[ICOM] IC-775
Michael Sell
k0com at comcast.net
Sat Aug 20 14:12:01 EDT 2005
Looking for 19" rack mount handles for this radio. I saw a picture on line
from Europe that showed them mounted on the unit. Anyone know where I can
get a pair?
73, Michael
KØCOM
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of icom-request at mailman.qth.net
Sent: Saturday, August 20, 2005 11:27 AM
To: icom at mailman.qth.net
Subject: Icom Digest, Vol 2, Issue 372
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Today's Topics:
1. RE: PRO vs PRO2 (Adam Farson)
2. RE: PRO/PRO2 vs. 775DSP (Adam Farson)
3. Re: PRO/PRO2 vs. 775DSP (Hans Remeeus)
4. Re: Modified VHF/UHF rigs (K8CM)
5. 756 Tested (flearl at msn.com)
6. RE: PRO/PRO2 vs. 775DSP (KE5CTY Bob)
7. Re: PRO/PRO2 vs. 775DSP (Crocdonz at aol.com)
8. RE: PRO/PRO2 vs. 775DSP (Adam Farson)
9. Re: PRO/PRO2 vs. 775DSP (Hans Remeeus)
10. Re: 756 Tested (John Geiger)
----------------------------------------------------------------------
Message: 1
Date: Sat, 20 Aug 2005 00:55:39 -0700
From: Adam Farson <farson at shaw.ca>
Subject: RE: [ICOM] PRO vs PRO2
To: 'ICOM Reflector' <icom at mailman.qth.net>
Message-ID: <0ILI00C9FGOO8D at l-daemon>
Content-Type: text/plain; charset=US-ASCII
Hi Dave,
Well - going on my very favourable experience with DSP-based radio
architecture over the past 6 years, I would go for the IC-7000 over the
IC-706 (in any event, once S/N > 2000.) There is a fair degree of
confidence that the IC-7000 will be a big improvement over the IC-706
series.
There are two schools of thought in DSP architecture. One approach is to run
the ADC at a fixed IF, and limit the sampling bandwidth at the analogue
input to the ADC by means of roofing filters following the mixers. The
roofing filter bandwidth is a trade-off between (1) reducing the statistical
likelihood that strong signals outside the DSP-IF bandpass will "ride
through" and overload the ADC, and (2) increased insertion loss, poorer
phase response and degraded temperature stability in the roofing filter
itself. The last is especially true of roofing filters cut for a high 1st IF
(e.g. 64 MHz) as required in a continuous-coverage system.
The roofing filter needs to be placed at the IF output of the first mixer.
Placing costly multi-pole crystal or mechanical filters in the low IF ahead
of the ADC will not improve overall system performance, as a
properly-designed roofing filter after the first mixer will already have
determined the ADC sampling bandwidth - and that is what counts. From then
on, the DSP can emulate all those "sweet-sounding" IF filters if desired.
Rockwell-Collins no longer use Collins filters for selectivity; all their
current HF radio systems are DSP-based.
There is really no need to expend R&D resources "mixing" analogue and DSP
filters in the IF signal path, as the DSP designer can cook up a filter to
do whatever the end-user wants. By manipulating the number of taps (poles),
frequency and phase response, and group delay, the guy writing the DSP code
can emulate anything from a bell-shaped Collins filter to a rectangular
passband, within reason. Doubtless, he will design the filter for optimum
communications effectiveness.
The other approach is to run the ADC at RF, and have it sample the entire HF
range. The disadvantage of this is that the composite power of multiple
strong signals in the sampling bandwidth will eat up all the system headroom
and overload the ADC. (A good AGC, derived from the DSP, can partially
offset this problem.)
http://www.qsl.net/ab4oj/icom/ic756pro_notes.html#rf_if
The DSP designer can also tailor the baseband emerging from the DAC to
"sound" the way the customer wishes, but I suspect that HF radio
communications systems will stick pretty closely to the ITU-R guideline (350
Hz to 2.7 kHz at the -6 dB points). That is what sells vast quantities of
HF-SSB radio gear to all manner of purchasers.
Running the ADC at 400 kHz or so will eliminate one down-conversion in a
radio such as the IC-756Pro series. But then again, the IC-7800
down-converts from 64 MHz to 36 kHz in one step, using an I/Q second mixer.
As I have commented in previous posts, continuous coverage (dictating the
high 1st IF) is not a marketing nicety. It is an RFP requirement for all
military, governmental and commercial HF systems. A radio communications
manufacturer must be a player in these sectors if it desires to make a
profit and survive; we amateurs are co-beneficiaries of this business.
Cheers for now, 73,
Adam VA7OJ/AB4OJ
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of David J. Ring, Jr.
Sent: 20 August 2005 00:02
To: ICOM Reflector
Subject: Re: [ICOM] PRO vs PRO2
Thanks Adam, I hadn't noticed that yet as my material on the 7000 is sparse.
But I would it would be a good competitor for the 706 -
How about you, Adam, if it were EVEN money, would you buy the 706MK2G or the
7000?
An interesting question - I actually wouldn't jump at the 7000 because of
how good the '706 is.
Of course it brings up the question - where is the balance between analog
and digital?
When technology is able to bring DSP i.f. up to the 400 kHz range, it would
be VERY interesting to mix mechanical / crystal filters with DSP "backbone"
of ultimate rejection.
Would the "natural" shape factor of mechanical or crystal filters still
"sound" better then? I like Collins filters - they have a beautiful sound -
but at the bandpass ends, they're obviously not as quiet as DSP - they have
hiss leakage, etc.
But imagine a flat DSP bandpass with brick wall AFTER that Collins filter?
Awesome, I'd think.
73
David N1EA
----- Original Message -----
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Friday, August 19, 2005 9:19 PM
Subject: RE: [ICOM] PRO vs PRO2
Hi Dave,
The DSP in the 7000 is slower than in the 756Pro series or in the
746Pro/7400. The final (DSP) IF is 16 vs. 36 kHz.
What I have seen thus far is that the filter shape factors are not quite as
good; SSB 2.4 kHz is 1.625 vs 1.50.
Cheers for now, 73,
Adam VA7OJ/AB4OJ
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of David J. Ring, Jr.
Sent: 19 August 2005 13:27
To: ICOM Reflector
Subject: Re: [ICOM] PRO vs PRO2
The very sharp 50 Hz filtering is better in the PRO2 than in the PRO.
But there are several reviews around that say the improvements to the PRO2's
dsp chain were mostly incorporated into the IC-746PRO.
I'd go for a 746PRO or I'd wait for the new IC-7000 coming out and go for
that. More bang for the buck.
73
DR
Scanned by WinProxy
http://www.Ositis.com/
------------------------------
Message: 2
Date: Sat, 20 Aug 2005 01:01:46 -0700
From: Adam Farson <farson at shaw.ca>
Subject: RE: [ICOM] PRO/PRO2 vs. 775DSP
To: 'ICOM Reflector' <icom at mailman.qth.net>
Message-ID: <0ILI008FWGYYZC at l-daemon>
Content-Type: text/plain; charset=US-ASCII
Dear Hans,
How about meeting up at Friedrichshafen 2006? We will be able to spend some
time together then.
I am seriously thinking of giving Dayton a rest next year, and attending
Friedrichshafen instead.
My good friend Matt KK5DR now has an IC-7800. He owned an IC-775DSP some
years ago; today, during our weekly 17m sked, he made it very clear that
none of the other radios he has had in his station even comes close to his
7800.
Cheers for now, 73,
Adam VA7OJ/AB4OJ
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Hans Remeeus
Sent: 20 August 2005 00:44
To: ICOM Reflector
Subject: Re: [ICOM] PRO/PRO2 vs. 775DSP
Dear Adam,
Many thanks for your (as always) very enthusiast message! I agree there are
many advantages of the nowadays DSP-technology.
I regret that I don't live in your neighbourhood. I think we can spend many
interesting hours on this subject!
Some day I hope to be able to compare the IC-7800 with the IC-775DSP. It
will be a tough match, HI!
The impact of a linear amplifier (I have the Acom 2000A) indeed is very big.
This is my daily encounterment.
The Chain is as Strong as Its Weakest Link!
73,
Hans Remeeus (PA1HR)
http://www.remeeus.nl
Communication is about people, the rest is technology.
Scanned by WinProxy
http://www.Ositis.com/
------------------------------
Message: 3
Date: Sat, 20 Aug 2005 11:15:33 +0200
From: "Hans Remeeus" <hans at remeeus.nl>
Subject: Re: [ICOM] PRO/PRO2 vs. 775DSP
To: "ICOM Reflector" <icom at mailman.qth.net>
Message-ID: <004601c5a567$ca0f44e0$9700000a at pa1hr>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Dear Adam,
It really would be great to meet eachother in Friedrichshafen 2006!
BTW; I am planning a (first) visit to Dayton next year. Not sure yet.
Thanks for the info about KK5DR his (highly appreciated) opinion. Before I
make such an important decision I have to listen - very carefully and for at
least a couple of hours - to both rigs side-by-side. I did this 15 years ago
to compare the TS-850S and the FT-990.
73, Hans Remeeus (PA1HR)
http://www.remeeus.nl
Communication is about people, the rest is technology.
---- Original Message ----
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Saturday, August 20, 2005 10:01 AM
Subject: RE: [ICOM] PRO/PRO2 vs. 775DSP
> Dear Hans,
>
> How about meeting up at Friedrichshafen 2006? We will be able to
> spend some time together then.
>
> I am seriously thinking of giving Dayton a rest next year, and
> attending Friedrichshafen instead.
>
> My good friend Matt KK5DR now has an IC-7800. He owned an IC-775DSP
> some years ago; today, during our weekly 17m sked, he made it very
> clear that none of the other radios he has had in his station even
> comes close to his 7800.
>
> Cheers for now, 73,
> Adam VA7OJ/AB4OJ
------------------------------
Message: 4
Date: Sat, 20 Aug 2005 10:18:29 -0400
From: K8CM <K8CM at qsl.net>
Subject: Re: [ICOM] Modified VHF/UHF rigs
To: ICOM Reflector <icom at mailman.qth.net>
Message-ID:
<6.0.1.1.2.20050820101315.01f7cec8 at pop-server.cinci.rr.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Probably not ... but, since it can be done, it frequently is. Many of the
older 2M/440 rigs would not receive outside the ham band unless a mod was
made; however, that same mod added the ability to TX outside the ham bands
as well.
Just 'cause a mod has been done doesn't mean that the owner/operator was in
violation.
73 <> Carl
At 11:19 PM 8/19/2005, you wrote:
>Here is a question I have been discussing with another local ham, and one
>that has us puzzled. I would guess that maybe 5% of hams are involved in
>MARS or CAP (that is probably a high estimate). So why is it that 80% of
>the used VHF/UHF rigs and HTs have been modified for wide band
>transmit? Are there really that many freebanders out there?
>
>73s John NE0P
>who just got a modified HT in today
>----
>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/
------------------------------
Message: 5
Date: Sat, 20 Aug 2005 10:27:49 -0500
From: <flearl at msn.com>
Subject: [ICOM] 756 Tested
To: <icom at mailman.qth.net>
Message-ID: <BAY107-DAV130F12A5A065E8BBB2D418D5B40 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
Hello:
Suggest anyone contemplating an Icom 756 look at http://www.w8ji.com
click on receivers and the tests are at the bottom. Make your own
conclusions.
73
Warren N0WF
------------------------------
Message: 6
Date: Sat, 20 Aug 2005 10:56:40 -0500
From: "KE5CTY Bob" <rtnmi at sbcglobal.net>
Subject: RE: [ICOM] PRO/PRO2 vs. 775DSP
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Message-ID: <01db01c5a59f$c87bd930$6401a8c0 at D9FBHB71>
Content-Type: text/plain; charset="US-ASCII"
(QUOTE)
I did this 15 years ago
to compare the TS-850S and the FT-990.
(END QUOTE)
What was your summary conclusion on these two rigs?
Some say the 990 beat it hands down.
73 fer nw,
Bob
KE5CTY (old calls WB5ZQU - WY5L)
10X# 37210, FP#-1141, SMIRK#-5177
http://www.qsl.net/ke5cty/
Code may be taking a back seat for now,
but the pioneering spirit that put the code
there in the first place is out front of it all.
> -----Original Message-----
> From: icom-bounces at mailman.qth.net
> [mailto:icom-bounces at mailman.qth.net] On Behalf Of Hans
Remeeus
> Sent: Saturday, August 20, 2005 4:16 AM
> To: ICOM Reflector
> Subject: Re: [ICOM] PRO/PRO2 vs. 775DSP
>
>
> Dear Adam,
>
> It really would be great to meet eachother in
Friedrichshafen 2006!
>
> BTW; I am planning a (first) visit to Dayton next year.
Not sure yet.
>
> Thanks for the info about KK5DR his (highly appreciated)
> opinion. Before I
> make such an important decision I have to listen - very
> carefully and for at
> least a couple of hours - to both rigs side-by-side. I
did
> this 15 years ago
> to compare the TS-850S and the FT-990.
>
>
> 73, Hans Remeeus (PA1HR)
> http://www.remeeus.nl
> Communication is about people, the rest is technology.
>
>
> ---- Original Message ----
> From: "Adam Farson" <farson at shaw.ca>
> To: "'ICOM Reflector'" <icom at mailman.qth.net>
> Sent: Saturday, August 20, 2005 10:01 AM
> Subject: RE: [ICOM] PRO/PRO2 vs. 775DSP
>
> > Dear Hans,
> >
> > How about meeting up at Friedrichshafen 2006? We will
be
> able to spend
> > some time together then.
> >
> > I am seriously thinking of giving Dayton a rest next
year, and
> > attending Friedrichshafen instead.
> >
> > My good friend Matt KK5DR now has an IC-7800. He owned
an IC-775DSP
> > some years ago; today, during our weekly 17m sked, he
made it very
> > clear that none of the other radios he has had in his
station even
> > comes close to his 7800.
> >
> > Cheers for now, 73,
> > Adam VA7OJ/AB4OJ
>
> ----
> 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/
>
------------------------------
Message: 7
Date: Sat, 20 Aug 2005 12:36:08 EDT
From: Crocdonz at aol.com
Subject: Re: [ICOM] PRO/PRO2 vs. 775DSP
To: icom at mailman.qth.net
Message-ID: <1db.4215305a.3038b5f8 at aol.com>
Content-Type: text/plain; charset="US-ASCII"
now you need to try a 781. IMHO it beats them all!
don-kd9mf
------------------------------
Message: 8
Date: Sat, 20 Aug 2005 09:55:49 -0700
From: Adam Farson <farson at shaw.ca>
Subject: RE: [ICOM] PRO/PRO2 vs. 775DSP
To: 'ICOM Reflector' <icom at mailman.qth.net>
Message-ID: <0ILJ008415OYFS at l-daemon>
Content-Type: text/plain; charset=us-ascii
Hi Don,
Yes, but I sold my IC-781 in 1998.
http://www.qsl.net/ab4oj/icom/756p2_781.html
Cheers for now, 73,
Adam VA7OJ/AB4OJ
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Crocdonz at aol.com
Sent: 20 August 2005 09:36
To: icom at mailman.qth.net
Subject: Re: [ICOM] PRO/PRO2 vs. 775DSP
now you need to try a 781. IMHO it beats them all!
don-kd9mf
Scanned by WinProxy
http://www.Ositis.com/
------------------------------
Message: 9
Date: Sat, 20 Aug 2005 19:08:13 +0200
From: "Hans Remeeus" <hans at remeeus.nl>
Subject: Re: [ICOM] PRO/PRO2 vs. 775DSP
To: "ICOM Reflector" <icom at mailman.qth.net>
Message-ID: <011a01c5a5a9$d218e4b0$9700000a at pa1hr>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hello Bob,
Yes, it was the FT-990 which easily won the match. Receiver performance and
ease of use were the winning items.
I used him almost daily for a period of nine years - as my only rig - and
never regretted it.
73, Hans Remeeus (PA1HR)
http://www.remeeus.nl
Communication is about people, the rest is technology.
---- Original Message ----
From: "KE5CTY Bob" <rtnmi at sbcglobal.net>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Saturday, August 20, 2005 5:56 PM
Subject: RE: [ICOM] PRO/PRO2 vs. 775DSP
> (QUOTE)
> I did this 15 years ago
> to compare the TS-850S and the FT-990.
> (END QUOTE)
>
> What was your summary conclusion on these two rigs?
> Some say the 990 beat it hands down.
>
> 73 fer nw,
> Bob
> KE5CTY (old calls WB5ZQU - WY5L)
> 10X# 37210, FP#-1141, SMIRK#-5177
> http://www.qsl.net/ke5cty/
> Code may be taking a back seat for now,
> but the pioneering spirit that put the code
> there in the first place is out front of it all.
------------------------------
Message: 10
Date: Sat, 20 Aug 2005 17:16:35 -0000
From: "John Geiger" <ne0p at lcisp.com>
Subject: Re: [ICOM] 756 Tested
To: "ICOM Reflector" <icom at mailman.qth.net>
Message-ID: <002601c5a5aa$eb36fd00$3a704143 at lcisp.com>
Content-Type: text/plain; charset="iso-8859-1"
Based on actual on-the-air use, the receiver is not as bad as the figures
indicate. It is certain better than the receiver on the 706MKIIG ( you
would have to look hard to find a receiver worse than a MKIIG) although his
figures put the MKIIG ahead. The 756 is probably not as good as the 775,
but it certain is a very good HF performer.
73s John NE0P
----- Original Message -----
From: <flearl at msn.com>
To: <icom at mailman.qth.net>
Sent: Saturday, August 20, 2005 3:27 PM
Subject: [ICOM] 756 Tested
> Hello:
> Suggest anyone contemplating an Icom 756 look at http://www.w8ji.com
> click on receivers and the tests are at the bottom. Make your own
> conclusions.
> 73
> Warren N0WF
> ----
> 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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