Review Icom IC-706MKIIG

IC-706MKIIG sebuah trasnceiver radio multi band, mulai dari HF sampai dengan UHF dengan fitur yang banyak dan simppel.

Frekwensi operasi yang lebar sampai dengan 70 cm band. Tentunya All Mode (SSB, CW, RTTY, AM dan FM) dengan power full 100 watt untuk HF dan 6m, 50 watt untuk 2m dan 20 watt untuk 70cm band.

Unit PA menggunakan MOS-FET power amplifiers. Berpendingin alumunium yang tebal serta menjadi satu dengan casis dengan kipas yang besar. Dengan komposisi ini menjadikan IC-706MKIIG ini begitu stabil, kualitas output yang tinggi dengan low IMD dan emisi spurius yang rendah bila digunakan dengan full power.

Backlighting / lampu latar yang terdapat pada keys dan switch sangat membantu bila digunakan malam hari, dengan intensitas cahaya yang bisa diatur secara manual.

Tone squelch tersedia dalam mode FM untuk standar signalling. Frequency tone dapat di set untuk TX maupun RX dan repeater tone. Fungsi tone scan tersedia untuk mengakses repeater yang menggunakan tone dengan cepat dan mudah.

Tersedia Digital Signal Proccesing (DSP). Sudah termasuk noise filter dan fungsi automatis filter notch.

Bentuk IC-706MKIIG sangat kompak dengan dimensi 167 × 58 × 200 mm dan berat 2.5kg, membuatnya sangat ideal untuk kegiatan seperti DX'peditions dan lain-lain. Disain panel depan yang lebar membuat mudah diinstal di homeshack ataupun mobil.

Fungsi Automatic repeater juga tersedia dan frekwency repeater dapat diprogram dengan program khusus.

Kestabilan frekwency hingga ±0.5 ppm bisa didapatkan dengan menambahkan CR-282 HIGH STABILITY CRYSTAL UNIT.

Ada ±14 steps fungsi yang terlihat di layar frekwency dan plots signal streng untuk semua band.

107 memory channels dengan alphanumeric name.

Simple Carrier Operated Relay

Carrier Operated Squelch or Carrier Operated Switch (COS) formerly known as Carrier Operated Relay (COR).

Functions a COR like a control in Repeater Push To Talk. The difference between COR with COS only on the voltage output. COR like a Contact Point – Relay .

Now a days the radio is well known as the Solid State Cos the resulting change in value is a voltage, where the Signal received by the receiver unit at the point open squelch status will change from to Logic Low Logic High (+5 V / 0V-Ground) or vice versa.

The most easy to see from the changes in the Indicator is "Channel Busy" is usually in the form LED. Logic is what's used to drive relay, transistor or optoisolator used as PTT.

In the bottom pictures below are from the COR (cos buffer - Delay - Relay Driver) and Audio Buffer Block diagram snd repeater.

Repeater Build Up

I am currently building another repeater for our Police Departement. I've decided to document the procedure, and discuss repeaters and repeater building.

What is a Repeater ?

A repeater is a radio system that receives a radio signal on one frequency and repeats it on another frequency. Here's an example of what makes a repeater system worthwhile.

Our police department is located in a center of city Pekalongan. Most of our members have portable radios. It is hard for us to communicate with each other using the portables, since they have limited range even in the best of circumstances. The repeater at my shelter is a 30-watt repeater on a 60 meter tower. It has an effective range of ~20 km. When I talk on my portable through the repeater I effectively increase the range of my portable from 1-5 km to 20 km. Because the repeater is located on a tall tower it can receive better, also. It can pick up the traffic from the portables of the other members that normally couldn't be heard portable-to-portable.

Another benefit of a repeater is that everybody can hear what everyone else is saying. This allows for better communications. Before our department got their repeater, a deputy in one part of the county had to relay their radio traffic through their dispatcher, who then had to relay it to another officer. Now both officers can speak directly, even if they are in opposite ends of the county.

How do you build a repeater ?

The easiest way to get a repeater is to plop down the money and buy one. I'm poor, though, so I'll be building one out of discrete components. Actually, that's not a good argument. Repeaters aren't as expensive as they used to be. If I were buying new parts for the repeater I'm building it would probably cost me about the same. However, since I have old radios laying around I'll use these to build a repeater.

Here is an overview of a repeater system.

Antenna,

Receive radio,

Transmit radio.

Duplexer - Probably the least understood and sometimes forgotten component of a repeater system. A duplexer is a filter system that keeps the transmit and receive sides separate. Without a duplexer the transmitter side would jam the receiver, and the repeater wouldn't work.

There are two main types of duplexers: Band pass and band reject. A bandpass filter allows a certain BAND of frequencies to PASS while filtering out all other frequencies. A bandpass filter allows the receive frequency to pass to the receiver, and the transmit frequency to pass from the transmitter. Everything else gets filtered out. A band reject filter is almost the opposite. It REJECTS one BAND, and lets everything else pass. It allows everything but the transmit frequency to go the receiver, and vice versa. I prefer a bandpass filter. They provide better filtering for a repeater. However, they are usually more expensive. There is actually a third type of duplexer...bandpass-reject. It is a combination of the bandpass and band reject, and is used where the transmit and receive frequencies are very close together.

Duplexers normally look like long cans. The closer the receive and transmit frequencies are, the more cans you need to properly filter them, and the bigger around the cans will be. The bad part of that is more cans cost more money, and they eat up more of your transmit power and receive sensitivity.

Repeater controller - The controller is the brains of the repeater. It makes sure it receives the proper signal from the receiver, and then makes the transmitter transmit.

Wiring connections

The repeater controller needs certain signals from/to the radios to perform correctly.

COS - The COS signal tells the repeater controller that the receive radio is receiving a signal. The default source for a COS signal is the unmute for the speaker. However, some radios have a COS-type signal or a better source than the speaker unmute. You need to look at the radio schematic to determine this. Did I mention that electrical schematics for your components are vital?

Receive audio - The receive audio signal is taken from the output of the discriminator. The discriminator is circuitry which converts the signal from the carrier that goes through the air back into normal audio. Once again, use the schematics to determine the discriminator location. The receive audio from this location contains the audio that we will hear (300 Hz to 3300 Hz) and the PL tone information (60 Hz to 255 Hz). The repeater controller filters the PL tone information and compares it to the expected PL tone. If it is correct it allows the receive audio to become transmit audio.

Transmit audio - The audio which is sent to the transmitter for rebroadcasting. The repeater controller will add Morse Code ID beeps or courtesy beeps to the transmit audio if programmed for those features. This line can usually be connected to the same audio line which comes from the microphone on the transmit radio.

PTT (push to talk) - This is the same function as keying the microphone, and is connected to the same wire.

CTCSS/DCS tone input - This is an optional input to the transmitter, and is only used if you're setting the repeater up as a community repeater or shared repeater*. This line is connected to where the transmit radio would normally add the CTCSS tone to the transmitting audio. This allows the repeater controller to inject the proper PL tone depending on the user of the shared repeater.

Kenwood HF Radio Telephone TK80

The TK-80's design combines a high-performance HF transceiver with elegant user simplicity, all rolled into a tough, compact package that will deliver many years of dedicated field service.

The large backlit LCD display provides high visibility in most lighting conditions, with alphanumeric channel designations up to 7 characters, frequency, memory channel number, mode, signal meter, and transmit indicator.

Selective calling system is an option (KPE-1 required) that enables individual, group or open calling, and is ideal for distributed networks of HF transceivers.

VOX (Voice Operated Xmit) is another feature that makes the TK-80 convinient and easy to use. And with the optional PC-1A Phone Patch interface it provides telephone patch capabilities as well.

Tough aluminum monocoque chassis provides reliable performance year after year in adverse climatic conditions, from the Antarctic to the Amazon. Meets MIL-STD 810D specifications.

Internal and external antenna tuner options gives you a flexible range of antenna choices. The internal KAT-2 does not increase the size of the radio, and is ideal for yagi, ground plane and dipole type antennas. The external KAT-1 is for mounting at the base of aperiodic antennas such as whips and long wires.

CW full and semi break-in can be set with the key delay time control.

The Clarifier allows fine adjustment or receive frequency for best audio clarity, set up by the dealer in either 10 Hz or 1 Hz steps.

80 memory channels are available for custom set-up of transceiver and monitoring frequencies.

Memory channel scan features carrier-operated and time-operated modes; receive threshold for both can be dynamically controlled by adjusting the squelch volume.

Data mode at the touch of a button allows computer communications on USB/LSB at up to 300 bps in AFSK or FSK modes. Useful for data acquisition, text-based file transfers and other low-speed data communications applications.

All-mode general coverage receiver from 500 KHz through 30 MHz continuous for easy monitoring all HF bands.

100 watts output with an antenna tuner gives you the punch needed to drive any antenna system. The RF output is adjustable in 4 steps, 100W, 50W, 25W and 15W, which can be assigned to any memory channel. The maximum output is also dealer-adjustable down to 50W, 25W and 15W.

Advanced intercept point (AIP) feature expands dynamic range and minimizes cross-talk interference (dealer setting). In addition, the Noise Blanker cuts pulse-type noise and the optional 500 Hz CW filter (YK-107C) reduces interference for Morse code operation.