Margaret von Busenhalter-Butt wrote:

"Mark S. Holden" wrote in message
...

Margaret von Busenhalter-Butt wrote:


Hi Mark!

How does the Harris 550 perform on MW BCB? Is it better than a Drake
R8/8A/8B ?

Thanks,

Margaret


I'm not really interested in MW Dx, so I'm not the best person to answer
this question.

There is some attenuation on the MW frequencies - If you'd like I can look
up how much and what frequency it starts at when I get home.

Otherwise, the AFC and coherent AGC work on MW.

Coherent AGC takes the AGC reading through a 500hz filter regardless of
what filter you're listening through.

It also has 126 or 130db of dynamic range. (Haven't read the manual in a
couple years.)

I almost always listen in sideband mode because the AFC and Coherent AGC
don't work in other modes. Coherent AGC won't work without AFC.

For RTTY decoding, I got better results with the AFC turned off.

One of the things I like about the Harris is the filters are kind of
wide - but they have a good shape factor, so audio quality is good, but
selectivity has never been a problem. On AM & CW you can choose between
500, 6khz and if you enjoy listening to
hets in the background, 16khz. On Sideband it's always 3.2khz.

The 550 comes equipped for ISB reception too. (Both sidebands with one
coming through the internal speaker, and the other on terminals on the
rear.)

Let me know if you'd like me to check specs for MW attenuation or dynamic
range.

Regards,

Mark


That would be very kind of you, Mark. I'm just thrilled by your desription
of its audio quality. Exactly what I want. I wonder if someone could remove
the MW attenuation.

Thanks,

Margaret



Hi

It is the sort of radio you can listen to for hours at a time without
listener fatigue.

The manual indicates sensitivity is 1.5uv max for Am, and .35uv max for
sideband. (at 10db (s+n)/n ) It just says sensitivity is reduced below
1.5mhz

The radio has half octave filters on the input - a very quick Look at
the schematic leads me to feel you could adjust or eliminate the
attenuation by tweaking the value of a 470 ohm resistor.

Dynamic range is rated at 125db.

Near as I can tell, two of the keys to good audio quality are dynamic
range, and wide filters with steep skirts.

My AOR ar7030+ also has good dynamic range, and the sideband filter I
use with it is a 3.24khz crystal filter intended for a Racal 6790/gm.
It has a shape factor of 1:1.33 The radio reads it as 2.9khz.