7030+ front end
 

For the last couple of weeks I've been testing out a 7030+. It's a very
nice receiver, all decked out with Collins filters. Until earlier
today, I hadn't used it to listen to anything in the 2-3mhz range. But,
largely because of an earlier thread relating to intermod and the
7030+'s front end, I decided to put it through its paces.

To my surprise, there were noticeable images of big broadcast stations
popping up on numerous frequencies. Now mind you, I'm in Brooklyn, NY
and the BCB stations around NYC have to strain even the sturdiest front
end. So, I wasn't all *that* surprised to find these images. However,
it's interesting to note that none of these images are present on the
Drake R8B.

I don't mean this as a criticism of the 7030+, since it's a great
performer with lots of interesting features. I just find this result a
little surprising.

Fortunately, once I put a Kiwa BCB rejection filter in line, the
problem disappeared.

Steve

That's very strange indeed, as the 7030+ has the highest blocking specs of
any hobby receiver and higher than some very expensive professional
receivers.
It should definitely outperform a R8B in blocking out of band high power TX
signals, so I suspect there is something wrong with it.
Maybe whoever installed the Collins filters did not do a proper job and this
is causing the breakthrough's and intermods?
Don't give up on the 7030+ as over time it has proved to be one of the best
RX's available.
Many of the top DXer's in Europe use it and they are near 1000 KW TX's -
they have no problems.
Have it checked out by a professional with the workshop manual.

--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-756 PRO III with MW mods
RX Drake R8B, SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
Hallicrafters SX-100, Eddystone 940
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...
For the last couple of weeks I've been testing out a 7030+. It's a very
nice receiver, all decked out with Collins filters. Until earlier
today, I hadn't used it to listen to anything in the 2-3mhz range. But,
largely because of an earlier thread relating to intermod and the
7030+'s front end, I decided to put it through its paces.

To my surprise, there were noticeable images of big broadcast stations
popping up on numerous frequencies. Now mind you, I'm in Brooklyn, NY
and the BCB stations around NYC have to strain even the sturdiest front
end. So, I wasn't all *that* surprised to find these images. However,
it's interesting to note that none of these images are present on the
Drake R8B.

I don't mean this as a criticism of the 7030+, since it's a great
performer with lots of interesting features. I just find this result a
little surprising.

Fortunately, once I put a Kiwa BCB rejection filter in line, the
problem disappeared.

Steve

These are probably not images reflected by the intermediate frequency but
second and/or third harmonics of the MW stations. Presumably you have ruled
out any cause external to the radio, e.g., the comparison is being made
using the same antenna and with no other device (including the other
receiver) connected at the same time.

Tom

Yes, only a single antenna is being used. I now think something has to
be wrong with the 7030+ because the overload I'm experiencing on it is
actually worse than the overload I experience on my Lowe HF-150--so,
that clinches it. My guess is the SD5400 mixer needs to be replaced,
but that's just a guess. No other aspect of the receiver's functioning
appears compromised. It's as sensitive as ever and an external highpass
filter temporarily improves things.

I can send it off to AOR UK if necessary, though it'll have to wait a
few weeks until my business travel has ended.

If any of you guys have other hypotheses about what the source of this
difficulty is, please let me know. Thanks.

Steve

http://www.aoruk.com/pdf/fet.pdf

The above link should shed some light on your situation..........it looks as
if the SD5400 mixer is damaged. It shouldn't be too hard to replace. I don't
have any of those on hand, or I would send you one of them.

Pete

wrote in message
ups.com...
Yes, only a single antenna is being used. I now think something has to
be wrong with the 7030+ because the overload I'm experiencing on it is
actually worse than the overload I experience on my Lowe HF-150--so,
that clinches it. My guess is the SD5400 mixer needs to be replaced,
but that's just a guess. No other aspect of the receiver's functioning
appears compromised. It's as sensitive as ever and an external highpass
filter temporarily improves things.

I can send it off to AOR UK if necessary, though it'll have to wait a
few weeks until my business travel has ended.

If any of you guys have other hypotheses about what the source of this
difficulty is, please let me know. Thanks.

Steve

http://www.aoruk.com/7030bulletin.htm

This link has all of the service bulletins for the 7030.

Pete

wrote in message
ups.com...
Yes, only a single antenna is being used. I now think something has to
be wrong with the 7030+ because the overload I'm experiencing on it is
actually worse than the overload I experience on my Lowe HF-150--so,
that clinches it. My guess is the SD5400 mixer needs to be replaced,
but that's just a guess. No other aspect of the receiver's functioning
appears compromised. It's as sensitive as ever and an external highpass
filter temporarily improves things.

I can send it off to AOR UK if necessary, though it'll have to wait a
few weeks until my business travel has ended.

If any of you guys have other hypotheses about what the source of this
difficulty is, please let me know. Thanks.

Steve

If you check the front end configuration of these two receivers, you'll see
that the Drake R-8 has a half octave switched preselector filter, and the
AOR7030 has only a low pass filter. That will make a big difference in what
shows up near the broadcast band. When you put the BCB blocking filter in
front of the 7030 that's equivalent to what is already in the Drake. I
expect the 7030 is working up to specs.

John Reed


"John Plimmer" wrote in message
...
That's very strange indeed, as the 7030+ has the highest blocking specs of
any hobby receiver and higher than some very expensive professional
receivers.
It should definitely outperform a R8B in blocking out of band high power
TX
signals, so I suspect there is something wrong with it.
Maybe whoever installed the Collins filters did not do a proper job and
this
is causing the breakthrough's and intermods?
Don't give up on the 7030+ as over time it has proved to be one of the
best
RX's available.
Many of the top DXer's in Europe use it and they are near 1000 KW TX's -
they have no problems.
Have it checked out by a professional with the workshop manual.

--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-756 PRO III with MW mods
RX Drake R8B, SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
Hallicrafters SX-100, Eddystone 940
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...
For the last couple of weeks I've been testing out a 7030+. It's a very
nice receiver, all decked out with Collins filters. Until earlier
today, I hadn't used it to listen to anything in the 2-3mhz range. But,
largely because of an earlier thread relating to intermod and the
7030+'s front end, I decided to put it through its paces.

To my surprise, there were noticeable images of big broadcast stations
popping up on numerous frequencies. Now mind you, I'm in Brooklyn, NY
and the BCB stations around NYC have to strain even the sturdiest front
end. So, I wasn't all *that* surprised to find these images. However,
it's interesting to note that none of these images are present on the
Drake R8B.

I don't mean this as a criticism of the 7030+, since it's a great
performer with lots of interesting features. I just find this result a
little surprising.

Fortunately, once I put a Kiwa BCB rejection filter in line, the
problem disappeared.

Steve

I'd be tempted to agree with you if I hadn't compared the 7030+ with my
HF-150 this morning. The HF-150 was significantly less prone to
overload than the 7030+, and I can't believe it would be if the latter
were performing up to specs. I suspect the SD5400 mixer is damaged,
since that's known to produce this sort of problem. I'm also sort of
hoping it's a damaged SD5400 mixer, since that's a relatively easy
thing to fix.

Steve

"John Plimmer" wrote (in part):

snip
That's very strange indeed, as the 7030+ has the highest blocking specs
of
any hobby receiver and higher than some very expensive professional
receivers.
snip

I had the good fortune to have a 7030+ to play with for a couple of
weeks.
I would sell kidney or other spare body part tonight to buy one.
However I live less then 4 miles from a littlel 1KW MW on 770.
And we a few fairly local power houses at 590 and 630 and 1300.
On the 7030+ I could receive the 770+590 fairly strong the , the
770+630
and and the 770+1300 very strong. In a nearby park about twice as far
from the 770 station as my home, I get no mix products. The 770 is so
strong that it will show up in most receivers even with the antenna
disconnected and replaced with a 50 ohm terminator. By most receivers
I mean R390, R392, R5000, R2000 DX389(3.5mm plug inserted),
the 7030+ and every automotive radio I have ever tested. I suspect
that
the 770KHz is so strong is just causes the front end to "colapse".
It is funny that my PRC1000 requires at least a paper clip to receive
it.

I can receive them on a simple crustal set with just the leads to the
earphones.

I am very glad they are only 1KW and daytime only!

Terry

"John Plimmer" wrote (in part):

I would sell kidney or other spare body part tonight to buy one.
However I live less then 4 miles from a littlel 1KW MW on 770.
And we a few fairly local power houses at 590 and 630 and 1300.
On the 7030+ I could receive the 770+590 fairly strong the , the
770+630
and and the 770+1300 very strong. In a nearby park about twice as far
from the 770 station as my home, I get no mix products. The 770 is so
strong that it will show up in most receivers even with the antenna
disconnected and replaced with a 50 ohm terminator.

Is there any possibility that you have the rear-panel pre-amp turned on in
the 7030?

What happens when you add in 10 dB or so of attenuation?

Rick Kunath