clifford wright wrote in
:

Good day all!
My latest build is a version of the VK5BR noise cancellor.
So far (using different toroid cores from those specified) I have got
about 3 "S" points of noise reduction.
I am expecting a shipment of cores from Amidon in the next few days
and will try the final version with 2 FT50-75 cores as specifid in the
later "Amateur Radio" article.
Basically though I am quite pleased with it. It means more
adjustments, but in a rural location, but with bad power line noise,
it seems to help. FYI, Don't go by the "radio communication" circuit.
It has several errors. Look up VK5BR's own site with all the
corrections. It would be very intersting to hear of others experience
with this gadget. Anyone else made one?
Cliff Wright ZL1BDA ex G3NIA


Well the unit is all operating now with the proper ferrite core
transformers.
Results vary with band but on 7 MHz I an getting about 20 dB reduction in
background QRN. 14 MHz is not quite as marked but still about 15 dB.
Quite worthwhile! But one has to remember that this circuit reduces the
LOCAL noise background not ionispheric noise or QRM.
Overall I would recommend it to those troubled by electrical noise.
However I do have some reservations about the Low Q chokes used as front
end tuned circuits. I suspect that the phase shift one needs is not as
accurately obtained and it might work better with some high Q toroids in
their place. That will be tried next as soon as they arrive.
Another thing- Does anyone know of a source of adapters from surface
mountto DIL IC's. This is becoming more and more necessary as newer chips
are NOT being produced in DIL packages. I've had a lot of trouble with a
motor controller chip for an electric bicycle which was 24 pin Surface
mount only.
Clifford wright ZL1BDA ex G3NIA.

clifford wright wrote in
:

clifford wright wrote in
:

Good day all!
My latest build is a version of the VK5BR noise cancellor.
So far (using different toroid cores from those specified) I have got
about 3 "S" points of noise reduction.
I am expecting a shipment of cores from Amidon in the next few days
and will try the final version with 2 FT50-75 cores as specifid in
the later "Amateur Radio" article.
Basically though I am quite pleased with it. It means more
adjustments, but in a rural location, but with bad power line noise,
it seems to help. FYI, Don't go by the "radio communication" circuit.
It has several errors. Look up VK5BR's own site with all the
corrections. It would be very intersting to hear of others experience
with this gadget. Anyone else made one?
Cliff Wright ZL1BDA ex G3NIA


Well the unit is all operating now with the proper ferrite core
transformers.
Results vary with band but on 7 MHz I an getting about 20 dB reduction
in background QRN. 14 MHz is not quite as marked but still about 15
dB. Quite worthwhile! But one has to remember that this circuit
reduces the LOCAL noise background not ionispheric noise or QRM.
Overall I would recommend it to those troubled by electrical noise.
However I do have some reservations about the Low Q chokes used as
front end tuned circuits. I suspect that the phase shift one needs is
not as accurately obtained and it might work better with some high Q
toroids in their place. That will be tried next as soon as they
arrive. Another thing- Does anyone know of a source of adapters from
surface mountto DIL IC's. This is becoming more and more necessary as
newer chips are NOT being produced in DIL packages. I've had a lot of
trouble with a motor controller chip for an electric bicycle which was
24 pin Surface mount only.
Clifford wright ZL1BDA ex G3NIA.

There are a couple of adapter board vendors out ther. Unfortunately,
they typically cost more than the IC's. Digikey sells "surfboards", and
there are also these guys:

http://www.adapt-plus.com/products/a...smt_board.html

http://www.schmartboard.com/index.as...mttodip&id=450

Doug White

Doug White wrote in
:




Thanks Doug I will follow that up.
After all the chips only cost $5 each so paying up to $10
for an adapter wouldn't be too high a price to pay, it saves so much
trouble. I'm 71 and I surprised myself in that, I was, in the end able to
wire all 24 pins. I'll have to redo a few though and I'm very concerned
about the durability of the joints under vibration as it is an electric
bike controller for a BLDC sensorless electric motor.

Atec77. I'm a bit puzzled about your response!
The whole idea of the system is to reduce the QRN we get around here from
nearby elderly 11 Kv power lines above ground.
W have underground power in our subdivision but the crud is (We have tested
it) radiated from the lines themselves.
Obviously it is MUCH easier to null out local stuff like this than randomly
phased and levelled long distance signals. That is what VK5BR set out to
do, with some success.
When I have my new delivery of toroids I will try out my theory on the
tuned phase shift network on the noise amplifier. If there is a notable
difference I'll post it here.
Best Regards Clifford Wright ZL1BDA ex G3NIA.