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).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)
: 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-756 PRO II and IC-756 PRO Transceivers and Icom IC-R9000 Receiver models have been used/tested for comparisons in this report.
Review on the Icom IC-7600 DSP HF / 50 MHz Transceiver (for SWL
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-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-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.
With ICOM's IC-R9000 beast long gone from the marketplace , the IC-7600 is the only way to get a "NEW" HF receiver with a "Good" spectrum display of this type at a price one can even to begin to afford (certainly not the super expensive IC-R9500 for most folks) . Many if not most used R-9000's that are around these days have excessive burn on the CRT displays and other problems from heat stress (they ran extremely HOT) so one has to be very careful purchasing on the used market . 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 !!
PRO, 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 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 (made in China), 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 .
Included updated OPC-1457 DC Power Cable : New version with new style fuse holders .
Our IC-7600 test sample included the "new" version of the OPC-1457 DC power cable (as indicated in a single sheet insert with the manual). You can tell which version just by looking at holders color. This updated cables fuse holder are now BLACK and have a rounded shape and tapers slightly towards the tip . The old ones are WHITE and square caps.
Reason why Icom made this change was reports with the old white style fuse holders, the radio could shut down then turn back on again in Transmit mode . Fuse connections becoming oxidized over time and added resistance and with high current in transmit mode for the voltage drop and cutting out. The RF power output also can drop down to even as low as 50 watts until the fuse and or fuse holder issue are corrected . Sadly reports indicate that this change did little to fix the problem (cleaning is required once in awhile to keep this issue at bay with either holder).
Also noticed with this new version of the cable are the addition of 2 additional parts that are heat shrinked onto the cable , see photo below.
Icom made changes to the OPC-1457 DC cable as shown above. The fuse holders were changed along with 2 added "unknowns" (Adam VA7OJ says EMC filters perhaps ?) in heat shrink tubing. This change was made due to RF "Transmit" power dropping off (or radio totally cutting out) due to oxidized-dirty fuse holder connections. The fuse holders on this new improved cable fit MUCH tighter. However reports indicate that this change did little to fix the problem (cleaning is required once in awhile to keep this issue at bay with either holder). (N9EWO photo left)
Observations / Electronic Meter / Spectrum Scope Just OK / Rubber Feet On
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 the PRO 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) ??
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.
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 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 .
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
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).
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 PRO and PRO II and IC-7600 all have excellent 1 hz tuning. But most importantly the 7600 "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. 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
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 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|
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 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.
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. 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 (see modification information located on the bottom of this page). 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).
"Icom-itus"......lets hope not !!!
The Icom IC-R9000 receiver can suffer from the nasty trimmer capacitor failure problem (I use the term "Icom - itus") that plagues many Icom sets engineered in the era (such as the IC-745 / IC-751 / IC-271 / IC-275 / IC-970 etc). Lets hope the IC-7600 will not suffer from this bug or others down the road ??
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) .
© N9EWO, all rights reserved
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
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.
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
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) .
© N9EWO, all rights reserved
Has your Icom IC-7600 "Receiver and Transmitter" gone both totally DEAD !
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