The
Japan Radio Co. NRD-505 Receiver
JRC
NRD-505 HF Receiver (1977~79)
(picture
edited by Dave Z)
The
Japan Radio NRD-505 receiver was built between 1977 and 1979 and
was not produced in large numbers (about 1000). For those days a
steep price tag of almost $ 2300.00 was very hard to inhale. It's
matching NVA-505 speaker and 4 channel memory board (CD4-8) unit
were both options. No internal speaker. It used a PTO tuning
circuit, just as the Drake R-7/TR-7 sets of that day did . But
the PTO used in the 505 put the Drake's to shame (MUCH better
built) !!! And of course the drift factor in the Drakes were
nasty....505's had no such of a excessive problem.
The 4 channel memory option stored frequency only. A collectors
set these's days as the later NRD-545 overall will be a MUCH
better deal (and performance) than any overpriced used
NRD-505's. But for it's day it was a most intresting set. I have
never had the chance to even see one of these in person, so input
from others below.
Enjoy.....Dave N9EWO
"great
lost perfect set ? Probably not, but it sure is fun to
use"..........Paul Bigelow
(picture
edited by Dave Z)
Top
view of the JRC NRD-505 innards, you can eaisly see the PTO unit.
(picture
edited by Dave Z)
Information
from Paul Bigelow on his NRD-505. Thank You Paul.
Physical:
Constructed like other JRC receivers. Robust, solid and
with vertical cards that plug into a motherboard. Each
card is separated by a shield. All aluminum construction
for panels and chassis. Knobs are plastic. The VFO is
(probably) permeability tuned much like the old Collins
equipment.
Reception (compared with AR7030):
Sensitivity - about equal, the JRC has slightly reduced
sensitivity below 1600kc. The JRC may be a bit better on
SW bands.
Selectivity - good, the AOR is a bit better but the
narrow mechanical filter of the JRC works well. The
narrow CW filter works very well. The filters can be
adjusted so the JRC performance may be improved upon. All
in all though, the AOR is better.
Sound - JRC, but not horrible. It is a bit hissy but the
noise is NOT coming from the amplifier but the IF amp, I
think. Since someone misadjusted the IF gain to maximum
gain (not good) the noise can be reduced with proper IF
gain adjustment. The AR7030 wins (of course).
Overload - A bit of overload on Longwave from AM stations
and on the 14MC band from STRONG 7MC stations. Again,
proper adjustment of the mixers may help in this regard.
Still, not bad. The AR7030 is better.
Birdies - A few small ones but have not tried a REAL test
yet. The JRC will probably win in this regard.
Tuning smoothness -- very smooth in places, 10
revolutions for each 1MC band. It uses nylon gears fitted
with anti-backlash gears.
One big BEWARE concerning the construction of the
NRD-505. The connections from the chassis to the front
panel is not by ribbon cable (like the NRD-525) but
rather by flexible ribbon film found today in camcorders
and cameras. VERY high-tech for the day (1977) but with
age it can get fragile and is difficult to repair. Mine
has no problems but the slightest nick in the film or a
wayward drop of solder could lead to a BIG headache.
The 4-channel memory seems to work well, if a bit crudely
by today's standards. It only stores the frequency -- no
mode information. It does have a provision for keeping
the memory when the set is unplugged via a battery (on
the circuit board, like the NRD-525).
The bandwidths are:(3 filter slots)
6kc - Ceramic filter AM-wide. Sounds pretty good -- not
the highest sound quality but not too bad either.
2.2kc - Mechanical filter SSB and AM-narrow. Works well
with SSB. AM is pretty muffled but intelligible.
.6kc -(option) Mechanical filter CW. Works well with
Morse code and provides a quiet background.
There is also an audio filter that switches in during CW
mode and maybe SSB that restricts the audio highs and
lows and reduces the hiss.
The mode selects the filter but there are positions for
AM-Wide, AM-Narrow, USB, LSB, CW-Wide, CW-Narrow, RTTY.
Found the correct battery for the memory card. $8.50 --
ouch! Silver oxide camera battery.
Is it the "great lost perfect set"? Probably
not, but it sure is fun to use.
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