Welcome to Radio VA3YW in Toronto, Canada
Long audio recording (6MB) on 40 meters using an iTALK handheld recorder (101803).
Short audio recording (1MB) on 40 meters using an iTALK handheld recorder (101803).
Photo of Icom R71A tuned to 7060 KHz during the above recording.
HP180A oscilloscope (5ms/div and 100mV/div) display of audio waveform from REC output of FRG7 receiver on 17-Oct-2003 at 7035 KHz (270KB).
Audio spectrum of 7035 KHz iTALK recording of REC output -- the red marker is at 60 Hz.
Each radio is connected to its own 15' indoor random wire antenna.
HP180A oscilloscope (5ms/div and 100mV/div) display of audio waveform from REC output of FRG7 receiver on 16-Oct-2003 at 1300 KHz (360KB).
Audio spectrum of 1300 KHz iTALK recording of REC output -- the red marker is at 60 Hz.
HP180A oscilloscope (5ms/div and 100mV/div) display of audio waveform from REC output of FRG7 receiver on 16-Oct-2003 at 29300 KHz (240KB).
Audio spectrum of 29300 KHz iTALK recording of REC output -- the red marker is at 60 Hz.
The noise is also getting into the CABLE-TV service and appears as rows of diagonal white dots on Channel 2 AM (101703 8 AM), Channel 2 PM (101703 11 PM), all the way up to Channel 6 (102303 10 PM).
Though the noise is present right across the entire HF and LOW VHF spectrum, it is easiest to track using a regular AM broadcast band receiver (Grundig Mini World 100 PE) tuned to around 1300 KHz, and can be heard being conducted into the house at the main service meter outside and along the cable TV coax entry.
So far, the noise seems to be strongest one block North at the SW corner of Roncesvalles Ave. and Fern Ave. (looking North towards corner), beside wooden hydro pole #58 and beside tree #1, and tree #2 to the South of the pole.
The pole top has a single transformer.
This location makes things a bit of a mystery because there are other transformers one block farther South, whose wooden poles do NOT sound very noisy at all.
The house is actually fed from a transformer on concrete pole #57 on the South side of Garden Ave. near Sunnyside Ave. (from where it is fed) which did not sound excessively noisy on a wet 18-Oct-2003.
The noise is most broad-band when it rains -- ie. TV CH6 and 29.300 MHz clear up when it is dry.
20-Oct-2003 was dry. Channels 2 to 6 were perfectly clear.
At 8 PM 1300 KHz was perfectly clear but 1620 KHz had S3 noise on the FRG7.
There was also some noise at 29300 KHz.
Did a walkabout with the Grundig Mini World radio tuned to 1620 KHz.
The outside service meter entry was extremely noisy as was the TV coax right below it.
Wooden pole #58 on Roncesvalles Ave. along with the two trees beside it were QUIET this time.
Walked NORTH 50' where the 13.8 KV and 600 V lines feed under ground -- the wooden pole was EXTREMELY noisy.
Walked North to Wright Ave. and West to Sunnyside Ave. -- all the concrete lamp posts along Wright Ave. were very noisy.
Walked South to Garden Ave. -- all the wooden poles along Sunnyside Ave. were quiet.
The concrete pole at the South-East corner of Sunnyside Ave. and Garden Ave. which feeds one 13.8 KV phase Eastward to concrete pole #57 on Garden Ave. was quiet.
Walked East along Garden Ave. towards Roncesvalles Ave. -- concrete pole #57 with the transformer which feeds this whole block was somewhat noisy at 1620 KHz.
Concrete pole #53, which feeds all the Cable TV Heliax underground, was EXTREMELY noisy at 1620 KHz.
The concrete post beside the house was quiet.
On returning home, 1300 KHz was all crud again, but the TV was still clear.
Tried recording the walkabout with the iTALK, but it kept turning itself off after a few minutes.
21-Oct-2003 was dry during the day though it rained overnight.
Channel 2 had light sparklies at 8 AM which cleared up by 8 PM.
Did another walkabout tuned to 1620 KHz.
The two trees beside pole #58 could be heard from 5' away again but the pole itself was quiet.
Walked West on the North side of Fern Ave. -- the concrete lamp posts were fairly quiet.
Walked East on the North side of Garden Ave. -- the concrete lamp posts were very quiet up to the church.
The TV Heliax from pole #53 crosses the road overhead to the North side and from here the poles were noisy up to Roncesvalles Ave.
(The North side of Garden Ave. is fed from Roncesvalles Ave.)
So far none of the poles or transformers can be definitely identified as THE culprit.
Continued the walk along the East side of Roncesvalles Ave. from Marion St. North to Garden Ave. -- two of the travel agencies had very noisy ballasts that could be heard from ten feet away, BUT the WORST noise is right at the TTC stop on the South-East corner of Roncesvalles Ave. and Garden Ave. where it completely swamps the radio within a 20' radius of the corner grocery store and the coffee shop beside it.
A Field Strength sweep will be done tomorrow with an SD101 diode detector read on a Mastercraft Digital Multimeter on the DC mV scale.
22-Oct-2003 -- dry, FSM walkabout at 8:30 PM -- most stores are closed.
Pole # -- mV -- Location
64 -- 4.0 mV -- 13.8 KV feeds underground here - Roncesvalles Ave. - West side
68 -- 5.0 mV
74 -- 6.8 mV -- at High Park Ave.
T63 - 1.0 mV -- light pole on Roncesvalles Ave. - East side
T61 - 0.9 mV
48 -- 0.8 mV -- N.E. Fern Ave at Roncesvalles Ave.
53 -- 1.2 mV -- Garden Ave. South side - pole feeds Cable TV underground
55 -- 0.6 mV -- walking West to Sunnyside Ave.
57 -- 0.7 mV -- has transformer feeding South side of Garden Ave.
59 -- 0.6 mV
61 -- 0.2 mV -- at Sunnyside Ave.
All other poles along the East side of Roncesvalles Ave. down to Pearson Ave. were under 0.2 mV, even the noisy area at the TTC stop at Garden Ave.
Sometimes the meter would momentarily swing negative to several mV while walking but would settle down to zero while stopped -- maybe the body, acting as a capacitively coupled ground for the meter, was picking up too much low-frequency noise.
The RF probe will be re-designed.
15-Nov-2003 Channel 6 noise is still here, wet and dry.
Re-designed the RF probe and connected it to the meter on the DC 200 uA scale for increased sensitivity.
Testing with a 49 MHz room monitor, gives a reading of only 120 uA on the 200 uA DC scale, with the 6" probe antenna touching the monitor antenna, and 360 mV when switched to the 2000 mV DC scale -- current through the 1 Megohm shunt resistor should be only 0.36 uA.
The setup seems to be three times more sensitive using mV instead of uA (this is opposite of what was expected) -- will try both in the field.
If both results turn out to be marginal, the choke inductance will be increased to move the response down to HF from VHF to narrow down the area, and a VHF loop antenna will be constructed when zeroing in on the source.
Feb 2004.
Testing has been suspended indefinitely due to an illness in the family.
AS
