On Sat, 17 Apr 2004 02:55:43 GMT, "Z.Z." wrote:

Bill Brannick wrote:

...
So.. if that telecoil can pick up RF from a cell phone, what is the
potential for it picking up RF from my own HF transmissions
here...(probably not all bands, but... )????
...

The telecoil doesn't really pick up RF from the phone. Digital phones
cycle on and off in the audio range (teens of kHz) and it's the hash from
the switching that the coils pick up. They're optimized for a fairly
narrow freq range to match the passband of telephones. The old analog
phones didn't have that problem (at least I never noticed it) on the same
freqs and usually with migher power than the digital phones. I've never
noticed any problems with RF in the HA's but the telecoils are sensitive
to other fields, esp. from computer monitors or any other audio freq
emitter (TV's, transformers, flourescent lights, some of those anti-theft
thingies they have in stores that you have to walk thru, etc.).). I
suppose if you worked really, really LF (20kHz) you might have some
issues but even then only when the coils are switched in (they're not
active all the time...you have to switch them on). Actually, the cell
phone I have now (Motorola) works fine without the telecoil, it's just
kinda touchy where you have it positioned...you gotta get the phone
speaker lined up with the mic on the HA. Also, Moto and Nokia make loop
adapters that you wear around your neck and plug into the phone and
couple with the telecoil...they work pretty well and get the phone away
from the HA and make it kind of hands-free (I suppose they'd work with a
radio if you wired up a little adapter...hmmm.....).

Be patient with your new HA's...you'll be overwhelmed with sound for a
while...stuff you haven't heard for a long time. It takes a while to re-
adjust. The world is a lot noisier place than you remember :-) It'll
take a few visits to the audiologist to get them set up so be prepared to
work with him/her. And if you're getting digitals, look into the noise
reduction capabilities...it'll make the bands a little quieter...

Good luck...

73... Mark AA7TA

The noise generation from the power supply is more of an issue with
GSM and TDMA technologies. The GSM/TDMA handset transmits 217 bursts
of data per second, so the switching power supply has to ramp up for
the transmitter 217 times a second. The 217 Hz noise is more
noticeable when the handset is located far from the cell tower and the
transmitter is pumping out maximum power. CDMA does not pulse the
transmitter and, therefore, should not have the buzzing problem.

Regards,
Ed Bailen - N5KZW