Hello all

I have been searching high and Low for a mod that removes the Medium
Wave band attenuator. If anyone out there knows a site please direct
me and e-mail me direct I would greatly appreciate it.
MIKE

First State

There is a very good reason for that MW attenuator -- better do your
homework before making a mod that an inexperienced tinker has written about.
The folks that designed your receiver knew what they were doing.

See URL: http://www.dxing.com/tnotes/tnote06.pdf
--
The Anon Keyboard
I doubt, therefore I might be


"Mike" wrote in message
m...
Hello all

I have been searching high and Low for a mod that removes the Medium
Wave band attenuator. If anyone out there knows a site please direct
me and e-mail me direct I would greatly appreciate it.
MIKE

First State

Hi Mike,

Despite the dire warnings of the other person who responded to your request,
I've done the MW attenuator removal for an IC-756Pro and it works great to
improve the trans-Pacific MW DX I hunt for. The attenuator is the same in
both the IC-756Pro and the IC-756Pro2, so I'm going to send you files via
email that should help you out.

In fact, I'll be performing this mod on a friend's IC-756Pro2 soon. He's
also a foreign MW DXer who bought the transceiver just for it's excellent
receiver section (like I did).

I need to give credit to Dallas Lankford (an electronics prof. at a college)
who figured out the mod. The file with the schematic was done by Dallas, and
I created the file which shows the component layout. I also have Dallas'
modification for enabling the preamp on mediumwave if you want it (I have
not done this mod, as I already have a high-IP3 Wellbrook preamp inline
after my antenna splitter).

Dallas Lankford is definitely not an inexperienced tinkerer; he's one of the
two most brilliant people in electronics that I know personally; the other
is my good friend Craig Siegenthaler at Kiwa Electronics.

All you need to do for the attenuator mod is to carefully remove one SMD cap
and one SMD resistor, and add a short jumper wire (I used wire-wrap Kynar).
The mod took me less than 1/2 hour to perform. It's supposedly good for 10
or 11 dB gain.

The mod definitely helps the 756Pro series to hear weak MW DX better... mine
is now in a virtual tie for MW sensitivity with my modded R-75.

BTW, I use 450 ft. and 700-ft. Beverage antennas at home, and have found no
adverse effects from the mod, despite a number of S9+60db local transmitters
in the area. I live in a high-RF area near Seattle/Tacoma and the
trans-Pacific (and rarely European) mediumwave stations are still heard
here. The MW attenuator removal mod has helped, not hindered.

I've removed MW attenuators in an IC-R70, an R-75, and now a IC-756Pro. In
all instances my DX reception improved. The foreign MW DX on mediumwave is
often weak, and sensitivity is frequently a major issue. I've DXed these
foreign MW stations for 15 years, and have found this consistently to be the
case. Overloading & images have been rare with these receivers as-modded,
and if they do crop up and/or interfere, it's a simple matter to add
attenuation as needed, reduce the RF gain, or both.

Guy Atkins

Puyallup, WA



"Mike" wrote in message
om...

Hello all



I have been searching high and Low for a mod that removes the Medium

Wave band attenuator. If anyone out there knows a site please direct

me and e-mail me direct I would greatly appreciate it.

MIKE



First State

The "dire warning" was only an attempt to tell the poster -- examine why the
attenuator is there in the first place and make sure the person recommending
the mod knows what they are doing

Then make your choice.

--
The Anon Keyboard
I doubt, therefore I might be



"4nradio" wrote in message
news:KQLqd.485437$D%.205830@attbi_s51...
Hi Mike,

Despite the dire warnings of the other person who responded to your
request, I've done the MW attenuator removal for an IC-756Pro and it works
great to improve the trans-Pacific MW DX I hunt for. The attenuator is the
same in both the IC-756Pro and the IC-756Pro2, so I'm going to send you
files via email that should help you out.

In fact, I'll be performing this mod on a friend's IC-756Pro2 soon. He's
also a foreign MW DXer who bought the transceiver just for it's excellent
receiver section (like I did).

I need to give credit to Dallas Lankford (an electronics prof. at a
college) who figured out the mod. The file with the schematic was done by
Dallas, and I created the file which shows the component layout. I also
have Dallas' modification for enabling the preamp on mediumwave if you
want it (I have not done this mod, as I already have a high-IP3 Wellbrook
preamp inline after my antenna splitter).

Dallas Lankford is definitely not an inexperienced tinkerer; he's one of
the two most brilliant people in electronics that I know personally; the
other is my good friend Craig Siegenthaler at Kiwa Electronics.

All you need to do for the attenuator mod is to carefully remove one SMD
cap and one SMD resistor, and add a short jumper wire (I used wire-wrap
Kynar). The mod took me less than 1/2 hour to perform. It's supposedly
good for 10 or 11 dB gain.

The mod definitely helps the 756Pro series to hear weak MW DX better...
mine is now in a virtual tie for MW sensitivity with my modded R-75.

BTW, I use 450 ft. and 700-ft. Beverage antennas at home, and have found
no adverse effects from the mod, despite a number of S9+60db local
transmitters in the area. I live in a high-RF area near Seattle/Tacoma and
the trans-Pacific (and rarely European) mediumwave stations are still
heard here. The MW attenuator removal mod has helped, not hindered.

I've removed MW attenuators in an IC-R70, an R-75, and now a IC-756Pro. In
all instances my DX reception improved. The foreign MW DX on mediumwave is
often weak, and sensitivity is frequently a major issue. I've DXed these
foreign MW stations for 15 years, and have found this consistently to be
the case. Overloading & images have been rare with these receivers
as-modded, and if they do crop up and/or interfere, it's a simple matter
to add attenuation as needed, reduce the RF gain, or both.

Guy Atkins

Puyallup, WA



"Mike" wrote in message
om...

Hello all



I have been searching high and Low for a mod that removes the Medium

Wave band attenuator. If anyone out there knows a site please direct

me and e-mail me direct I would greatly appreciate it.

MIKE



First State

Afterthought -- I modded a Kenwood to take out the attenuator -- the dynamic
range was apprecably degraded so I put the attenuator back in.

In the second Kenwood -- the mod had provision to switch the attenuator in
or out from the rear panel and most of the time -- the best results were
with the attenuator in.

On the MW band there is so much noise -- person made and atmosperic that the
increased sensitivy does little good\

If you have a beverage antenna -- thats a noise reducer and I'm sure helps
reception as the Beverage antenna is highly directional, responsive to
low-angle signals, has little noise pick-up, and produces excellent signal
to noise ratios.

Your reception may vary

--
The Anon Keyboard
I doubt, therefore I might be



"Keyboard In The Wilderness" wrote in message
news:Y6Mqd.184002$hj.120235@fed1read07...
The "dire warning" was only an attempt to tell the poster -- examine why
the attenuator is there in the first place and make sure the person
recommending the mod knows what they are doing

Then make your choice.

--
The Anon Keyboard
I doubt, therefore I might be



"4nradio" wrote in message
news:KQLqd.485437$D%.205830@attbi_s51...
Hi Mike,

Despite the dire warnings of the other person who responded to your
request, I've done the MW attenuator removal for an IC-756Pro and it
works great to improve the trans-Pacific MW DX I hunt for. The attenuator
is the same in both the IC-756Pro and the IC-756Pro2, so I'm going to
send you files via email that should help you out.

In fact, I'll be performing this mod on a friend's IC-756Pro2 soon. He's
also a foreign MW DXer who bought the transceiver just for it's excellent
receiver section (like I did).

I need to give credit to Dallas Lankford (an electronics prof. at a
college) who figured out the mod. The file with the schematic was done by
Dallas, and I created the file which shows the component layout. I also
have Dallas' modification for enabling the preamp on mediumwave if you
want it (I have not done this mod, as I already have a high-IP3 Wellbrook
preamp inline after my antenna splitter).

Dallas Lankford is definitely not an inexperienced tinkerer; he's one of
the two most brilliant people in electronics that I know personally; the
other is my good friend Craig Siegenthaler at Kiwa Electronics.

All you need to do for the attenuator mod is to carefully remove one SMD
cap and one SMD resistor, and add a short jumper wire (I used wire-wrap
Kynar). The mod took me less than 1/2 hour to perform. It's supposedly
good for 10 or 11 dB gain.

The mod definitely helps the 756Pro series to hear weak MW DX better...
mine is now in a virtual tie for MW sensitivity with my modded R-75.

BTW, I use 450 ft. and 700-ft. Beverage antennas at home, and have found
no adverse effects from the mod, despite a number of S9+60db local
transmitters in the area. I live in a high-RF area near Seattle/Tacoma
and the trans-Pacific (and rarely European) mediumwave stations are still
heard here. The MW attenuator removal mod has helped, not hindered.

I've removed MW attenuators in an IC-R70, an R-75, and now a IC-756Pro.
In all instances my DX reception improved. The foreign MW DX on
mediumwave is often weak, and sensitivity is frequently a major issue.
I've DXed these foreign MW stations for 15 years, and have found this
consistently to be the case. Overloading & images have been rare with
these receivers as-modded, and if they do crop up and/or interfere, it's
a simple matter to add attenuation as needed, reduce the RF gain, or
both.

Guy Atkins

Puyallup, WA



"Mike" wrote in message
om...

Hello all



I have been searching high and Low for a mod that removes the Medium

Wave band attenuator. If anyone out there knows a site please direct

me and e-mail me direct I would greatly appreciate it.

MIKE



First State

That's true about the Beverage antennas. Every one I've used, whether at
home or on DXpeditions, has benefited from a bit of preamplification. At
home I only use the Wellbrook module I have, because of the modest gain
(10-12db) and high IP3 (+43dBm) and high IP2 (+78dBm) it has. I save my
higher gain ARR preamp (18-20dB) for use in rural areas on DXpeditions in
case I need the extra gain (usually I do not... the Wellbrook preamp is
sufficient most of the time).

Here in the Pacific NW we are in an unusual situation regarding noise on the
bands. We have the fewest T-storm days of anywhere in the continental US,
and the natural background noise can be very low in the mid-winter. This is
particularly true at a coastal DXpedition site (with Beverage antennas) just
past sunrise when the noise levels drop even further. (Sunlight has wiped
out the QRM from the east.) In these circumstances, other DXers and I have
found that extra amplification on mediumwave is VERY helpful for logging the
trans-Pacific mediumwave DX. I know this seems counter-intuitive, but
readability of the foreign DX between the 10-kHz domestic channels is really
helped in these situations. Perhaps with a higher gain, noisier antenna the
preamplification would be worthless.

I mentioned the R-70 receiver in my last post; I need to make a correction.
It was not a MW attenuator I removed for that radio, but I enabled the
preamp below 1.6 MHz by the cutting of a logic control wire. The preamp
*did* cause overload problems at my former Seattle QTH, but it was useful on
DXpeditions away from local transmitters and RF.

Guy


"Keyboard In The Wilderness" wrote in message
news:CpMqd.184005$hj.31159@fed1read07...
Afterthought -- I modded a Kenwood to take out the attenuator -- the
dynamic range was apprecably degraded so I put the attenuator back in.

In the second Kenwood -- the mod had provision to switch the attenuator
in or out from the rear panel and most of the time -- the best results
were with the attenuator in.

On the MW band there is so much noise -- person made and atmosperic that
the increased sensitivy does little good\

If you have a beverage antenna -- thats a noise reducer and I'm sure helps
reception as the Beverage antenna is highly directional, responsive to
low-angle signals, has little noise pick-up, and produces excellent signal
to noise ratios.

Your reception may vary

--
The Anon Keyboard
I doubt, therefore I might be



"Keyboard In The Wilderness" wrote in message
news:Y6Mqd.184002$hj.120235@fed1read07...
The "dire warning" was only an attempt to tell the poster -- examine why
the attenuator is there in the first place and make sure the person
recommending the mod knows what they are doing

Then make your choice.

--
The Anon Keyboard
I doubt, therefore I might be



"4nradio" wrote in message
news:KQLqd.485437$D%.205830@attbi_s51...
Hi Mike,

Despite the dire warnings of the other person who responded to your
request, I've done the MW attenuator removal for an IC-756Pro and it
works great to improve the trans-Pacific MW DX I hunt for. The
attenuator is the same in both the IC-756Pro and the IC-756Pro2, so I'm
going to send you files via email that should help you out.

In fact, I'll be performing this mod on a friend's IC-756Pro2 soon. He's
also a foreign MW DXer who bought the transceiver just for it's
excellent receiver section (like I did).

I need to give credit to Dallas Lankford (an electronics prof. at a
college) who figured out the mod. The file with the schematic was done
by Dallas, and I created the file which shows the component layout. I
also have Dallas' modification for enabling the preamp on mediumwave if
you want it (I have not done this mod, as I already have a high-IP3
Wellbrook preamp inline after my antenna splitter).

Dallas Lankford is definitely not an inexperienced tinkerer; he's one of
the two most brilliant people in electronics that I know personally; the
other is my good friend Craig Siegenthaler at Kiwa Electronics.

All you need to do for the attenuator mod is to carefully remove one SMD
cap and one SMD resistor, and add a short jumper wire (I used wire-wrap
Kynar). The mod took me less than 1/2 hour to perform. It's supposedly
good for 10 or 11 dB gain.

The mod definitely helps the 756Pro series to hear weak MW DX better...
mine is now in a virtual tie for MW sensitivity with my modded R-75.

BTW, I use 450 ft. and 700-ft. Beverage antennas at home, and have found
no adverse effects from the mod, despite a number of S9+60db local
transmitters in the area. I live in a high-RF area near Seattle/Tacoma
and the trans-Pacific (and rarely European) mediumwave stations are
still heard here. The MW attenuator removal mod has helped, not
hindered.

I've removed MW attenuators in an IC-R70, an R-75, and now a IC-756Pro.
In all instances my DX reception improved. The foreign MW DX on
mediumwave is often weak, and sensitivity is frequently a major issue.
I've DXed these foreign MW stations for 15 years, and have found this
consistently to be the case. Overloading & images have been rare with
these receivers as-modded, and if they do crop up and/or interfere, it's
a simple matter to add attenuation as needed, reduce the RF gain, or
both.

Guy Atkins

Puyallup, WA



"Mike" wrote in message
om...

Hello all



I have been searching high and Low for a mod that removes the Medium

Wave band attenuator. If anyone out there knows a site please direct

me and e-mail me direct I would greatly appreciate it.

MIKE



First State