I purchased an iTrip while in San Francisco at the Apple WWDC (at end
of June) for use in the UK where, as far as I know, they are not
available. My experience was that it had a maximum range of about 3 ft
and the method they use for changing the frequency simply does not
work.

The device appears to draw all it power from the stereo jack. Before I
purchased it, I assumed it took power from the Firewire socket, but
there are no connections. This implies that the power output is
limited by the audio output, which it must convert to DC. This is a
bit worrying because an FM signal is constant amplitude so I dont know
it copes with low audio signal levels. On mine it doesnt seem to cope
at all.

The upshot is that the device is of no use in a car - my primary need
- where unless you can position the iPod right next to the antenna.

The method they use to change the transmission frequency is to supply
a lot of MP3 files with tune names of the desired frequency (e.g.
97.5). When you "play" the tune with the iTrip connected, it decodes
the tunes as a special instruction to change the frequency. Although
the light flashed indicating something was happening, it failed to
change the frequency.

I mailed Griffiin support but not had a reply (as yet). My advice is
not to buy one of these devices, or if you do try out the one you are
thinking of buying. It could be that mine has a fault , but I suspect
the range specs are vastly overoptimistic. It may be that the ruling
FCC limits on radiation in the FM band are simply not sufficient. The
iTrip is a good idea in principle because you can use the iPod in in
hire cars or other peoples house without pulling their systems apart.
In practice it doesnt seem to work well enough to be of any use.

In article <2a799bb3.0307161307.5da219dd[at]posting.google.com>,
john_google[at]jpy.com (John P) wrote:

> I purchased an iTrip while in San Francisco at the Apple WWDC (at end
> of June) for use in the UK where, as far as I know, they are not
> available. My experience was that it had a maximum range of about 3 ft
> and the method they use for changing the frequency simply does not
> work.

I've done 3 metres (out of the alleged 10...haven't tried further)
without issue. The tuning mechanism has not failed for me.


> The device appears to draw all it power from the stereo jack. Before I
> purchased it, I assumed it took power from the Firewire socket, but
> there are no connections. This implies that the power output is
> limited by the audio output, which it must convert to DC.

No. Look carefully at the connection. There's an additional line that is
specifically intended to support power transmission.

> This is a bit worrying because an FM signal is constant amplitude so
> I dont know it copes with low audio signal levels. On mine it doesnt
> seem to cope at all.

That may be part of the problem you had tuning. I found that for the
iTrip to work reliably (and this is documented) I had to set the volume
to a much higher level than is comfortable with earphones.


> The method they use to change the transmission frequency is to supply
> a lot of MP3 files with tune names of the desired frequency (e.g.
> 97.5). When you "play" the tune with the iTrip connected, it decodes
> the tunes as a special instruction to change the frequency. Although
> the light flashed indicating something was happening, it failed to
> change the frequency.

You also have to stop playback (again, as documented) when the light
starts flashing. The tuning tracks start with a sequence that tells the
iTrip to change the frequency, but finish with a sequence that tells it
to cancel the tuning request. The change doesn't take if it hears the
cancel signal within several seconds. This is protection against
unintentionally playing one of the tuning tracks.


G