[ICOM] 756 vs 756Pro2

Thu Sep 9 13:51:45 EDT 2004

Gentlemen,

I had the opportunity to compare my 756 vs a pro2 side by side recently and
thought some of you might be interested in my observations.  I made the
following notes when I did the comparison. All in all, I like the pro2
better and eventually plan on getting a Pro3 to replace the old 756.

My notes on the 756 vs the 756pro2:

Receiver notes:
The 756 seems to be worse than the pro2 in some areas and better in others
based on the ARRL expanded test reports.  The expanded reports show that the
In-Band Receiver IMD of the 756 is not as good as the pro2.  The Swept
Dynamic Range Graphs also appears to show worse performance for the 756 than
the pro2 when you get closer to the receive frequency.

IMD Dynamic Range (based on ARRL test reports) - The pro2's IMD Dynamic
range is about 10 dB better  than the 756 at 5KHz spacing but about 10dB
worse at 20KHz spacing.  I could not detect a difference during operation.
The bands, however,  were not very crowded.  Rough calculations show that I
would need at least a 10dB over S9 signal to even begin to see any effects
on the pro2. The 756, however, would get IMD with only an S9 signal.

Blocking Dynamic Range (based on ARRL test reports) - First, note that IMD
Dynamic range causes problems long before BDR is a problem. The pro2's
dynamic blocking range is about 10 dB worse than 756 at 20KHz spacing.  I
could not, however, detect a difference during operation. The bands,
however,  were not very crowded.  Rough calculations show that I would need
at least a 60dB over S9 signal to begin to see any effects on the pro2. The
756 would require about a 70dB over S9 signal. NOTE that the BDR is about
the same for the ProII and 756 with only 5KHz spacing.

Sensitivity (observation)- With no preamps on the 756 I could hear very weak
CW QSOs when the pro2 could not hear them. I had to turn on a preamp on the
pro2 to equal the 756 without the preamp.  This is consistent with the ARRL
test results that shows about a 3dB difference in sensitivity between the
756 and pro2 with no preamps on.  Sensitivity seemed to be equal with the
preamps enabled on both radios.

AGC on 756 is much faster than on pro2.  "Slow" on the 756 is about the same
as "fast" on the pro2.

PBT better on Pro2,  but the pro2 operates in opposite direction from 756.
The 756 is backwards from what I would expect.

NR may be a little better on the Pro2

Noise reduction on pro2 works on AM.  Does not seem to work on AM on the 756

Noise Blanker is adjustable. Don't really have much need for the noise
blanker here.

The pro2's adjustable filter width and shape is really nice,  250Hz sounds
good, but 50Hz has clicks well outside filter BW

Transmitter notes:
The pro2's BW adjustments on compression are nice, plus the compression is
metered now

The higher mic gain on pro2 allows use of more microphones.

Other notes:
The pro2 has a prettier display with more options

The pro2's front panel is easier to read because of higher contrast colors

The pro2's bandscope sensitivity is about 20 dB higher

The pro2 has a digital voice recorder. I may use this, not sure

The pro2's voice monitor functions better

Any comments are appreciated.

John DeRuiter, WM7A
http://members.cox.net/wm7a/

-----Original Message-----
From: icom-bounces at mailman.qth.net
[mailto:icom-bounces at mailman.qth.net]On Behalf Of John Geiger
Sent: Thursday, September 09, 2004 9:02 AM
To: ICOM Reflector
Subject: Re: [ICOM] QST Prod Rev Expanded Reports: a proposal

Of course the ARRL is in the business of pleasing
advertisers.  Go look at the review for the FT897.  It
has terrible numbers.  The text of the article talks
about its outstanding performance, and how the numbers
are almost as good as those for the FT1000MP MKV, when
they aren't even close.

It is interesting that the numbers for the 756PRO do
not seem all that outstanding.  THey are not as good
as the receive numbers for the 756 original.

73s John NE0P

--- awallacejr at sbcglobal.net wrote:

> Interesting opinions but to suggest that the ARRL
> tests are "nearly
> worthless" is a little over the top. Sherwood is in
> the business of selling
> filters so he is hardly unbiased. The folks in this
> group who really know
> what they are doing think the 756 Pro ll is one of
> the very best radios ever
> offered to hams.
>
> Andy  K5VM
>
>
> ----- Original Message -----
> From: "David J. Ring, Jr." <n1ea at arrl.net>
> To: "ICOM Reflector" <icom at mailman.qth.net>
> Sent: Thursday, September 09, 2004 1:33 AM
> Subject: Re: [ICOM] QST Prod Rev Expanded Reports: a
> proposal
>
>
> > Oh, I did find some ratings and comparisons to the
> ICOM IC-756PRO2 (and
> > other) receivers.
> >
> > I would pretty much agree with this list, although
> I can mention some
> other
> > receivers that I would guess gave the R390 (one of
> the top receivers) a go
> > for the money (or glory!).
> >
> > I really was surprised at how well the ICOM IC-775
> did - I've never had
> the
> > pleasure of using one of these, but from this
> data, I am going to search
> one
> > out.
> >
> > Take a look - it is great reading.  At least the
> "stock" Drake R4C is no
> > match for the ICOM IC-756PRO2, but the R4C with
> very narrow roofing
> filters
> > work very well under crowded band conditions.
> >
> > Really fun reading - I wish there was more of this
> stuff.
> >
> >
>
http://www.sherweng.com/Dayton_2004/Dynamic_Range_Data.pdf
> >
> > 73
> >
> > DR
> >
> > ----- Original Message -----
> > From: "Jan C. Robbins" <swanman at cfu.net>
> >
> > Just please for heaven's sake pay attention to
> what Rob Sherwood has
> > told you.  At the moment, your reciver measures
> are nearly worthless.
> > Dr. Jan C. Robbins, n0JR
> >
> > ----
> > Your Moderator: Dick Flanagan K7VC,
> icom-owner at mailman.qth.net
> > Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > Icom FAQ: http://www.qsl.net/icom/
>
>
> ----
> Your Moderator: Dick Flanagan K7VC,
> icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
>

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----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
Icom Users Net: Sundays, 1700Z, 14.316 MHz
Icom FAQ: http://www.qsl.net/icom/