[IRCA] Hot-Rodded Sony ICF-SW7600GR Performance Report

[D1028Gary@xxxxxxx]

Hello Guys,
 
     The Sony ICF-SW7600GR is compact digital SSB  portable with reasonably 
good MW performance, using a stock 4.75" x .37"  fixed-coil loopstick for the 
530-1700 kHz frequencies.  At $134.80 plus  shipping from Amazon.com (via 
Gigabargain), it has excellent Synch detector  function for a portable, as well as 
decent shortwave performance.
 
     Having a sudden need for a very compact  SSB-equipped MW portable to use 
as a "spotting receiver" for South Pacific DX  targets during a short 
Ultralight Radio DXpedition to Grayland, Washington, I  became intrigued with the 
idea of replacing the SW7600GR's stock loopstick  with a 7.5" Amidon ferrite bar, 
wound with 40/44 Litz wire.  This  combination of MW frequency-optimized 
ferrite and Litz wire has provided  huge sensitivity gains not only in the 
SRF-39FP and E100 Ultralight models, but  also in the larger ICF-2010 traditional DX 
portable.  Upon checking the  stock SW7600GR loopstick, it was found to be a 
smaller-sized copy of the  ICF-2010 loopstick system, having a fixed 
(non-alignable) larger coil and a  smaller tickler coil, to optimize spurious signal 
rejection.
 
     The SW7600GR loopstick was easily replaced  with a 7.5" x .5" Amidon 
ferrite bar-based antenna, wound with 40/44 Litz wire  to match the 983 mh 
inductance of the stock main coil.  The  sensitivity improvement was very dramatic, 
boosting the weak-signal performance  of this compact portable past that of a 
stock ICF-2010.  This was a total  reversal of its performance prior to the 
modification, in which the  SW7600GR was clearly inferior to the stock 2010 on 
all MW frequencies.
 
     At Grayland, the newly hot-rodded SW7600GR  performed very well as an 
SSB "spotting receiver," with different TP  station frequencies stored in 
memory, easily accessed by pushing single  buttons.  SSB carrier strength of the 
"targets" could be quickly  checked, and the direction of the received signal 
could be easily determined by  the new loopstick's excellent nulling ability.
 
     On the domestic frequencies, the newly modified  SW7600GR provided lots 
of sensitivity, with easy loggings of KPUA-670 and  KGU-760 in Hawaii.  For 
the 9 kHz split targets in the South Pacific,  however, the modified SW7600GR's 
sensitivity alone wasn't quite adequate to keep  up with the modified Eton 
E100 Ultralight, which had a Murata  CFJ455K5 premium ceramic IF filter installed 
(the same narrow filter as in  the Eton E1).  The modified E100 could split 
off Fiji-639, Tonga-1017,  2ZB-1035 and 2YA-567 significantly better than could 
the modified SW7600GR,  which had to contend with more domestic slop.
 
     Despite this, the compact Sony's function as an  SSB "spotting receiver" 
was excellent, and it directed the AM-mode  only Eton E100 to the "hot" 
frequencies very well.  9 kHz SSB carrier  strength can usually be checked even in 
the presence of domestic splatter,  and the SW7600GR was great for this 
purpose.
 
     For domestic DXers, this modified ICF-SW7600GR  would provide a great 
sensitivity improvement over the stock model, for a very  reasonable cost in 
parts (under $30 for the ferrite bar, Litz wire and other  items).  The 
modification is easy to perform, and the unit remains  very compact (a photo is on the 
Ultralightdx Yahoo group site in the "Roll Your  Own DXing Monster" album).  
Nulling ability is excellent, and the  loopstick's external mounting provides 
extremely quiet reception compared to the  stock antenna, crammed as it is 
inside a cramped cabinet next to the SW whip  antenna.  The full modification 
article should be written shortly, for  those interested in this impressive 
performance upgrade. 
 
     For serious 9 kHz split-frequency DXers, however,  a premium IF filter 
upgrade would be very helpful in chasing TP's and  TA's next to domestic 
splatter.  The good news is that with an IF of 455  kHz, the ICF-SW7600GR can be 
modified with the same premium ceramic filter that  has transformed the tiny E100 
into a DXing sensation this summer.  Well,  there's always a nice-to-do 
project that is on the drawing board...
 
73,  Gary  DeBock      



**************Looking for a car that's sporty, fun and fits in your budget? 
Read reviews on AOL Autos.      
(http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 )
_______________________________________________
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