Drake R8 question
 

Pete KE9OA wrote:

I may be picking up one of these things tomorrow. Looking at the input
bandpass filter schematic, I notice a T type of attenuator that consists of
two 270 ohm series resistors, with a 330 ohm shunt resistor on the MW filter
section.
Am I dreaming, or did Drake really dumb down the design with a full time
attenuator on the MW band? If this is the case, it looks like I have yet
another project.

Pete

I don't see that attenuator on the MW (0.5-1.5-Mhz) bandpass filter for
the R8'B'. The MW bandpass circuit on the 'B' looks like all the other
bands but with different component values of course.

Drake R8 question
 

That sounds good.............the service manual I have is for the R8E, so
they may have installed an attenuator on that model. I will give Drake a
call this morning.

Pete

"Drakefan" wrote in message
news:Fluxj.7931$xg6.6122@trnddc07...
Pete KE9OA wrote:

I may be picking up one of these things tomorrow. Looking at the input
bandpass filter schematic, I notice a T type of attenuator that consists
of two 270 ohm series resistors, with a 330 ohm shunt resistor on the MW
filter section.
Am I dreaming, or did Drake really dumb down the design with a full time
attenuator on the MW band? If this is the case, it looks like I have yet
another project.

Pete

I don't see that attenuator on the MW (0.5-1.5-Mhz) bandpass filter for
the R8'B'. The MW bandpass circuit on the 'B' looks like all the other
bands but with different component values of course.

Drake R8 question
 

Pete KE9OA wrote:

That sounds good.............the service manual I have is for the R8E, so
they may have installed an attenuator on that model. I will give Drake a
call this morning.

I get the same S meter readings on the R8, R8A and R8B. The attenuator can be
kicked in on all three, difference being is that the pre-amp can be used in the
A & B but not on the R8.

Drake R8 question
 

Drakefan wrote:
Pete KE9OA wrote:

I may be picking up one of these things tomorrow. Looking at the input
bandpass filter schematic, I notice a T type of attenuator that
consists of two 270 ohm series resistors, with a 330 ohm shunt
resistor on the MW filter section.
Am I dreaming, or did Drake really dumb down the design with a full
time attenuator on the MW band? If this is the case, it looks like I
have yet another project.

Pete

I don't see that attenuator on the MW (0.5-1.5-Mhz) bandpass filter for
the R8'B'. The MW bandpass circuit on the 'B' looks like all the other
bands but with different component values of course.

Different first mixer?

Drake R8 question
 

No, it is using the same 1st mixer. In my service manual for the R8E, right
after the input switching diode for the MW range, I see the attenuator. I
just talked to Bill Frost, over at Drake, and he tells me that all of the
front ends are the same. If this is the case, it shouldn't be too hard to
remove it. They may have pulled a tricky one, the JRC did with the MW range
on the
NRD-515.
On another note, I have built the first engineering prototype of the new
Palstar active loop antenna. There was a bit of a delay receiving the
ferrite rod stock, but that should be coming in, in the next few days or
so.
I still need a few PCB footprint files.........after this, I will be able to
do the board layout. It shouldn't take more than a few hours to do.

Pete

"dave" wrote in message
...
Drakefan wrote:
Pete KE9OA wrote:

I may be picking up one of these things tomorrow. Looking at the input
bandpass filter schematic, I notice a T type of attenuator that consists
of two 270 ohm series resistors, with a 330 ohm shunt resistor on the MW
filter section.
Am I dreaming, or did Drake really dumb down the design with a full time
attenuator on the MW band? If this is the case, it looks like I have yet
another project.

Pete

I don't see that attenuator on the MW (0.5-1.5-Mhz) bandpass filter for
the R8'B'. The MW bandpass circuit on the 'B' looks like all the other
bands but with different component values of course.

Different first mixer?

Drake R8 question
 

Thanks Steve............I appreciate that. Years ago, when I was living in
Cedar Rapids, there was a fellow named Steve in Michigan that had some sort
of intermod problem with a Sony 6800W. Were you that person, or was it
another Steve?

Pete

"dxAce" wrote in message
...


Pete KE9OA wrote:

That sounds good.............the service manual I have is for the R8E, so
they may have installed an attenuator on that model. I will give Drake a
call this morning.

I get the same S meter readings on the R8, R8A and R8B. The attenuator can
be
kicked in on all three, difference being is that the pre-amp can be used
in the
A & B but not on the R8.

Drake R8 question
 

Pete KE9OA wrote:

Thanks Steve............I appreciate that. Years ago, when I was living in
Cedar Rapids, there was a fellow named Steve in Michigan that had some sort
of intermod problem with a Sony 6800W. Were you that person, or was it
another Steve?

Not me Pete, I've never had a 6800W.

Drake R8 question
 

Thanks Steve,

I am going to take a look at that R8 in a little while and see how it works.
My friend is also bring over an R7 S/N 3400 range, with a PLL unlock
problem. Just what I always wanted to work on...........another one!

Pete

"dxAce" wrote in message
...


Pete KE9OA wrote:

Thanks Steve............I appreciate that. Years ago, when I was living
in
Cedar Rapids, there was a fellow named Steve in Michigan that had some
sort
of intermod problem with a Sony 6800W. Were you that person, or was it
another Steve?

Not me Pete, I've never had a 6800W.

Drake R8 question
 

U bet you............I've got it apart right
now......................cleaning the contacts on the regulator board got
the low end of the low band VCO working....................the high band VCO
only works up at MHz. I am thinking, that with the high S/N, it looks like
the owner of this radio sold the R7A face plate to somebody and installed an
R7 faceplate on this radio before he moved it out.
I played a little bit with the R8...........now I see why everybody likes it
so much. I think I will modify it so the preamp works on all ranges, that
is, after I remove that pesky MW attenuator. Nice receivers.

Pete

"dxAce" wrote in message
...


Pete KE9OA wrote:

Thanks Steve,

I am going to take a look at that R8 in a little while and see how it
works.
My friend is also bring over an R7 S/N 3400 range, with a PLL unlock
problem. Just what I always wanted to work on...........another one!

Keep those R7's running.

Drake R8 question
 

Pete KE9OA wrote:

U bet you............I've got it apart right
now......................cleaning the contacts on the regulator board got
the low end of the low band VCO working....................the high band VCO
only works up at MHz. I am thinking, that with the high S/N, it looks like
the owner of this radio sold the R7A face plate to somebody and installed an
R7 faceplate on this radio before he moved it out.
I played a little bit with the R8...........now I see why everybody likes it
so much. I think I will modify it so the preamp works on all ranges, that
is, after I remove that pesky MW attenuator. Nice receivers.

I just saw a message on the Drake reflector wondering about a possible change
due to the serial number. Thought it must be an R7A vs. an R7.

Name Dan, by any chance?