clifford wright wrote in
:

atec77 wrote in :

On 17/09/2011 1:08 PM, clifford wright wrote:
Doug 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.
My question relates to the qrm you accept , we recently solved a
problem here with an HT line which was determined by various means to
be at fault . The power company refused to consider their spark
transmitter line was at fault but after taking legal advice and making
formal complaint they fixed the problem replacing some ceramics
dropping the qrm some 3 to 4 s points and oddly the incoming 240vac
got much cleaner . You do as an individual have rights so although
laudable in the attempt
to remove the noise ( and I admit I have not been studying the
discussion) I don't remember mention of your complaints process , feel
free to refresh my memory if you wish , once sourced the problem as
you discovered may be addressed by various methods , personally I have
several tx and rx antennas which when switched between various loop
and wires is very successful in assisting communications plus the use
of dsp filtering has altered the radio experience considerably ,VA3AGM
did some very useful work which is inexpensive and works very well
with my sdr and may be used equally with almost any radio you desire .
Personally I don't particularly like digital process and revel in the
audio on my KWM2 and AWA but sometimes have little choice , so maybe I
can help ?


Ah now I understand! Well both my neighbouring fellow ham and I had
already follwed this up as far as we could go, Indeed we did get quite an
improvement on the original situation. We had the radio inspectors from
Auckland out here twice and weny out on a survey with them by car, with a
whole lot of gear to find tha sources of the interference.
This resulted in a reduction from S8 on 40 M down to about S5/6. The
trouble is that I have always been interested in weak signal work on 20
when I work the Antipodes of the Auckland area (Spain and the Western
Mediterranean) when the band is apparently very dead. VK5BR's device got
the noise down almost as much again and I have hopes of an improved and
higher Q phasing network imprving on that.
BTW my fellow ham actually works for one of the local power companies!
NOT our local one unfortunately!
Of course out here in the country we always have the dreaded electric
fences clicking in the background!
As to aerials. Well I have a reasonable QTH near the top of a hill, but
as I have other hobbies, including amateur astronomy I don't have
unlimited space (the observatory has to go somewhere).
So I have a G5RV with proper open wire feeders and the mast that supports
it is tuned to behave as a 5/8 wave vertical on 20m as well.
Overall I would say that the vertical is about 4 Decibels worse than the
G5RV as far as noise pickup is concerned.
My noise antenna runs along the top of a fence below the G5RV for about
3/4 of a wavelength at 14 MHz.
As an old timer I'm afraid that I am not very enamoured of digital radio
, it's OK in synthesisers etc but doing it all in software takes all the
"human" interface out for me. I still use a 1918 morse key for example.
Some of the gear I have seen lately, you might just as well get on the
internet!!! However I still build a lot of my own gear and the commercial
stuff I use has been heavily modified,improved and upgraded.
73's Cliff Wright ZL1BDA ex G3NIA


Follow up to VK5BR noise canceller as promised.
Well it is all going quite well. The input coils have link windings to
match the input to 50 Ohms and are all wound on the appropriate Amidon
toroids.
Works very well against local QRN on 3.5/7 and 10 MHZ bands.
Not as effective on 14, 18 and 21 Mhz. However I suspect that this might
be partially due to the ferrite grade used in the rf transformers.
Amidon only specify it up to 15 Mhz and I am going to try a grade specified
to 30MHz when I can get some in. BTW I have used the later circuit with 2
transformers to reduce rf losses. The RX/TX circuit shown works well and
doesn't seem to cause any damage to the unit with 200 watts going to the
antenna.
Altogether a very interesting circuit and worth while for those doing weak
signal work, or in a very bad QTH.
One major point however. If you use a vertical and have a horizontal noise
pickup antenna you may well find it very ineffective. Probably it
overwhelms the adjustment range of the RF phasing control, but I have not
determined this yet.
Give it a try if you have problems.
73's Cliff Wright Helensville ZL1BDA ex G3NIA NZVRS