[IRCA] accurian receiver review - part 2 of 4

["Bob Foxworth" <rfoxwor1@xxxxxxxxxxxxxxx>]

Review of Radio Shack Accurian 12-1686 HD receiver
by Bob Foxworth    - in 4 parts

begin part 2 of 4

The rear of the receiver has a 5 VDC barrel jack, a
1/8 inch mini phono jack for Aux In, two pushclips
(marked + and Gnd) for the two AM loop wire pigtail
leads, and a Fe. F connector for the FM antenna the
user chooses. There is no internal antenna provided.
The pushclips are like those found on cabineted
loudspeakers.

The front of the receiver has the following functions:
Power (push on/off), LCD display panel with blue
backlit characters, rotary volume knob which also
supports pushing in for mode (2 AM, 2 FM and Aux in).
The 2 AM or FM ranges support hearing two pretuned
stations on each band. The volume adjust is detent
step rotary tuning, and a bar graph lights up when
the volume knob is being changed. 

The Aux In is a good match for the earphone jack of
a hand held digital recorder and provides good sound
for one of these devices.

Front panel push buttons also include "preset/store",
channel-, channel+, tuning-, tuning+, DSP, and Clock.
The preset saves your favorite frequencies but again
do not survive a removal of the power cord from the
wall.

Channel mode selects previously preset stations and
tuning mode selects any frequency by stepping up or
down (10 kHz steps) or can be held in to go to search
mode. DSP has five settings, "jazz" "pop" "classic"
"rock" and "none" which apparently just adjust the eq
and rolloff for different types of music. I believe
their usefulness is marginal and to me is somewhat
cosmetic as it does not affect the RF environment.

The clock displays date and time (12-hour) in an all
numeric format on the LCD panel. When AC power is
disconnected, the clock does not store the time, and
does not reset from any HD data stream, but must be
re-keyed each time the AC plug is connected. The
clock shows if no "artist" data is being sent. The
radio will, however, store the last AM or FM frequency
chosen, if the power is removed and reapplied. As the
intention is to have the user operate the set with the
panel power pushbutton ( a relay click is heard) this
should not be an issue.

A mini-phono headset jack is provided on the front
panel, which mutes the speakers, and provides an easy
way to get audio recordings from the set.

I did not, as of now, attempt using the remote, as it
would not add to the electronic behavior of the radio.

Radio reception.

Testing was done in northwest Tampa. With no AM
antenna connected, my locals on 620, 820 and 970 are
heard weakly, say s-3 to s-4, and 570 at threshold
level. Maybe 10 - 15 dB boost can be had by holding
the finger next to the clips and inductively coupling.

Using the loop gives good level on these local AM signals
but a faint background noise in analog mode is heard.
Rotating the loop creates maybe 20 to 25 dB of nulling
when the loop is "upright". Laying the loop "flat"
reduces pickup substantially. The manual vaguely refers
to repositioning the antenna if the signal is weak,
but has no explanation of proper loop positioning.

Many "open" (daytime) AM channels showed varying
types of slight to substantial complex noise, which
defies simple description, but serves to partially
mask weak AM signals. Test frequencies such as 590 or
640 (Habana, Cuba), WRZN 720 or WWBF 1130 were heard
with substantial degradation in s/n ratio compared to
reception with test analog receivers. The type of noise
would vary by frequency, being birdies, rumbling or
grinding. The test for sensitivity on these weak
signals showed many were uncopiable or at marginal
audible copy, when they could be copied with little
difficulty on sets such as the dx398 "barefoot",
due apparently to the reduced antenna gain and the
higher noise floor.

There is a very long AGC attack time and when the
freq is step-tuned, the new frequency is muted for
over a second and slowly rises in volume. Listening
to frequencies where several signals are present,
with pronounced beating, yields a pumping, chuffing
irregular sound that makes hearing the audio difficult.

Tests were done using a R-S 15-1853 loop. This is
the circular tuned loop that was sold a few years ago.
It was possible to get a boost in signal when this
loop was near-field coupled to the Accurian's loop,
but the tuning was not sharp or distinct, and had
to be adjusted carefully and slowly, as if the front
end of the Accurian was almost "fighting back", an
effect I have never seen before and find hard to
describe. I have not yet attempted to completely
substitute a different loop in place of the stock one.

There were some AM frequencies that were relatively
noisefree and once, I had a hearable copy on Jamaica-720
a little after sunset.

The summary for AM is that (1) I don't think this
receiver is acceptable for DXing non-HD stations in
analog mode and (2) does not have the sensitivity
to get a usable signal from a HD station outside of
its local coverage area. It gives a mostly acceptable
quality for local, strong non-HD AM signals. I did
notice the artifacting on AM HD signals such as
with the Limbaugh and other talk shows. I'd rate
it as slightly annoying for any extended time.

I foresee a marketing issue where a set buyer may
believe that every AM signal will be received in
the enhanced mode that HD offers, when in fact
the great majority of AM signals may actually
sound worse, due to operating non-HD and from the
noise issues I experienced.

end part 2 of 4

_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx