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Old September 27th 05, 02:53 AM
 
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Default Icom 756 Pro II filter settings

Hello,

I recently purchased an Icom 756 Pro II for both ham and especially for
use as a serious SWL DX radio. I am looking for other Pro II users who
also do serious shortwave Dxing with this rig.
My question is what settings do you find as most optimal on Filter 1,2
and 3 for DXing?
Any other tips that improve SWL DXing on this rig would be greatly
appreciated.

73

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Old September 27th 05, 06:54 AM
John Plimmer
 
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I've been DXing with mine about a year now and the settings I favour in SSB
mode a
Fil1 - 2.9 khz with +300 offset
Fil2 - 2.5 khz with +150 offset
Fil 3 - 2.0 khz with - 100 offset
That's for DXing AM signals in the SSB mode

Of course in AM mode the filters are fixed at 3/6/9 khz,
but you can swing the passband offset in the 3 khz setting quite a lot to
good effect.

In the lower tropical bands I would not use more than preamp 1 if any.

The NR noise reduction should be used judiciously - toggle it on/off to see
which gives the most audible signal.

Conditions are great this morning @ 0600z
11,820 New Zealand is coming in nicely - haven't heard them in over a year
NZ is always a very difficult catch here as the path lies direct over the
Antarctic auroral belt.
Also AFN Pearl Harbour nice and strong on 6,350
--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx

wrote in message
oups.com...
Hello,

I recently purchased an Icom 756 Pro II for both ham and especially for
use as a serious SWL DX radio. I am looking for other Pro II users who
also do serious shortwave Dxing with this rig.
My question is what settings do you find as most optimal on Filter 1,2
and 3 for DXing?
Any other tips that improve SWL DXing on this rig would be greatly
appreciated.

73



  #3   Report Post  
Old September 27th 05, 11:53 PM
R.F. Collins
 
Posts: n/a
Default Icom 756 Pro II filter settings

In AM I almost always use the 6.0 kHz setting. 9.0 kHz sounds great
but on the crowded SW bands its usually not an option.
For SSB SWL DXing and amateur use I have the 3 positions set at 3.0,
2.4, and 2.0 kHz.

One external piece of equipment that is great to have with this rig is
an antenna tuner. The combination of matching the antenna to the
frequency you are listening to and adjustment of the DSP NR to remove
background noise really makes listening more enjoyable and also helps
to pull out the weak DX stations.

I can't wait to get a Pro III. They have to put them on sale
eventually.

Jim

On 26 Sep 2005 18:53:38 -0700, wrote:

Hello,

I recently purchased an Icom 756 Pro II for both ham and especially for
use as a serious SWL DX radio. I am looking for other Pro II users who
also do serious shortwave Dxing with this rig.
My question is what settings do you find as most optimal on Filter 1,2
and 3 for DXing?
Any other tips that improve SWL DXing on this rig would be greatly
appreciated.

73


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Old September 28th 05, 02:46 AM
 
Posts: n/a
Default Icom 756 Pro II filter settings

Hi John,

Thanks for the quick and very informative response. I am going to try
your settings to see if I get improvement over my settings. I had my
Pro set as follows:
Filter 1 2.2 with -125 offset
Filter 2 2.5 with 0 offset
Filter 3 3.5 with +125 offset

I think that perhaps the 3.5 may be to wide and I am curious to see if
the 2.9 will be more effective for my DXing.

On AM the filter i seem to utilize the most for general listening is
Filter 3/3.0 Of course, for very weak DX the SSB filters on AM are
usually the most effective.

Also, I noted you have the BCB mod on your rig. Do you know anyone in
the states that does this mod. I am not very technically inclined.
Anything else you find helpful on the Pro for BCB dxing?
It is currently 0200 Z .. and Iran is coming in weakly on 9.495. This
should prove useful for trying your filtering recommendations.
Thanks again,
David W5CTK

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Old September 28th 05, 03:29 AM
 
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Default Icom 756 Pro II filter settings

Hello Jim,
Thanks for the comments, your filter settings are very similiar to the
ones that John posted. You guys must be onto something!
I will also at some point have to try adding an outboard tuner as you
suggested.
Like yourself, I would love to upgrade at some point to the Pro III as
well.
73, David



  #6   Report Post  
Old September 28th 05, 03:21 PM
John Plimmer
 
Posts: n/a
Default Icom 756 Pro II filter settings

reply for David and Justin.
As it comes from the factory, the Icom 756 Pro series has the MW band, that
is under 1600 Khz, attenuated.
The mod that the local South African Icom agent did for me to restore full
sensitivity below 1600 Khz on the MW band was based on diagrams supplied by
friends in the States.
I did not do the mod to enable the preamps below 1600 Khz, as I found the
normal sensitivity more than adequate, a fact proved on my last three
DXpeditions where the furthest and faintest of stations were logged (1 Kw at
8,000 miles away).
Also, I use my Kiwa MW Loop and that can give a massive boost to very faint
signals.

The mods are not for the casual solderer, but best left to a professional
with lab quality soldering equipment and desoldering gear, plus a lot of
experience.

If you want more info on these mods, please e-mail me privately and I will
pass on your query to my friend in the States.
If you are a serious MW BCB DXer, these mods are essential and work
perfectly.
--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx

wrote in message
oups.com...
Hi John,

Thanks for the quick and very informative response. I am going to try
your settings to see if I get improvement over my settings. I had my
Pro set as follows:
Filter 1 2.2 with -125 offset
Filter 2 2.5 with 0 offset
Filter 3 3.5 with +125 offset

I think that perhaps the 3.5 may be to wide and I am curious to see if
the 2.9 will be more effective for my DXing.

On AM the filter i seem to utilize the most for general listening is
Filter 3/3.0 Of course, for very weak DX the SSB filters on AM are
usually the most effective.

Also, I noted you have the BCB mod on your rig. Do you know anyone in
the states that does this mod. I am not very technically inclined.
Anything else you find helpful on the Pro for BCB dxing?
It is currently 0200 Z .. and Iran is coming in weakly on 9.495. This
should prove useful for trying your filtering recommendations.
Thanks again,
David W5CTK



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Old September 28th 05, 04:37 PM
 
Posts: n/a
Default Icom 756 Pro II filter settings

Icom 756.That's one of them little teentsy weentsy little bitty hand
held radios,isn't it?
cuhulin

  #8   Report Post  
Old September 29th 05, 05:34 AM
John Plimmer
 
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Default Icom 756 Pro II filter settings

Reference to the official Icom 756 Pro III spec sheet will show you that the
MW band below 1.8 Mhz is attenuated by 11 dB, a significant suppression that
will prevent you hearing that really faint distant DX.

The mod to remove this suppression is to be found on:
Sheet 4 reverse side (back) of the "schematic diagram" at the top just left
of the middle of the diagram.
the mod is
bridge R801 to R803
disable/disconnect C802

I am told that the schematics for the Pro/Pro II may not be the same as for
the Pro III

The mods for the 756 Pro have been described in great detail by Dallas
Lankford and a Google search will reveal them.
Look for:
IC-746Pro Impressions & Mods

Dallas Lankford, 6/13/04
--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx


"Bart Bailey" wrote in message
...
In posted on Wed, 28 Sep
2005 16:21:30 +0200, John Plimmer wrote: Begin

As it comes from the factory, the Icom 756 Pro series has the MW band,
that
is under 1600 Khz, attenuated.


I think all bands outside of the one you're tuned to are attenuated,
that's why the dual VFOs are best used on frequencies within the same
range, but I haven't noticed the MW region to be any more attenuated
than any other. I use either a tunable loop or a 42 foot vertical
depending on target and conditions, and get good results.

The mod that the local South African Icom agent did for me to restore full
sensitivity below 1600 Khz on the MW band was based on diagrams supplied
by
friends in the States.


I have the full set of schematics that came with it,
but it's no trivial task to spot a band specific feature.
Maybe you could post the chip involved and I could focus my search?

I did not do the mod to enable the preamps below 1600 Khz, as I found the
normal sensitivity more than adequate,


That's the mod I was referring too, if such exists, besides, you don't
have to enable them if you don't want to. I actually use the attenuator
on local stations if I want to get a better view of their signal in the
spectrum scope.

side note - I enjoy trying to dig weaker distant stations out from
underneath strong locals, for example Here in San Diego KFMB 760 is a
monster, but just next door (at night) is a station on 770. It's
programming isn't particularly interesting so I haven't listened long
enough to confirm the call (I think it's KKOB Albuquerque, NM ).
Another weak adjacent target is 810 KGO SF which is next to 800 XESPN
Tijuana. I use upper sideband on KGO 810 and can actually employ the
wide 3.6kc bandwidth filter to get reasonable quality audio. Back before
XESPN 800 became an affiliate for the entertainment sports network, it
was an over-modulated XEMM ("Musica Mariachi") that no amount of
filtration could overcome.

--

Bart



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Old September 29th 05, 06:13 PM
Mark Zenier
 
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Default Icom 756 Pro II filter settings

In article ,
Bart Bailey wrote:
side note - I enjoy trying to dig weaker distant stations out from
underneath strong locals, for example Here in San Diego KFMB 760 is a
monster, but just next door (at night) is a station on 770. It's
programming isn't particularly interesting so I haven't listened long
enough to confirm the call (I think it's KKOB Albuquerque, NM ).


Could be KTTH Seattle, "The Truth". Rush Limbaugh & the like.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)
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