Headphones for best S/N on Scout

[Art Searle]

Hi Scott, Rohre and group,

rohre wrote:
> 
> You must be using hi fi phones rather than communications, limited band, 300
> to 3000 Hz phones.  If you use high impedance phones, or Comm phones, you will
> not hear this noise which is the microprocessor noise.  It is only detectable
> on mine if I use very HI FI phones.  An audio filter helps, but the better way
> is to listen to HF with communications phones so your brain and ears will not
> tire from extraneous noise.  You might try better power supply bypassing on
> the audio stage if it is established that it leaks into the audio via that
> bus.  I did not go to the trouble, when I found mine worked so well with
> Military phones.

hi fi phones and most modern comm phones are low impedance and will not work well
with a Scout unless you pad them. Ten-Tec told me the phone jack on the Scout is
not a phone jack, it is a speaker jack. High impedance phones should work ok, but
where do you find them? I haven't been able to. An audio filter is not necessary.
you need to get the audio amplifier up into it's useful range. A 10 ohm resister
in parallel and a 470 ohm in series should do it. They should fit inside the
stereo phone plug.

Incidentally, Ten-Tec told me they designed the Omni 6 along the same lines as
the Japanese rigs, to work well with cheap stereo headphones.

73, de Art WU2K 

-- 
72,73, de Art Searle, WU2K, Long Is., NY, ARRL Life Member
QRP-L #524, QRP ARCI #9123, NorCal pending, DXCC MX & CW HR 
NRA Benefactor Life Member, NMLRA Life Member, AMA Life Member
NRA Certified Firearms Instructor, Dale Earnhardt Fan Club