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Icom IC-756 PRO III
side by side with the Drake R8B

By John Plimmer

The first thing to look at is why would one who is a DX listener only, want to buy a transceiver? Consider the price of receivers today and what's available:

Icom IC-R756 PRO III
Icom IC-756 PRO III (above) and Dreake R8B
Drake R8B

Winradio G313i for US$1,000
The Drake R8B costs US$1,500
The AOR 7030+3 is around $2,120 with the noise blanker and notch upgrade.
The Japan Radio NRD-545 is $1,800
Ten Tec RX-340 at $3,950
Icom IC-756 PRO III for $3,000

The 756 has 32 bit DSP technology and a 24 bit processor against the oppositions 16 bit technology. It also has a spectrum display that otherwise only the Winradio has. I am not going into the detailed technical descriptions of the above radio's as this has been widely published in magazines, handbooks and on the web, but there is general criticism of the 16 bit receivers inability to handle large signal environments and their lack of capacity in close up operation at the IP3 5 Khz spacing.

The 756 does not suffer from these close in signal handling problems, so therefore it represents good value for money for the performance and technology it offers.

Sound

The Drake is renowned for its excellent audio when played through an external good quality speaker and provides a nice mellow sound that you can listen to for hours, whether that be listening to BBC orchestral's or static ridden DX on MW and Tropical Bands.

Earlier Icom's on the other hand were well known for poor audio sound delivery, but this is where the 756 breaks with the Icom tradition, as the sound is excellent with broad spectrum audio. I would describe the sound as "clearer, crisper, tighter and fuller" than the Drake, whilst not being in the least unpleasant to listen to for hours on end. A highly commendable effort by the Icom engineers (an additional outboard speaker is required of course). I ran both sets through my Icom SP-20 speaker that allowed direct comparison.

The Drake has a tone control, whereas the Icom does not have one (not an important issue for me).

On the 756, moving from AM wide to a narrow SSB setting, and/or enabling the NR noise reduction function seriously attenuates the audio output, necessitating an adjustment to the volume control. This does not occur on the Drake and I find it quite irritating on the Icom, continuously having to manipulate the volume control up and down.

Ergonomics

Larry Magne in his Passport review of the Drake R8B says "the only .... receiver tested that gets everything right", and so it is. Everything comes easily to hand and everything the DXer want's is there. But shame Drake! that awful cheap plastic tuning knob is inexcusable in a radio costing $1,500.

The Icom is roughly the same size as the Drake, but a large portion of the fascia is occupied by the large colour LCD display. This makes the numerous functions available necessarily quite small and cramped. The keypad is too small and sits awkwardly right above the lovely large tuning wheel that can easily be knocked off your frequency. The use of the 756 requires quite a long familiarisation and learning curve with the manual on your lap to get to know all the numerous functions and the many variables you may introduce into the operating setup.

Perhaps the most used control is an inner and outer knob control labelled "Twin PBT" passband tuning. It is used for narrowing the set filter in small steps, but when rotated together acts to shift the passband to the upper or lower sideband. This is inconvenient and I would like to have seen a separate knob, as in the Drake, for passband offset only.

A nice touch for boosting your ego is that you can enter your name or callsign permanently into the LCD screen to remind you what a great guy you are for purchasing such a high quality radio.

Filters

Filter offsetHere the 756 comes into its own with its extremely tight filters and the large number of settings you may set and the way you can customise the defaults to your own requirements. I will not go into the technicalities of these filters as they are discussed in great detail in Icom's own Technical Report and also here.

The immediate observation is that they are much tighter and sharper than the Drakes. A "sharp" setting of 2.5 Khz on the Icom proves even tighter than the standard Drake 2.3 Khz filter. On SSB you can set only two filter width's on the Drake, vis 2.3 and 1.8 Khz, whereas on the Icom you can start at a 3.6 Khz setting and then set them to any value down to 250 Hz. This you can do by selecting three default settings to speed up finding the width that is most suitable for you. From the factory the defaults come set in SSB mode for 3.0, 2.4 and 1.8 Khz wide, but you can set these three defaults to any figure you like within the range 600 Hz to 3.6 Khz. I have set mine at 2.5. 2.0 and 1.2 Khz width. You can then narrow a default even further in 100 Hz steps. Very flexible and very effective.

AM mode is less flexible and doesn't offer infinite narrowing of the filters on the 756. The three set defaults for AM are 9.0, 6.0 and 3.0 Khz wide. The 3.0 Khz filter is too narrow for most usage, but becomes useable when the passband is offset to the upper or lower limit. The Drake has 6.0, 4.0 and 2.3 Khz width and 2.3 is useable by rotating the passband offset to obtain the "sweet spot".

If you are a CW NDB beacon DXer, you will find the 756's filters sensational as they run infinitely variable from only 50 Hz up to 1.2 Khz (or higher). A characteristic of a lot of CW filters and add on's is that as the filter gets narrowed the sound starts to "whistle" and "rings", as if it is tunnelling at you. This is not the case with this Icom and you can comfortably set the filter width down to 50 Hz when you locate that really faint beacon. The Drake only has a 500 Hz CW filter width.

In SSB and CW mode the filters width can be narrowed as mentioned, but using the Twin PBT controls it is possible to do this independently on the upper and lower side of the passband non-symmetrically. This is very useful. You cannot adjust the filters on the Drake.

A further useful feature on the 756 is that the filter width you have manipulated is always shown on the display, and if you get "lost" you merely press "PBT clear" to get you back to the default setting. In addition you can call up on the LCD screen a full diagrammatic of the current filter and its width and offset settings.

Two shapes of filter can be set: "soft" for a pleasanter sound, and "sharp" for a clearer DX sound. In practise I use the sharp setting exclusively.

In operation the filters on the 756 seem to have deeper skirts than the Drake and thus consistently render more marginal signals readable than the Drake does.

Passband offset

On the Drake you have one knob to manipulate this - it is uncalibrated and suffers from the fact that it "floats". However constant use allows you to quickly find the "sweet spot" you are looking for.

The 756 on the other hand is much more sophisticated in that the offset is calibrated and is even diagrammatically shown on the filter screen if you call that up. However, it takes a bit of a knack to manipulate the two "Twin PBT" rotary controls simultaneously. I would have preferred the Drakes single knob for that function.

VFO's

4 VFOsThe Drake has two VFO's, only one of which can be seen at a time. Whereas the 756 effectively has four, as it has two VFO's plus two memories active at any one time. The nice thing about the large Icom LCD screen is that the contents of the two VFO's and two active memories can be seen as you DX along = useful. As the memories are fully tuneable you effectively have four VFO's, a very useful feature when the band is open and you are trying for as many ID's as possible. If you manipulate a memory in the Drake it immediately reverts to one of the VFO's, so you still only have two VFO's on the Drake.

Tuning around

The Drake's tuning wheel is a little slow, but by various settings and manipulations it is possible to move quickly from place to place, although you often have to revert to entering a new frequency into the keypad. You can quickly tune the MW split band by leaving a 9 Khz tuning step in the AM MW mode and a 5 Khz step in the SSB mode.

The 756 is a little different. It responds to the tuning wheel much quicker, so moving very rapidly around the band is quite easy. For a MW DX run you would have to set the 9.0 Khz step in AM mode and then a 10.0 Khz step in the SSB mode. If you move to the Tropical Band you would have to reset the tuning step in both modes to a 5.0 Khz step, which is a little cumbersome.

The Drake can be set to automatically revert to a 5.0 Khz tuning step in the Tropical Band, so no additional step resetting is necessary, and when you tune down to the MW band, the Drake automatically reverts to the default 9 or 10 Khz setting = convenient..

The Drake tunes to a minimum of 10 Hz - the Icom tunes to 1 Hz when specially set. The Icom also has a RIT function that operates at a 1 Hz tuning rate.

Display

LCD Spectrum display

The "piece de resistance" of the 756 PRO series must surely be the LCD screen and the frequency spectrum display. If you have not experienced this, then it is something very worthwhile to look forward to. Seeing the stations around your chosen station and their relative strengths is very useful. Finding weak stations in between powerful ones becomes an easy matter. Watching a thunderstorm create havoc on the band is also interesting if futile, as there is still not much you can do with the very heavy static generated by a lightning storm. The bottom screen can be dropped and the top VFO information displayed larger and in more detail.

NR noise reduction

On the Drake the notch filter, being quite broad, does a good job of getting rid of a lot of the white noise associated with DXing. On the 756 though, we have a very effective digital DSP noise reduction. The level and intensity of this can be adjusted by turning a rotary knob. It is very effective at removing all sorts of noise and static on a band and actually enhances the audibility without muffling or distorting the recovered audio sound too much. Annoyingly though it attenuates the audio output a lot and requires you to turn the volume control upwards. That's fine, but you must remember when you have your earphones on to turn the volume down before switching it off, otherwise your ears are going to be blasted with a high volume level.

NB noise blanker

I never found the older Icom NB's very good and they also used to distort the audio. The 756 is quite good though and is nearly as good as the superb Drake NB. The major difference is that whilst both eliminate ignition type pulse noise, the Drake's NB also eliminates some lightning static which the Icom's doesn't do. The Icom's NR feature does that more effectively than the Drake though. Neither of these radio's NB's distort the audio.

Notch

The Drake has an effective notch that is quite broad and easy to tune - it is manual in operation and can therefore only attack one het tone at a time. The notch on the 756 is superb though, as in it's "auto" form it will kill up to three tones at a time and do this on the fly. It also has a manual setting that will kill one single tone, but it is very critical and therefore more difficult to use (others find it easy and useful to use!).

Memories

Memory displayI have never been a big fan of too many memories, and the possible computer control of both these radio's allows for unlimited memories anyway. The R8B has a massive 1000 memories against the 756's 100, more than adequate in my experience though. Both allow for alpha numeric labelling of the memories.

In the Drake you can only see one memory at a time, so unless you arrange these intelligently it becomes quite difficult to see what you have in the memory bank. On the Icom, you can call up on the LCD screen the memory bank and display 7 or 13 memories at a time, which you can then scroll through. Makes memory management and finding something in the memory quite easy.

If you want to manipulate a memory in the Drake, it reverts to the VFO, thus loosing whatever you had in that VFO. On the Icom though, you can manipulate the memory without it going to the VFO unless you instruct it to = handy.

Synchronous detection

If you want to listen for hours to the BBC promenade concerts or music on AM, then the Drakes synchronous detector gives a superb fade free sound that you can listen to undistorted pleasantly for hours.

The Icom does not have synchronous detection and it shows. Deep fading and multi path distortion effects most signals, even from the most powerful stations, and this distorts the audio unless there is a very good sync detector controlling matters. Unfortunately the Icom's audio output of AM and shortwave stations is seriously marred by the lack of a sync detector and the resultant sound can become irritating after a while as the audio keeps distorting and breaking up as the fading/multipath takes place (playing around with the AGC settings may improve this a bit). But you wouldn't buy a 756 PRO III just for listening to the Beeb!

Other comments

The preamp on the 756 is very good and introduces virtually no noise whereas the R8B's preamp introduces a lot of hiss. The advantage of the 756 is very apparent above 15 Mhz.

The Drake has a single 10 dB attenuator whilst the Icom has a three stage attenuator down to minus 18 dB.

The AGC rates on the Drake are very well chosen: off, fast and slow. The Icom has an AGC that is infinitely variable from off, very fast and variable through to very slow.

CW NDB beacon DXing

I have described above how the CW filter width on the Icom can be adjusted all the way down to as little as 50 Hz without ringing or whistling. There are other useful features as well. PBT passband offset to find that sweet spot of the signal, pitch control to enhance the audio tone and CW reverse mode for when you are trying to avoid that unwanted adjacent channel beacon that is interfering with your desired signal. The RIT function is also useful when critically tuning a beacon on a filter width as narrow as 50 Hz. You can also turn the AGC off if you need to and choose a very slow quarter of normal tuning rate..

The 756 runs rings around the Drake as far as CW NDB DXing is concerned.

MW mediumwave mod

As it comes from the factory the LF and MW band has been attenuated to 13 uV sensitivity. My dealer reversed this and enabled full sensitivity and assured me that the guarantee was still good. This involved only a minor mod. The 756 is now slightly more sensitive than the Drake in "normal" mode, but the preamp cannot be activated, whereas on the Drake it can be (others have enabled the preamp 1 on MW on the earlier 756 PRO's).

Unfortunately I am completely non technical and was not present in the workshop when the Icom techie in Johannesburg (1,200 km's away) did the mod. However my friend Guy Atkins supplied me with pictures and a schematic diagram from mods he did and originally worked out by Dallas Lankford for the 756 PRO.

The Joburg techie said he had no problem and booked time of one and a half hours workshop time for this mod including a lot of time for disabling the transmit section.

He marked the 756 PRO III's schematic diagram in case the mod ever has to be reversed. All I can see he marked is bridging R801 to R803 and removing C802 to the earth connection. These parts can be found on the reverse side of page 4 of the schematic diagram, at the top and about a third of the way in. He said it was simple, but when I queried this with him later, he conceded that an amateur solderer without special lab equipment might find it challenging. He said that sort of thing was his everyday work and was easy for him.

Side by side with the Drake R8B the 756 seems, if anything, slightly more sensitive.

You can see the tremendous MW results I get by looking at the South African DXpedition pages at http://www.dxing.info/dxpeditions/ so I am quite satisfied that the MW sensitivity is where it should be and that everything is working properly.

Performance comparison

I tested the radio's on the same RF Systems DX 1 Pro antenna which has twin matched outlets through an Icom SP-20 speaker that allowed instant comparisons.
- 81.5% of stations were better to much better on the Icom 756 PRO III. That is, clearly more readable.
- 7.5% of stations were better and more audible and clearer on the Drake R8B.
- 11% of stations were the same on both radio's

One of the questions hanging over digital radio receivers is their ability to receive a weak signal only 5 Khz apart or less from a powerhouse. I tried this on several frequencies, the most notable being Deutsche Welle on 11,945 which was putting out a massive S9+60 signal. There was a much weaker station almost hidden in the skirts of DW barely showing on the spectrum display on 11,950. The Drake could barely render the weaker signal readable, whereas the 756 did a superb job and rendered the audio quite readable.

I tried many stations from the LF CW beacon area right up through to the top end of the HF band.

On CW NDB beacon chasing the 756 was head and shoulders above the Drake due to its superb narrow filters.

On MW and Tropical Bands the 756 was again better due to its sharper filters and outstanding NR noise reduction circuit.

Higher up the HF band the 756 gets progressively better due to its excellent preamplifiers, whereas the Drakes preamp introduces a lot of hiss that obscures the readability.

Minor matters

The Icom comes poorly packaged - a reputable dealer will repackage it in a stouter box for shipment.

The Icom draws over 3 amps of power and thus runs quite hot even in receive mode only. If you run it on batteries on a DXpedition, you are going to need big ones.

Cool things

The spectrum display on the 756, the sharp and tight filters and the ability to set them anyway you like, and the very effective NR noise reduction.

The R8B's superb synchronous detector for hours long comfortable listening to shortwave programming. Great ergonomics - everything is where you want it with one touch of a button.

CONCLUSION

So, the bottom line is this: is the Icom 756 PRO III worth double the price of the Drake R8B?

I think the answer lies like this: If you are a casual listener, like to get some rare stations now and again but also like to listen to good music and programming on AM and shortwave, then the R8B will probably do very well for you and you may not find the 756 much better for your purposes. The R8B is a venerable receiver that has achieved awesome results in the hands of serious DXer's over the years.

But if you are a serious hardcore DXer and have owned all the current offering of receivers, you will find the latest technology in the 756 very useful and with a performance that is top line. I think you will be quite happy with this set even though you have outlayed $3,000 on it. It offers a better chance of IDing that very faint station deep in the heavy static. The tools available to do this are impressive.

The law of "diminishing returns" applies. Although the 756 PRO III represents the very latest in cutting edge digital technology, the improvements over the Drake R8B are incremental, but nonetheless significant.

Postscript

If you were thinking of buying a Drake R8B or similarly priced RX, you might like to consider a good pre-owned model from eBay. The older 756Pro and 756ProII models should be looked at, as they are very similar in operation to the 756 PRO III. In the USA, the 756ProII is currently selling new for about $2100 new, and used for $1600. A 756 PRO II at $1600 would be an outstanding DX radio.

An excellent full size professional photo of the Icom 756 PRO III can be found at the Icom UK website.

Postscript II, 18 months later (May 8, 2006)

It is now eighteen months since I acquired the Icom 756 PRO III and it has been on four serious DXpeditions and is in continuous use at the home QTH. Things have moved on since my original report and sadly the Drake R8B is now off the market and no longer manufactured. Pity, as it is a great receiver and I still miss the wonderful easy to use ergonomics and solid all round performance.

However I am more than pleased with the 756 and if I shot from the hip and say what impresses me most, it is:
# The sharp filters and nice clear cut sound in SSB mode
# The flexible filter options and passband offset
# The awesome notch - the auto setting zaps out hets one time, but the manual notch is really marvellous for getting rid of all sorts of electronic interference that the auto setting doesn't do.
# I can't really say that I am getting any more exotic DX logged than on the old Drake, but I can say that I am getting much better quality recordings of exotic far off 13,000 kilometer/8,000 mile distant MW signals than ever before.
# My chasing of NDB CW beacons has gone up exponentially as the Icom's CW performance is really very impressive with the wide range of filter options and enhancement controls available. On the Drake my furthest beacon was only 1,700 kilometers away, but with the Icom I have now got beacons as far away as 6,000 kilometers/3,750 miles.

What I don't like and that irritates me:
# The cramped controls, some of the most used ones like the VFO swap/change, and VFO to Mem are so small that you need to operate the radio in bright light in order not to push the wrong button, and then you often do anyway.
# Also the fact that the NR noise reduction reduces the audio output and also the recording level on line out. This means on a weak signal you do not have enough line out oomph to make a decent recording.
# The NR is good on strong signals and does a great job of eliminating static, but when the going gets tough and the signals are weak, the NR muffles the audio intelligibility to such an extent that you can no longer get a clear ID and have to switch it off.
# During the day when DX is not present, I listen to my favourite AM BCB and BBC stations, but I miss the Drakes lovely sound and rock solid synchronous detector. On the Icom I have to listen in SSB to avoid fading, but the sound, despite eighteen months of fiddling and trying to optimise it, is not very good.

Overall though, I am very happy with the Icom, it is a very satisfying radio to DX with, and it has proved to be a substantial upgrade on my old Drake.

(published on DXing.info on January 2, 2005,
second postscript added on May 8, 2006,
and one more paragraph added on July 4, 2007)

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