Kima Makes Rebroadcasting Fun - Radio World

Kima Makes Rebroadcasting Fun

When products like the Kima were first promoted, the dot-com boom was at its height. Times have changed. But the idea of a device that allows you to monitor Web audio, independent of your PC, is still appealing
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Product CapsuleThumbs up:

Easy to insert between sound card and speakers.

Signal attenuator and LED display.

Generally, a fun device.

Thumbs down:

Cannot go 1,000 feet under "normal" conditions.

Antenna on receiver unit cannot be moved.

Limited to rebroadcasting on 88.1 and 88.3 MHz.

For more information contact the company in Illinois at (708) 583-9600, fax (708) 583-1122 or visit the Web site at www.akoo.com. When products like the Kima were first promoted, the dot-com boom was at its height. Times have changed. But the idea of a device that allows you to monitor Web audio, independent of your PC, is still appealing.

When I opened the box containing the Kima wireless audio system from Akoo.com, I was surprised. The two units were much smaller than I expected. I thought each unit was going to be about the size of a laptop computer.

At its widest point, each one is only about five inches by four inches – about the size of a portable CD player – and about as tall as a Sony Memory Stick. Each unit weighs less than a pound.

Send and receive

The Kima system comes with a base unit for sending audio from a source such as a computer and a receiver unit to transmit that audio to a home stereo or portable radio. The specifications on the box claim the signal, which puts a signal up between 902 and 928 MHz, can reach up to 1,000 feet.

I wondered how it accepted audio directly from a computer, how far it could actually transmit and how clear the signal would be. I had read complaints that it would interfere with regular broadcast signals as the receiving unit retransmits the audio over an FM frequency, so I wanted to check that out.

The sending unit has a 1/8-inch female plug for accepting audio. It does not use a USB or SCSI port to accept digital audio directly from a computer. It relies instead on a sound card for conversion to analog. Another 1/8-inch female jack is added for audio throughput. To insert the Kima between the sound card and the external speakers found on home computer systems is simple.

When I checked the parts list, I saw a DC power supply was to be included. I could not find it at first, but the power wall-warts and 1/8-inch male-to-male stereo cable turned up underneath the Styrofoam packaging. The unit can also be run on four AAA batteries.

I hooked the base unit to the output of the sound card on my home computer and hooked the receive end to my home amplifier using the RCA outs. It worked fine for the 15 feet between those two points. MP3-encoded music on my home system sounded better than the speakers on my computer.

The base unit has a five-segment LED and an attenuator that does not affect the signal going through the unit to the external computer speakers, along with a power button, power LED and low-battery LED. A switch on the back labeled A though D changes the frequencies. Information about which frequencies went with each letter was not available anywhere.

The receive unit also has a five-segment LED, a power button (without an LED to indicate power), low-battery LED, along with a button marked Scan and a stereo LED. It was obvious when the receive unit was scanning the right set of frequencies, as the stereo signal LED would light up after a few seconds.

As I could hook the transmitter up to anything with a 1/8-inch out, I tried a portable CD player. It is easier to move a portable 1,000 feet than a desktop computer and linear digital audio sounds better than compressed MP3 audio.

Quality similar to FM

The specs on the box claim a 50 Hz to 15 kHz frequency response with a 55 dB signal-to-noise ratio, less than 2 percent audio distortion and at least 25 dB separation. To my ears, the performance sounded as good as an analog FM signal.

I noticed when I switched my Onkyo tuner/amplifier between the RCA inputs and the tuner the retransmitted signal had a mid-frequency boost that I did not like. The RCA output sounded much closer to the original signal than the retransmitted one.

The receive/retransmit unit can be switched between 88.1 and 88.3 FM. Where I live, I cannot pick up any signal at 88.1, but 88.3 is jazz powerhouse WBGO(FM) in New York.

Rebroadcasting at 88.1 bled over to 88.3 and I could not pick up WBGO. At 88.3, my tuner had problems as it tried to find both the Kima and radio station, although the Kima signal was a bit stronger.

Just for kicks, I unhooked the antenna to my tuner and the retransmitted signal was strong enough to be picked up, but the radio station was not. Retransmitting at 88.1, the signal was heard when I tuned up to 88.3. When broadcasting at 88.3, however, I could not hear anything on 88.1.

With the antenna hooked up again, I walked around my room to see how far I could go without the signal fading. Five feet away, the signal would sometimes fade, but at other times it was fine up to 20 feet away. The stereo indicator on my receiver would stay lit until the signal between the units had problems.

Those who are afraid the retransmitted signal will interfere with standard broadcasting stations can simply turn the Kima off when it is not used. The retransmitted signal could only go five to 10 feet and certainly could not interfere with a radio in the next room.

Next, I put the transmitter in a room down a flight of stairs about 100 feet away. This is equivalent to putting the transmitter in a living room and the receiver in an upstairs bedroom down a hall.

The signal was not very strong. Because the antenna is permanently mounted to the top, I held the receiver unit sideways to get a clear signal.

Then, I moved the transmitter down a second flight of stairs to a room about 250 feet away and could not pick up any signal through all the walls.

How far can it really go

As a final test, I left the transmitter in a third floor room and carried the receiver to my car parked about 300 feet away. I did not receive any signal at my car.

I moved the transmitter to the front porch. With the receiver unit sitting on my trunk next to the car antenna, I carefully drove my car down the driveway. I made it about 300 feet when the signal died.

I found it interesting that the signal remained strong until it died altogether, as if a gate circuit had cut the audio once the signal fell below a certain level. Unlike conventional FM, there was no gradual loss or erratic intermittent signals one might expect when moving out of range.

I do not believe the signal can go 1,000 feet – maybe in a flat desert with few objects, true line-of-sight or other radio signals to interfere. I recommend using the Kima across a room or between two adjoining rooms.

With a list price of $99.95, the Kima is more expensive than a long cable to get audio across a room, but is considerably more fun.

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