N9EWO
Review : |
The
ICOM IC-7600 is improved over the
IC-756 Pro
and Pro II's
as a SWL receiver (but it still has issues).
Lower audio distortion and increasing the widest "AM mode"
bandwidth to 10 khz along with making it variable (was only 3
presets with AM in the PRO II and IC-746PRO). Separate Bass and Treble controls
also help the cause. LCD display backlighting now uses LED's for
much longer life . Major downside for SWL use is the internal fan
runs "loud" and can run continuous in a warm room in
just RECEIVE ONLY use . If the input voltage is a bit lower (12.0
volts) , the fan may cycle on/off with the lower cabinet
temperature this will give . "Receive Only" operation
is unaffected . A later discovered nasty with OUR test sample was
"manual" ECSS reception (AM signals zero beat in USB or
LSB) is not very usable with intermittent ticking DSP artifacts (see
text). (N9EWO
Photo)
Model
: ICOM IC-7600
Country Of Manufacture : Japan (Osaka)
HM-36 Hand Microphone : China
OPC-1457 DC Power Cable : (included the new version with
fuse holder changes see text)
Firmware Version Tested : 1.11
Serial Number (approx.) of Test Sample : 02033xx
Optional Accessories Tested
SM-30 Desk Microphone : China
JRC NRD-545 Receiver, Icom IC-746PRO, IC-756 PRO II and IC-756
PRO Transceivers and Icom IC-R9000 Receiver models have been
used/tested
for comparisons in this report.
DISCONTINUED PRODUCT
N9EWO's
Review on the Icom IC-7600 DSP HF / 50 MHz Transceiver (for SWL
Use)
Another Different Kind Of A Report Here........
Is ICOM's 4th try with this series DSP transceiver a winner ?? We
are going to have a look at it here, but on the side of the fence
as for monitoring
general SW / HF broadcasting stations. So if you are looking for
a detailed report with "amateur radio" TX / RX use, you
will have to look elsewhere . However, I will cover a few topics
on the TX side of the fence as well, but not in any huge detail.
You will see me make reference to the older and now all
discontinued IC-746PRO, IC-756 PRO
, IC-756
PRO II (as tested) , Japan Radio Co. NRD-545
DSP receiver
and the 2 samples of Icom IC-R9000 HF-VHF-UHF
Receiver that I have owned or used over the years in the review
below.
So you are not a Amateur Radio Operator, eh ???
I have heard of a MANY IC-746PRO, IC-756 PRO, IC-756 PRO II and III's being
sold to people that will NEVER transmit on it. Yes..."Short
Wave Listeners". With manufactures curtailing tabletop
"receiver" production, My gut feeling is this will be
on the increase. You can usually get a better deal with more
features in a Ham transceiver and the lack of tabletop receivers
these days. Well not entirely as it is not all red roses for
"SW Broadcast Monitoring" when say compared to a JRC
NRD-545 (lack of sync detection to name one), But I'm sure many
HF transceivers have been sold to non-hams, like it or not.
So What's The Draw For a SWL Type To The IC-7600 ??
/ Uses LED Backlighting - LCD Display Problems No More !!
The biggest draw is the real nifty and large "Spectrum Scope"
Display that allows for viewing of a chunk of the HF spectrum up
to 500 khz max (+/- 250 khz). This is a huge
improvement to the older PRO, PRO II and PRO III models that only
did 200 Khz max. No it's not as wide as the IC-R9500 , but is not
a big loss. Works very well and helps from missing signals as you
zip across the bands with the knob. Many will fall in love at
first sight with this one. Also the IC-7600 allows for 2
different types of tuning with the scope. One type where the
center of the tuned frequency moves with the dial and the other
and "new" way where the scope stays fixed and you tune
a red marker across the screen. The desired tuned segment here is
adjusted in the menu's (very easy to do). Scope sensitivity is a
bit lacking however as compared to the older IC-R9000 (you will
miss weak signals say below 4~5 S units), but is still very
useful and just fun. One can even change the color of the display
"scope" (personally I like green). Also a background
"ghost" display will indicate what have been received
until you tune again with the knob when it then resets (this can
be turned off). This is all in REAL time, so no receiver muting.
The IC-7600 will not have a problem with CRT burn as it uses a
full color TFT LCD and even better yet uses LED Backlighting !! This is an area that
Icom finally did it right on the 4th try !!
The IC-746PRO, IC-756PRO, PRO II and PRO III's all use a "florescent tube"
CCFL backlighting and are much more open to failure problems (which
they did and still do) !! The "Band Scope" width above
30 MHz the IC-R9000 was pretty much useless anyway, too narrow
for VHF-UHF uses. And being I'm not into VHF-UHF monitoring much
at all, I never used the spectrum scope above 30 mhz on my R9000's
when I had them. There is also a nifty screen saver on the IC-7600
with 3 different selections. It also may be turned off if desired.
Viewing angle has also been greatly improved over all other older
LCD models.
The later IC-R9000's that were made (the "L" version)
used a "CCFL backlit" LCD display instead of the CRT .
It was monochrome only, and I hear the resolution was really poor
as it was NOT a TFT type (however we have never seen one). LED
backlighting is not even used with the super expensive IC-R9500
receiver, IC-7700 or IC-7800 transceivers (all still use the now
outdated CCFL and problem prone backlights) !!
Much Improved Shipping Box / Included Accessories
Icom's weak shipping box construction the plagued the original IC-746, IC-756 PRO-2 and
other older Icom models in this series has been totally fixed
with the IC-7600. It had used a weak single wall box with no
major protection. If a dealer did not pack the set properly with
another double wall outside box and PROPER use of foam peanuts..it
could very easily get damaged. My PRO-2 sample almost got whacked
by UPS totally as the dealer I ordered mine from did not really
pack it correctly . With the IC-7600 , Icom uses TWO double wall
boxes with a nice air gap and foam on the corners in between them.
For the huge investment they did good here and made me feel warm
and fuzzy inside even before I turned it on.
Just as with the elder IC-756 PRO II , the LCD had a screen
protect plastic "peeley" over it's lens to prevent it
from being scratched during production, and is a excellent idea .
JRC did not do this with my late 1999 vintage NRD-545 . My one R-9000
I purchased brand new also did have this.
Included in the box was the HM-36 hand mic (sadly it was a dreaded made in China one), a
very nice new style 4 pin-DC power cable that uses blade style
fuses, ONE 1/4 inch stereo plug and 3 extra fuses (two 30 Amp
ones for the DC power cable and one 5 amp (internal power fuse)
and that is it . Icom does NOT include any plugs with the set for
the rear 7 and 8 pin DIN accessory sockets. So you will have to
purchase these separate if you don't have any on hand .
General button "feel" varies a bit depending where. As
others have pointed out elsewhere on the internet, it's not as
solid as the PRO series and I agree. The painted buttons have the
very simular "cheap" feel to the JRC NRD-545's , that
is most of them have a loose "wobble trait" to them.
Good "tactical feel" response at least. But don't
expect to match the old IC-R9000 or IC-781 here for overall build
quality.
Does not use the old style analog type meter. It has been
replaced with a "faux" electronic type on the LCD . At
first thought I was worried that I would not like this
arrangement ? But in real use I found it to be more accurate and
easier to see , so yes this is an huge improvement in my view.
You also have 3 different ways to view this meter (standard,
edgewise and bar types) as well as the meter response. As with
the elder models one can view all transmit meters using the
"Multi-Function Meter" bar selection including transmit
current , a general voltage at the power amplifier and
temperature. Located on the rear panel is a jack to add a after market
analog type meter. LDG made such a beast for the IC-7600 at one time
(now discontinued, not tested). It's HUGE however and a bit ugly to my
eyes.
The LCD display is simply breathtaking. As compared to older PRO
models, it is indeed a bit larger. Perhaps not quite as sharp
looking however (a bit more blurry), but it has a much greater
viewing angle (so a trade off here). I can view the display well
off the sides where as with the older models.....forget it.
With the old Icom 756PRO series and the CCFL backlights, you needed to wait awhile for the LCD backlighting to become stable for maximum brightness. With LED backlighting being used in the IC-7600 this wait is no longer required. Also the brightness is even across the entire surface (unlike the IC-756 PRO II). Only real display setting is brightness now which we set at 11 for our eyes (much less than default) . Gone are the contrast and horizon adjustments. Spectrum Scope is loaded with "Grass" which does not exist with improved later Icom transceiver's like the SDR IC-7300 (as tested here). (N9EWO Photo)
Spectrum Scope works OK. However it's not quite as sensitive as covered earlier. It takes a around 4 s-units of signal for SPECTRUM SCOPE to show up under most conditions . Now you can view up to a 500 KHz span of spectrum (250 +/- either side). It was only 250 max (125 +/- either side) with the older PRO models. The scope "att" (attenuation) feature is most handy when the band is noisy on lower frequencies at night and just stronger signals in general (say the 49 meter band).
A background "ghost" part of the scope display shows
previous activity and resets when you start tuning again. User
can change the spectrum scope color and the "ghost"
display in the menu's. Also the IC-7600 allows for 2 different
types of tuning with the scope. One type where the center of the
tuned frequency moves with the dial and the other and "new"
way where the scope stays fixed and you tune a red marker across
the screen. The desired tuned segment here is also adjusted in
the menu's (very easy to do).
Rear feet are of a Rubber type (unlike with the IC-746PRO and IC-756PRO II where it was just
hard plastic). The
front feet and pop out raised feet use some kind of a foam
cushion feet affair and sadly this foam tends to deteriorate with age.
Variable Control's / Encoder Feel / Push Buttons /
Painted Knobs
Is generally good here overall with all controls just as
with the elder PRO models, however we must cover a few points
here.
The COPAL "custom made" magnetic encoder used for the
"main tuning" is very good. It has a generally very
smooth feel. However here we do notice a bit of encoder bearing
slop. So it has some "up down - side to side" play.
Mind you it's not at any serious amount, but it's NOT in the same
excellent quality as the JRC NRD-545's magnetic encoder for dial
tuning. There is a 3 selection knob drag "break"
adjustment on the bottom end of the tuning knob (only 3
selections is a bit lacking here to me). You guessed it, it's not
as silky smooth as the encoder used in the NRD-545's main tuning
encoder even at the far right adjustment, and not even as good as
the elder models for a "really loose" knob feeling (but
close), again this is OK and not a downside.....but for the
record.
A side note to this, there are NO set screw(s) used for the main
tuning knob . It uses the low cost "push on" system. So
more than likely this is where most of the encoder slop is from (and
perhaps varies from sample to sample) ??
There
is a 3-selection knob drag "break" adjustment on the
bottom end of the tuning knob (with only 3 selections is a bit
lacking here to me).With our sample we did notice a bit of
encoder bearing slop. So it has some "up down - side to side"
play. This was not excessive thank goodness. Sorry, it's not as a
silky smooth magnetic tuning encoder as used in the NRD-545's
even at the far right adjustment as shown above.
(N9EWO
Photo)
"Smooth"
mechanical encoder used for the RIT / XIT adjustment has a slight
weird feeling as I rotate it. You can lightly feel the encoder's
internal contact(s) engaging. This is a hard one to explain, but
so far has no ill effect and just seems to be the way it is. Many
will be pressed to even notice this one. But again this is of
real little moment and was also noted on the tested standard PRO
and PRO II versions as well.
With the exception of the RIT/XIT and Twin PBT encoders , 3 of
the front panel controls are stacked analog "pot's" .
They all turn easy enough and the knobs are larger over the PRO
series sets ,but as it usually is with stacked controls the
center control "knob" all have a slight amount of the
dreaded rotational play. That is as you go from one direction to
another, you feel a gap before you really start to go the other
way.
ICOM still makes it more of a chore to enter a frequency directly.
Not only do you have to push a button to begin to enter a
frequency directly, you also must enter the "."
(dot). So you are forced to enter a MHz frequency (or you can
enter 2 extra "00's instead). JRC allows either KHz OR MHz
with out the extra buttons. So again, 2 extra buttons you have to
hit on the ICOM. But this is a Icom trait that continues to be
handed down, and was ditto on the R9000 as well.
The stacked mechanical encoder that is used for the "TWIN
PBT" adjustment is a "click type" and has a good
feel to it with no problems (only slight rotational play with the
center knob that does not bother me being the PBT control).
Icom's IC-7600 as does JRC NRD-545, still makes use of "painted"
push-on plastic knobs. As I have indicated elsewhere on this web
site, this is not a real good idea as this paint could indeed
wear off with use. Oh humm....when we see this one go away ???
Save the paint and leave them "bare" as JRC did on the
old NRD-525. The main tuning knob is of a lower cost "push
on" type as well (uses no set screws).
Even with the direct keyboard entry being not so easy, I still
find the ICOM IC-7600 to be a very pleasant set to use with
excellent ergonomics. The menu screens on the LCD make it a real
enjoyable trip around. Enough buttons for easy access for all
functions. Certainly night and day to the AOR AR7030 receiver
"nightmare" box.
DSP Detection / Bandwidth and AGC
With the old IC-746PRO, IC-756 PRO 2 and PRO 3 models with AM mode signals you ONLY
have 3 FIXED choices, 3, 6 and 9 kHz. In the
case of the IC-7600 you now have a variable adjustment (in
200 hz steps) from 200 hz right up to 10 KHz . So this is right in line
with the NRD-545 now with AM mode filters. Sadly the SSB top
bandwidth is still 3.6 khz maximum (in 100 hz steps) and still
very limited on the higher end as when compared to the JRC NRD-545
on LSB and USB that can give up to the max.10 khz setting. Manual
ECSS operation is EXCELLENT with the 1 hz tuning steps and
display. The included 0.5 PPM TCXO helps in a big way here as
well. Just as with the NRD-545 there are 3 bandwidth presets that
the user can define. A huge plus is the 7600 has 3 roofing
filters that can be selected (3, 6 and 15 khz) as well as "Sharp
and Soft" shape factor on SSB bandwidths (sadly this does
not work with the AM filters).
But as you can read on my JRC NRD-545 page ,the JRC
suffers from weird sounds that exist within it's DSP and
associated circuit's under certain band conditions. The Icom does
not suffer from this problem , except with Manual ECSS, see green
block below.
Have to stress again , Icom includes a nice 10 khz filter
selection with use on AM signals when signals permit...of course
a HUGE plus for SWL use !!!!
It is not a fast easy job adjusting the bandwidths filters with
the Icom on the fly. With the JRC is just a turn "one knob"
affair. Icom forces you to drop into a menu and push buttons and
turn the main tuning knob, a pain here. Again you do have 3
bandwidths presets as you do with the JRC ,but adjusting to other
filter bandwidths in a split second is where the chore is.
***
Audio Recovery *** : "Is the IC-7600 the best set around for pulling the audio (spoken words) from a very weak signal down in the mud using manual ECSS ?" Not really. With tested elder IC-756 PRO 2 model it was not that good. On the 7600 with it's more advanced DSP receiver scheme and adjustable audio filtering , is improved in standard AM mode. We discovered in later testing that manual ECSS use was near unacceptable, see green block below for more information on this. Also to achieve the same sensitivity level of other sets (i.e.: WJ-8711A / HF1000A, JRC NRD-545 etc.), you MUST have "pre-amp 2" on. This also increases the noise floor greatly, where as the other sets I have tested with DSP like this are much more quiet with the same sensitivity level. Sorry, it's does NOT match the WJ-8711A in audio recovery (but what does) . Even Icom's expensive IC-R9500 receiver does not and yes I have done side by side testing . |
The
7600's AGC is near perfect and works extremely well. The Icom
being MUCH more adjustable over the NRD-545 and can also use it
on AM mode signals (with the JRC of course you cannot). I found
turning OFF the AGC on the IC-7600 can be a huge plus digging out
the weak ones. Usually that is the case too with any receiver
that can do it, however turning off the AGC on the JRC NRD-545 on
a extremely weak signal is a big waste of time and usually makes
it worse. But overall the NRD-545's AGC performs fine for SWL
signals.
Just as it is with the Bandwidth selections, you have "three"
preset variable choices (Fast, Mid and Slow), except on FM where
you only have one. On SSB I use the Defaults, on AM it's near the
defaults too but on FAST I use : 0.3 (or OFF depending on my mood).
IC-756 PRO 2 had excessive audio distortion even in the SSB modes no
matter where I set the AGC values at. With the 7600 it does not
matter, even adjusting the bandwidth filter shape dosen't give
any nasty excessive distortion. MUCH improved !!
Near Excellent Audio Quality / Recovery With Low
Distortion / No Hiss At All / Line Out Level OK / "Beep"
Appears At Line Output /Separate Bass -Treble Audio Tone Controls
for EACH Mode / No Voice Synthesizer on Record Output
Overall audio quality will of course depend what
external speaker is used, and as with most if not all HF
receivers / transceivers, the IC-7600 really MUST have a GOOD
external one......no exceptions. The internal speaker is very
poor !! We use a old "Realistic Minimus 77" (or the
smaller Minimus 7 or the newer Centrios 7 clone) 2 way speaker
and with the added tweeter makes for an added boost in audio
recovery (I know some will cringe on this, but it's a huge plus
for broadcast station and even for amateur use).
Now here is where the IC-7600 blows away all previous models in
this series and a huge plus. Located in the menus (very easily
adjusted) are RX (receive) "Tone adjustments". You have
a separate Bass and Treble for EACH MODE (SSB / AM / FM). Also a
separate High Pass and Low Pass adjustment.
Of course this will totally depend on what speaker is being used
for what settings are to be used, but for my "Realistic
Minimus 77" Speaker :
SSB : Bass +5, Treble : +3
AM and FM : Bass +5 , Treble : +2.
Too sharp sounding if I go any higher here with true SSB mode
signals on Treble, however with manual ECSS for the best audio
recovery the MAX of +5 in Treble works excellent (decrease the
Bass in this case of course for added audio recovery). Yes, it
works excellent and gives the IC-7600 a huge boost for overall
SWL "Broadcast " use.
Some may ask if the general audio
recovery is as good as the WJ-8711A ?? Well NO
it does not. But it's
very
good to excellent provided the tone controls are adjusted proper
to the mode and signal , and to your speaker being used that will
indeed vary this. As compared to the JRC NRD-545, I can easily
adjust the IC-7600's audio sharpness and audio recovery to win
the race in most cases . However the NRD-545's noise floor is
much lower for the same given signal, so it's a trade off.
Another reason why the 7600 sort of wins here is the NRD-545's
semi-sour AGC (even in the SSB modes). Even if we turn down the
545's SSB "AGC T" down to min (0.04), it was still is a
lower showing in comparison .
The overall "audio output" is much more punchy as
compared to the JRC. It does not exhibit the "running out of
volume control" problem that badly plagues the NRD-545. Very
good news is that we have no hiss at all either at the speaker or
line output. Totally clean and sharper audio (dependent on tone
settings) which are huge pluses.
To connect a external recording device into the IC-7600 YOU have
to make, an 8 pin DIN audio record cable into the ACC 1 socket (signal
at pin 5 , indent pointed at the BOTTOM) to tap the fixed audio
"Line Output". Good news is it's at the proper level.
The Icom IC-R9000 was anemic and struggled to give a correct
audio line level.
IMPORTANT NOTE : Just as with the DSP "Tone" control in
the NRD-545, the Bass and Treble adjustments also effect the IC-7600's
"Line Output". Excellent , however it lacks lower bass
so sounds a bit cut off on the lower end of the audio spectrum.
Unlike the old PRO 2 model, the keyboard "Beep" does
NOT appear at "line" audio output. So if you have a
recording going, any button press will not show up, so a plus
here. The downside is that the Voice Synthesizer output does not
show up on the line output. So if you wish to voice stamp the
"frequency voice" on the recording, you are out of luck.
Yes, included as stock out of the box is the Voice Synthesizer.
This was an option with the PRO, PRO 2 and PRO 3 sets. As usual
it can be set for English or Japanese language. One can also have
the voice synthesizer work when you push a mode button (gives the
mode only here of course), but this needs to be toggled on in the
menu's , the default is off. However we found the output level to
be a too low even set at max volume level (also adjustable in the
menu's) .
1 hz Tuning AND Display with a .5 ppm TCXO installed as
Standard
Here is something where JRC never got it right. The JRC NRD-545,
Icom IC-746PRO, IC-756 PRO and PRO II and IC-7600 all have excellent 1 hz tuning.
But most importantly the IC-7600 (and IC-746PRO) "Display the 1 hz tuning"
as well !!! This is a big plus for tuning in "DX" AM
broadcasting stations using manual ECSS in USB or LSB modes (Update:
Oops not so fast here see green block below for important info on this
we discovered on our test sample).
The Icom IC-7600 has unusually consistent frequency accuracy
across it's entire tuning range needed (right gown to the 1hz
digit). The 2 samples of the IC-R9000 were not as good here. The
PRO II's display was off about 50 hz (high) right out of the box.
Good news is that the Icom has an adjustment in the 7600 menu's
to tweak this if required (mine was DEAD ON out of the box) This
is even a better idea than the "adjustment hole"
trimmer on the side with the PRO series sets (rear panel on the IC-746PRO). The R-9000 also had
this, so another good Icom trait passed down to years.
Icom includes (just as it did on the other PRO transceivers) a 0.5
PPM TCXO time base crystal oscillator as standard. With the
JRC NRD-545
this was a $ 100.00 option.
Major "Bug-A-Boo"
: NOISY Internal Fan That Runs FULL TIME (after warmup at normal/warm
room temperature) / LCD Dust Issue
Even being on for a couple of hours and only in receive
mode, we find the IC-7600 to run on the "luke warm"
side of the fence . This is an improvement over the PRO 2 which
ran hot in just receive more so on the underneath on the left
side and also left of the DC power plug. As many know the
internal AC power supply in the IC-R9000 ran so hot as to burn
your fingers if you were touch the rear power supply heat sink (not
kidding) .
However, Icom did the
fan operation right in the PRO and PRO II (PRO III ?). With
the huge heat sink area, and thermostatically controlled fan, our
sample NEVER came on with just receive use.
With the dual DSP system and other improvements in the IC-7600,
sadly after a warm up period and ONLY IN RECEIVE MODE (say 20~30
mins or so depending on room temperature), the NOISY single speed
internal fan switches on and stays on in a normal/warm room.
Noisy fan's that run in a set (or power supply) in only
receive mode at ANY TIME (that has not been put in TX on
cold start) is totally unacceptable to me. This is getting to be
more rare these days. Sorry Icom.........but you blew it on this
one !!
This is of course a very subjective
topic, but this could very well be a total "deal breaker"
for anyone who is sensitive to ANY fan noise (and only in receive
mode) !! I guess one could get used to it (or perhaps not) ?? The
IC-7600 draws around 3 AMPS of current at 13.8 volts in RECEIVE.
But so did the IC-756 PRO and PRO 2.
UPDATE : If the room temperature is on the cool side , the
fan operation may cycle on an off . Also if one operates the
transceiver on 12.0 volts (not 13.8), this will give cooler
operation and depending on room temperature, the fan may cycle on
and off instead of running all the time. However this will give
for a lower "Max" RF power ouput of course (around 90
watts or so as tested).
With all of this air being passed
through the cabinet (and with the fan and VENTS being right up near the
front bezel), reports of samples with disconcerting dust in between the
front LCD bezel screen and the actual LCD screen have appeared (source:
IC-7600 Yahoo Groups).
This would take disassembly of the entire front panel bezel to get at
and clean out. Icom got a bit smarter with the newer IC-7300 in this
area as the intake vents are a bit further back from the front panel
and the fan being rear mounted.
But not to say it completely cures this bug ?? Also the fan in the
IC-7300 runs MUCH less as the cabinet is cooler (even with 100% receive
duty).
Receiver Sensitivity / No Weird DSP Gremlins or Other
Noises...
The IC-7600 is a very sensitive set with lots of receiving power.
Just as sensitive as the JRC NRD-545. The DSP makes no weird
noises so far like the JRC NRD-545 emits (UPDATE: Well not so
fast, see green block below). Lets hope it does not suffer from
the ICOM failure traits that my 2 IC-R9000's had down the road....as
explained more below. However to achieve equal sensitivity the
"Pre Amp 2" MUST be used. This also adds more
background noise over the JRC for the same sensitivity (but this
is normal for Icom's receiver scheme these days).
Inside
the 7600 we
have TWO DSP IC's.
One for the receiver operations and
another for the spectrum scope. The IC-746PRO, IC-756 PRO and PRO II only contained
one DSP chip.
Manual
ECSS had Serious Issue on OUR IC-7600 Sample / Limited SSB Bandwidths
for Manual ECSS Use [NOTE : FIRMWARE 1.11] |
Something
of course this ICOM still lacks but the JRC NRD-545 has and works
excellent , is a "Automatic" ECSS (Exalted Carrier Selectable Sideband)
circuit. You can also call this just "Synchronous Detection". Two
issues are improved using this method receiving a AM mode signal, but
can vary on performance depending on the circuit. First is that the
general fading distortion can be reduced or even eliminated on a AM
signal. Second is that depending what sideband is used can reduce of eliminate interference while still using a wide filter (if the set will allow this). Using the one further away from the offending station. The JRC NRD-545 has a ECSS that automatically locks this circuit in and allows for even use of the max. filter bandwidth (10 KHz). Of course on the Icom we have no such critter. But using "Manual ECSS" , that is selecting USB or LSB on a AM mode signal and zero beating it does work . However we do not have rosy news here after later testing on this mode of tuning with OUR test sample (firmware 1.11). Using manual ECSS (either sideband), with OUR test sample we were hearing intermittent nasty "pops and ticks", which makes for near unacceptable findings in this SWL DX mode. Mind you this will NOT be a deal breaker for Amateur or general SWL use. We tested an early Icom IC-R9500 super set (NOTE : early firmware) and that set also failed in the manual ECSS mode as well (in fact it was really bad) . Adjustments of AGC, decay rates, tone control etc, etc.....made no difference in our findings here. In testing two other friends IC-7600 samples, we were unable to duplicate this bug , however this was with only very limited testing. So it could be a sample variation or other issue here (unknown) ?? Better news is we have a excellent 1 hz tuning and display with rock solid stability (after short warm up). The real stinker here is the limited maximum SSB bandwidth is only 3.6 khz. You can use the "Twin PBT" to additionally tune out the interference along with actually narrowing the bandwidth to help even in very ruff conditions. Just too bad it's not what it could have been here . Most stations will be on frequency, right down to the 1 hz digit. But some are not, so you will have to select the 1 hz tuning step and fine tune it. But you can do it. |
Front
End "Bandwidth" Preselection / Good Dynamic Range
The IC-7600 has an excellent front end stage of passband filters.
Also spurious signal rejection is also superb. So perhaps for a
few little small very minor gremlins that creep up, if this set
is hearing a signal......more than likely it's really there (except
Long Wave).
A problem that the IC-R9000 had tuning in the SW part of
the spectrum was with dynamic range. It would overload fairly bad
at night in the 41 and 49 meter broadcast bands on a good antenna.
Gee, not good what was a $8000 + receiver. The IC-7600 fairs much
better here, but is still not perfect. This is more true with
preamp 2 on . To be fair, I have not had a problem in receiving
any broadcast stations with overloading....none, but at very
strong local HF ham signal I was (only blocks away with a
bit of power as well). But this is really a super test being
pushed here, so the dynamic range is actually very good .
No Attenuation on MW Band / Poor LW (and below) Sensitivity and
Rejection
Many already know from the older PRO series and other
Icom transceivers....the pre-amps do not operate with signals
below 1600 khz (MW : medium wave standard AM Broadcast). Good
news with the IC-7600 is that NO added attenuation on the MW band
is used anymore. Also Pre Amp 1 and Pre Amp 2 BOTH fully operate.
Downside is Long Wave (and below) the sensitivity is not good ,
and is MW rejection is very poor (loaded with MW stations mixed
in). The JRC NRD-545 blows the ICOM into the next planet in this
area.
"Dual Watch" Receive
Here is a feature that might be of use for many,
provided your signals don't go too far apart from each other. We
have a function called "Dual Watch" and this can also
be found on other Icom sets.
As long as you are able to use the same mode and within the same
'"front end" filter range (and say within a couple of
Mhz or so from each other), yes you can listen to 2 frequencies
at the same time. The "Bal" control did take me awhile
getting used to.
Digital Noise Reduction / Notch Filter /
Excellent Noise Blanker
The digital noise reduction feature (NR button) works much better
on than on the PRO II and the (joke) NR button on the JRC NRD-545.
The "in the tube" sound is totally gone the plauged the
IC-756 PRO II. As it usually is with NR , one cannot go too far.
Again is much more useful over JRC NRD-545 circuit that sounds
like all "in a tube" and no signal.
Auto notch auto mode does an excellent job as does the manual one.
They work very well indeed and are most useful and deep. I say
Icom improved here as well.
Excellent "Noise Blanker" performance (at least at our
location and local noise). Fully adjustable too. One of the best
we have ever used in fact.
Only 100 memories, Accessing a Bit of a Pain / Band
Stacking Memories / Notepad Memories
For many 100 memories will be just fine and will not be a problem.
Actually having a smaller amount will make them more useful and
less confusing. Especially when used in the Ham radio realm what
it was really made for. But for SWL use it could be a issue. I
find 100 to be OK considering the lack of a EASY way to access
them.
Yes, accessing the memories is a bit of a pain the rump. Unlike with the IC-746PRO, there is
no "spin wheel" for zipping through them. Instead you
are forced to use the up down arrows on the keypad, or direct
entry (yep, have to hit an extra button as well), even the
buttons on the mic will allow you to surf the memory channels. I
guess this works OK, but it would have been nice for a dedicated
spin wheel encoder knob. They missed this one again !!
You can view a chunk of the memory channels on the LCD and add a
10 character alpha to each memory. Another trait to the R9000
again. I like the way the list is laid out and displayed. But
unlike the memory layout, you still cannot copy and paste which I
kind of miss. Not a biggie here however.
With the front USB port one can make use of a computer keyboard
and enter the alpha tags with more speed and ease.
If you are tuning around the Ham bands, the Band Stacking
Memories will store your last 3 entered entries. This is most
useful and as I do the Ham thing too , but for even SWL use it's
a nice plus.
But even more useful are the "Notepad Memories". You
can store 5 or 10 (user defined) of your most used or hunting for
in the DX world, and these are very easily accessed. Great idea
here.
Internal Digital Audio Recorder, Useless : Too Short Of
Time (30 sec max) / Connection to PC via USB Port
The Icom IC-756 PRO II featured a Digital Audio Recorder which
allowed recording of the off air signal up to 15 seconds (in 4
chunks), or your voice onto the air for up to 90 seconds
total. Well with the IC-7600 the receive record time was
increased to 30 seconds (whopee) in 20 channels for 209 seconds
total.
As for any use for SWL signals, this is still near totally
useless. You can also continually record in a 15 second loop.
Then can playback the last 15 seconds buy just hitting the button
(in case you missed a word or 2). Count on connecting another
device for any broadcast recording (like the "standalone"
Sangean DAR-101 digital recorder) via it's audio line output
jack.
Why Icom still did not allow for longer recording time (like with
the IC-R9500) is beyond me. They blew it AGAIN here !!!
Audio quality from this recorder while being OK for most ham
applications , does degrade a bit however (done A-B testing here
on this).
Another huge plus to the IC-7600 is it has a USB computer port on
the rear panel (connection to a Windows OS computer). After
loading the correct drivers BEFORE you plug it in 3
versions
depending if your computer OS is WIndows XP, WIndows 7, Windows 8
etc). Here
any audio received is also fed over USB to the
computer. So with any PC audio record program you can record "off
air" this way as well.
Good Transmit Audio
Quality Too
As I had made a comment at the top of this report, I will not be
covering the Ham Transmit side of this radio in any detail . But
with the tests I have made at time of writing it was very good
and clean with 3 different transmit bandwidths available. No
excessive relay's clicking when the set is put into transmit. The
7600 has a nice LARGE RED LED transmit indicator , a nice touch.
The mic EQ settings work very well indeed. The included HM-36
hand mic is a real treat, holds in the hand well and has great
tactile feedback. However this Chinese mic will need modification
before any real use (do your own internet searches). We used the Chinese made Icom SM-30 desk
mic with the IC-7600 is worked excellent right out of the box .
Of course the internal antenna tuner should NEVER be used in a
receive only situation (always to be left OFF).
I find the Icom IC-7600 to be a better
receiver for SWL use over the even older IC-756 PRO II / III models. It
has many
functions that no other set manufacture has ever begin to touch.
It does it's DSP business with no weird strange noises or burps (expect
for manual ECSS) which can overtake the JRC NRD-545 superset at
times. Icom made many improvements including MUCH improved audio
quality, AM bandwidths that are now adjustable and the larger LCD
display with LED backlighting.
Downsides are you will have to find a nice hefty 23 Amp 13.8 volt
power supply to get this one to work (if you use it for transmit
as well). A non-switching one too if you want to stay away from
RF noise. Better add the cost of a good external speaker if you
don't already have one around . Run it at 12.0 volts for a tad
cooler operation (with about 10 watts less RF output).
The MAJOR bugs for ME with the IC-7600 is the
excessive internal fan noise (and just being in receive too), excessive
receiver current draw, poor manual ECSS as covered in the green
block above (however this could be a sample
variation ??) and fair band scope with too much noise floor "grass" .
But for many these will not be deal breakers , yes
these are very subjective topics and your view may vary.
The build quality is not in the same league when compared to the
JRC products in my view. It's not poor either...but when one really
compares.....JRC was usually (but not always) on the top for
quality of construction and parts used. But of course they are
long gone manufacturing transceivers or even receivers now and
were always more expensive too. JRC's NRD-545 can
suffer from the dreaded trimmer capacitor issues in the VCO section (so
that is not great news with a unknown sample on the used market).
Icom has manufactured SDR transceiver models after the
IC-7600 and these perform to much higher standing (such
as the IC-7300..my review here).
If at reasonable price, a used IC-7600 would still make for a good
value for "Amateur Radio" use (again is not such a great choice for SWL
use in our view with the firmware version tested) .
Dave N9EWO
© N9EWO, all rights reserved
ver 7.0
DISCONTINUED PRODUCT
I
will NOT be held responsible for any info that is listed here |
*** Icom IC-7600 Service Note : USB Port and Transmit Failure Issues with the IC-7600 *** |
There
has been quite a discussion around the internet in regards to failures
with the IC-7600 USB port and also total transmit failures . In all
cases and situations it appears to have been user inflicted, however
many think it's a flaw with the transceiver especially with
"electrostatic discharge" (ESD) damage . I will agree that modern day
gear is a bit more sensitive to ESD via the antenna (and local ESD
too), and in my view the owner MUST TOTALLY DISCONNECT the antenna physically off the transceiver when
not in use (and I do in all seasons). Of course don't even think of
using the set with any bad weather in the area. If you think adding the
best grounding system , ten 8 foot ground rods, static / lightning
arrestors and even using a grounded antenna switch will prevent any ESD damage 100% to a high-tech modern day amateur transceiver...........THINK AGAIN !!! Via the IC-7600 Yahoo Group : Gilles Deschars F1AGR had a USB port failure with his IC-7600 that I'm going to pass along as I feel it's extremely important in regards to the USB port failure. His IC-7600 USB port failed him twice in three months. First time Icom replaced one IC . Second time they had to change the whole main board. As he said that was a very expensive failure ! It took him a bit of time to find the origin of this issue (but he did). NOTE : He did not comment if the Icom transceiver was powered via a switching type power supply ?? - His IC-7600 was connected to a ASUS laptop via the USB port. - The laptop was powered via 220V/18V SWITCHING power supply . This power supply primary did not have a mains ground connection. Laptop USB ground was same than secondary power supply 0V (negative pole). - After disconnecting the IC-7600 from laptop, He measured 100V between transceiver ground and laptop USB ground. But nearly no current between the two. The origin of this issue was a low current leak between primary and secondary of his laptop power supply. Icom did confirm such ground potential difference was destructive to the IC-7600 USB port. So this is one very important item worth checking BEFORE you connect up your IC-7600 to the computer. ANOTHER IC FAILURE (DEAD OUTPUT) : The small IC that likes to blow on the IC-7600 is IC201 located on the RF Unit . It is a BGA616 Broadband MMIC amplifier. The output of this IC amplifier is fed to the PA unit. So if it fails, you will get no transmit output at all (DEAD). Some owners have blown this one out more than once. Not sure if the above (ESD or Hot USB grounds) might have a play in the IC destruction or if it's other unknown issues causing it ?? |
I
will NOT be held responsible for any info that is listed here |
*** Icom IC-7600 Service Note : Receive and Transmit Both Go Dead !!! *** |
|
Again from information via the IC-7600 Yahoo Group (Eric K2CB)
(however we have included additional more detailed information on this
here) : From user reports, it appears that another common failure that
can occur in time with the Icom
IC-7600 transceiver is a bad connection of the small "DC DC Unit" , which is plugged into
the MAIN BOARD. Even more so
if being used in a smoky , dusty or humid area. This failure may
include : Receive and Transmit
becoming totally DEAD (TX no output all modes). However note
that the multi function meter indications may continue to work BUT are
all wrong including : Showing RF output / ALC full swing / SWR 2.5 / Id
over 25 Amps etc etc. No RF output and current is really only drawing
as in normal receive mode. A possible simple repair to attempt (but it may not be valid in your case) : Remove the bottom cover. In the corner section as indicated in the photos below, you will see the small “DC DC Unit”. This is a small fully shielded metal cased board assembly plugged into the MAIN Board (with it’s bottom of it’s PC board facing up from MAIN board). Remove the two Phillips screws that hold this “DC DC Unit” onto the main unit board / plug. Carefully unplug the unit (just lifts up). Re seat it (and if desired beforehand clean the plug and socket if it can be done PROPERLY and be sure to let fully dry before reseating) and then replace the screws. IF you are skilled enough , it might be worth a try before sending it off to repair. Maybe changing out the CR2032 clock battery might not be a bad idea while it's open (it's in a socket) . Dave N9EWO © N9EWO, all rights reserved ver 2.0 Has your Icom IC-7600
"Receiver and Transmitter" gone both totally DEAD !
|