be avoided. Antennas that are wire wrapped around a plastic or Fiberglas tube are a compromise antenna. They are inexpensive but, not very signal efficient radiators.
Build some antennas yourself, and see what works best. You can fabricate proto-type coils with #14 AWG solid copper wire on cardboard tubes. I use such discarded tubes from industrial plastic shrink-wrap, or smaller tubes from blank label rolls. These coils also make excellent wavelength traps or end loading coils for wire dipole antennas. These are great for Field Day and other radio field trip expeditions. Antenna tests, commonly called Antenna Shoot-Outs, are a popular competitive forum. If your club is in the local Orange County area of Southern California, I would love to help your club organize such events.
Terms used in this article
Impedance matching: All antennas whether small or large in their relative wavelength aperture must be properly matched to their feedline and exciter impedance. Even if the antenna is capable of producing tremendous antenna gain, it will all be lost without proper impedance matching.
Antenna efficiency: This would more fully be stated as "antenna radiation efficiency". Antennas vary in their ability to effectively radiate a signal. Large surface area, properly tuned antennas radiate well. By contrast, a common light bulb can be used as a "phantom antenna". It will radiate a signal, and you might even communicate with another station while using it. A good antenna would work much better!
Antenna Q: The Q or "Quality factor" of any antenna or tuned RF circuit governs how much of the signal is efficiently conveyed, or conversely, how much of it simply becomes waste heat!
Radiation efficiency: See antenna efficiency
Resistive losses: In an alternating current circuit, such as an RF circuit, larger surface area conductors minimize resistive losses. This is because AC currents flow on the outside surface of the conductor; this is called "skin effect". Hence, the more surface area the conductor has, the lower is its net AC resistance!
Loads: Coils are commonly called inductive loads. They "load" what would otherwise look like a short or capacitive circuit.
Counterpoise: All unbalanced antennas, such as mobile whip antennas, require a "ground plane" or "counterpoise" to work against. The main currents flow in the radiating whip but, without an efficient counterpoise, this does not happen!
Counterpoise radials: A home station vertical whip or tower radiator would use a wire counterpoise strung radially around its base. Kept sufficiently high above the dirt, these radials will provide a nicely symmetric and low loss counterpoise. The more of them that are used, the lower the feedpoint resistance will be, and consequently the greater the antenna efficiency.
Feedpoint resistance: In an automobile whip installation this is most practically achieved by making good low resistance connections to larger portions of the automobiles metal body. The roof is best, the trunk would be next, and a nice clean and solid connection to a fender will work well. See counterpoise radials (hint: we can't make a car into a symmetric counterpoise but, we can keep the resistivity of the connections down)! Bonding is critical if the antenna is trunk mounted. Jumper the hinges with braided straps! Actually the more straps the better! Two for each hinge, and one near each hinge side trunk corner.
High current radiation: A halfwavelength wire dipole has its high current point at its center. A "Ground Plane" antenna, such as on a car, has this high current point at its base. Actually, its at the base if the antenna is one quarter wavelength long and linearly loaded, such as a stainless steel quarter wave whip. If the antenna is inductively loaded, the highest current point will be the inductive coil itself.
Bonding: No this isn't something you do with your budd's. If you make nice low resistance bonds between welded portions of your cars body, you will lower radiation resistance, and improve radiation efficiency. Look at my article on, "The Waynis DC Connector"
Base loaded: This means physically placing the inductive loading coil near the base of the whip. This is mechanically convenient, but its bad for signal efficiency.
Center loaded: Nearly all mobile whip antennas place this inductive coil near the center of the antenna. Its about the best you can do to improve signal efficiency.
Top loaded: Some antennas are said to be top loaded, they are really (electrically and schematically speaking) center loaded.
High current point: Like I explained earlier, the high current point, or point of maximum radiation is at the bottom of a quarter wavelength whip. If though you place a capacitive "top loading hat" at the top of the antenna, you will raise this current point further up the antenna and, the antenna will be a better efficient radiator!
Bandwidth: Width of frequency coverage or bandwidth is limited by highly inductive circuits. The large inductance incorporated to make an automobile whip antenna work on 80 Meters is the best example of this. You often can move frequency by only 20 or 30 KiloHertz in an 80 Meter mobile. Adding capacitive reactance is a means to broaden this effect.
RF Choke: A large inductance provides an extremely high impedance for relatively high frequencies; this stops higher frequencies full stop, it chokes them off. Lower frequencies are accommodated with a lower resistive path in such coils, and current can flow more easily.
Resonator coil: This is Hustlers name for the means by which they provide a resonant tuned circuit on their whip antennas. It is descriptive of the function though!
90, 180, and 360 degrees of electrical length: An AC circuit of one wavelength provides 360 degrees of electrical phase rotation. A halfwavelength is therefore 180 degrees, and a quarter wavelength is 90 degrees in length. This becomes important when you start charting impedance (and current flow) at different electrical lengths along an antenna or transmission line.
Quarter wavelength transmission line transformer: This is sometimes called "an impedance inverter". In my example in this article, it would allow a very high impedance to be converted to a lower impedance suitable for coaxial feedline.
Wavelength traps: A coil in series with a conductor (such as a wire) merely provides circuit loading. When installed along with a suitable value capacitor, you can trap or stop wave travel. In other words, you can make the antenna appear electrically shorter or longer to different frequencies, even though you make no physical changes.
Dipole: Di means two, or two poles; like the poles in a motor or generator. The two poles referenced here are the quarter wavelength wires that are on either side of the feedline of a halfwavelength dipole antenna (Hint: such a dipole has a 73 Ohm feedpoint impedance; a quarter wavelength Ground Plane antenna [when the counterpoise is perpendicular to the radiating element] has a 36.5 Ohm feedpoint impedance.

Thursday, November 02, 2006

Apakah Radio Amateur?

Apakah Radio Amateur?
Radio Amateur ataupun juga dikenali sebagai ‘HAM Radio’ ialah hobi berkenaan membina, menguji-kaji & berkomunikasi melalui radio. Seseorang itu juga dapat menghugi seseorang yang lain secara individu @ berkumpulan dengan menggunakan pesawat radio yang menghasilkan gelombang magnetik.

Bilakah Radio Amateur bermula?
Sejarah Radio Amateur ini telah bermula semenjak perhubungan radio digunakan.Pada tahun 1912, Kongress Amerika Syarikat. Bermula 1914, pengguna radio Amateur telah mula berkomunikasi & mengadakan satu system penghantaran mesej diantara mereka. Di Malaysia radio amateur merupaka titik bermulanya perkhidmatan radio komersial.

Apakah yang boleh sya lakukan dengan Radio Amateur?
Tidak seperti teknologi perhubungan lain, Radio Amatur membolehkan anda berhubung dari mana-mana tempat pada setiap masa. Pada waktu bencana, Radio Amtur amat berguna terutamanya kepada agensi-agensi penyelamat. Pada ketika lain,anda juga kadangkala boleh bercakap dengan angkasawan @ membalikkan isyarat dari bulan. Anda juga boleh menghantar fail ataupun gambar secara digital. Adakah hobi lain menyediakan sebegini ciri seperti ini?

Saya Sentiasa sibuk. Adakah saya masih boleh menikmati hobi ini?
Sudah tentu! Hobi ini tidak terikat kepada sesuatu masa, tempat & pendapat seseorang. Memandangkan ia mudah dikendali ramai yang sentiasa sibuk mendapati ianya seronok digunakan & dapat mengurangkan tekanan selepas seharian bekerja. Anda & keluarga anda juga boleh berkumpul & mempelajari hobi ini.

Apakah perbelanjaan yang diperlukan bagi hobi ini (Pesawat Pemancar)?
Sebuah radio bersaizs sebesar telapak tangan yang baru mungkin sama dengan satu TV 29 inci yang berkos rendah kebihkurang RM300 –RM10000. Radio yang lebih besar sama kosnya dengan sebuah computer.

Selain dari itu, bahan-bahan pembelajaran berkeneen Radio Amateur adalah berpatutan & yuran peperiksaan bagi mendapat sijil perakuan juga adalah rendah.

Bagaimana saya boleh menjadi seorang operator Radio Amateur & siapakah yang mengeluarkan sijil perakuan ini?
Seseorang yang hendak menjadi ‘Ham Radio’ hendaklah lulus di dalam peperiksaan yang dinamakan RAE (Radio Amateur Examination). Setelah lulus barulah boleh membuat permohonan bagi mendapat lesen Radio Amateur. Di Malaysia pihak yang memegang kuasa mengeluarkan lesen radio amateur ialah Suruhanjaya Komunikasi & Multimedia Malaysia.

Hanya mereka yang lulus & diperakukan boleh mengendalikan sesuatu alat Radio Amateur
Sukatan Peperiksaan
Anda akan diuji tentang perundangan radio komunikasi, tatacara perhubungan , prinsip radio & elektronik serta mengenal propagasi gelombang & antenna

Adakah saya perlu membayar yuran?
Ya. Sijil Perakuan tersebut haruslah diperbaharui setiap tahun. Yuran tahunan bagi kelas A adalah sebanyak RM 36 & bagi sijil perakuan kelas B ialah RM 24 setahun.

Tajuk Perbualan
Seseorang boleh berbual apa sahaja pada mana-mana waktu yang jangka masa tidak dihadkan. Topik yang dilarang perniagaan, hal-hal politik, ugama dan sesuatu yang menyinggung perasaan.

Para amateur dituntut untuk membuat pelbagai ujikaji tentang radio komunikasi seperti antenna, peralatan radio & ujikaji-ujikaji lain.

Amateur diminta membantu kerajaan sewaktu kecemasan seperti banjir, gempa bumi & kebakaran.

Callsign (Kod panggilan)
Setiap Amatuer mempunyai kod @ callsign. Di Malaysia barat kod ini 9M2 & 9W2. Di Serawak 9M8 & 9W8 & di Sabah 9M6 & 9W6. 9M ialah kelas A yang lulus RAE & ujian morse kod manakala 9W ianlah kelas B iaitu mereka yang lulus RAE sahaja.

SWL (Shortwave Listener)
Sebelum menjadi seorang amateur (HAM) yang berlesen, seseorang itu menjadi SWL. Dia akan mendengar perhubungan serta mempelajari tatacara komunikasi yang betul. Anda boleh membeli radio untuk mendengar perhubungan ini.

Siapakah yang harus anda hubungi untuk mendapatkan bantuan?
Kelab-kelab Radio Amatuer terdapat diseluruh Malasyia & bersedia untuk membantu anda. Ada di antara kelab-kelab tersebut mempunyai halaman webyang mengandungi maklumat mengenai hobi tersebut kelab-kelab tersebut seperti:

Apakah yang saya boleh pelajari sekarang?
Anda boleh memulakan pelajaran anda dengan mempelajari fonetiks abjad yang digunakan oleh pengguna-pengguna Radio Amatuer di seluruh dunia:-

A – Alfa
B – Bravo
C – Charlie
D – Delta
E – Echo
F – Foxtrot
G – Golf
H – Hotel
I – India
J – Juliett
K – Kilo
L – Lima
M – Mike
N – November
O – Oscar
P – Papa
Q – Quebec
R – Romeo
T – Tanggo
U – Uniform
V – Victor
W – Whiskey
X – X-ray
Y – Yankee
Z – Zulu

Contoh Soalan RAE


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