Soundfeeder SF100 FM Audio Transmitter

Submission by Matthew – My quest for a useful audio transmitter continues.  After the disappointing performance of the Kiiro audio adaptor I was pointed in the direction of ARKON who make, amongst other things, various devices for using various devices in the car.

They make three products that transmit an audio signal via radio to an FM receiver called sound feeders. The soundfeeders came in three flavours, the SF100, which came with a car cigarette lighter plug, the SF120, which looks like a small transistor radio – complete with telescopic aerial (remember them?), and the SF121 which seems to have been designed for connecting to PDAs.

I bought the one with the cigarette plug as in the car it’s one less thing to feed with batteries. I bought it straight from the Arkon web site and it arrived on the mat for about £36 but I didn’t get charged any duty. It arrived quickly about a week after ordering.

The unit comes with a lot of wire attached. There’s the wire to the lighter plug, a jack plug for the audio in and a power out lead. This is great as it allows you to use the Soundfeeder to power your audio device as well. Although I get great battery life from my minidisc this was an unexpected bonus. It comes with a standard plug on the end with a collection of various dc plugs that it connects to. One of the multiway slider switches on the unit itself selects the voltage that you require. For my application this was great – but for other HA types of use it might be less useful. If you were using this in a home environment it is nice that you could cut the cigarette plug from the end and power the device from a normal wall wart. You would probably have to make sure that you used a regulated smoothed power supply to power the device though. You probably would not need to use the dc output, unless it was useful to power something else. The website suggests that this device is not powerful enough to drive a PDA as they require more power.

The unit is black, plastic with white writing on the controls. Although bigger than the Kiiro the unit feels slightly better built and robust. The lack of a battery compartment is one less thing to break. The plugs are moulded on and the cigarette plug is of a reasonable quality, not the best but also not the worst that I have seen.

A trip to the car followed to set the thing up. In goes the cigarette plug, and a red LED lights on the sound feeder. The minidisc gets connected via the jack plug and I press play. 10 minutes later I’ve yet to find the signal. It must have been hiding under a local station. So I have to try another way. I tuned the radio around until I found a patch that wasn’t being used locally – 106.4 MHz – it was quite a pain to get my Sony stereo to do this – I had to revert to the manual to find out how NOT to do a scan tune. The other controls are then on the sound feeder. You tune the sound feeder by means of a band switch which selects one of four blocks between 88 MHz and 108 MHz. You can then fine tune this via a rotary control on the side. Setting it to the last block which contained 106 MHz, moving the fine tuning dial I was able to find the signal straight away. The signal is strong, and I had no immediate problems with the stereo loosing the signal and de-tuning as I did with the Kiiro.

After using this for a few months in the car, I found a couple of problems. As you drive around the country, sometimes other local stations get a bit too close to 106.4 MHz, and you can hear two signals which can get a bit confusing. As you can retune the Soundfeeder to the entire FM band, this isn’t too much of a problem. Also, if you are in one of these areas, a voltage drop in the car (such as a brake light coming on when you are idling in traffic) can cause the device to drift slightly, requiring a slight retune in the fine tuning. The same can be said of when you first use the unit when it has been in the car on a frosty night, there tends to be a slight drift until it warms up. Normally this is not a problem; it just depends on where you are in the country.

If you were using the Soundfeeder in a fixed location as part of a House Audio system, most of the above would not be an issue. When the device is working in the car, a metal box, on the front drive, I can pick up the signal in all rooms of my two bed semi on a cheap walkman FM radio. So correctly sited within a house this should be useful to send audio to radios throughout a bigger house. I’ve not walked down the street seeing how far the signal goes though, as I still remember the looks I got when I was using net stumbler and a laptop to see how far my WiFi went…

At some stage I will cut all the wires and re-attach the plugs so they are a complementary length to my set up – but there is always the worry that the leads are acting as an aerial and this will change the performance of the unit. The long leads mean that I can stash my minidisk under the car seat and control it with the remote. Its one less thing to fall off the dash when I brake hard. The soundfeeder has however bounced around the car quite often, has been trod on and generally abused by the kids, but seems to still work well. I doubt the Kiiro would have survived this.

I wont be returning this gadget – its been a lot of use and exactly what I wanted. Someone else in the family bought one as well and has had similarly good results.
www.arkon.com   :   FM Transmitters

2 Comments on "Soundfeeder SF100 FM Audio Transmitter"

  1. Hi,

    I have the Lenoxx SF100 SoundFeeder and would love to get him working again, but someone has cut the wires back at the circuit board. Labeling on the board is on J1, J2, J3 etc. As it pipes out different voltages etc. would love to get my hands on a circuit diagram. Any chance you know where I’d get one? I’ve been looking for some time.

    Cheers in advance.

    Tony.

  2. Peter Hemsley | February 22, 2016 at 3:53 pm |

    Are you still looking for the sf100? I’ve just found one in my loft. The DC output connectors are missing but you have them from your original. You are welcome to mine, just pay any postage.

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