This is noise that chokes won't touch

[bob85]

pics for Eddie,
this is the noise i have from 19mhz to over 36mhz, highest signal is on 24mhz & peaks about every 11khz using the gainmaster as an antenna,
its there on my triband vhf uhf vertical up into 40mhz band at a much lower signal, that antenna is halfway between the house & the gainmaster,

unplug the coax & shove a 9ft length of wire as a sniffer into the rsp1a & the signal is not here in the house,
the gainmaster is picking this shit up directly,
removing the 2x ft240 toroid choke does nothing at all, adding a w2du choke at the radio does nothing at all,






after 3 days of wet & wind i hope its just next doors electric horse fence arcing & going nuts,
the signal is unstable in frequency & strength, it has been as high as s9 & low as s5 over the last 18hrs or so & drifting up and down,

 

[sp5it]

Dirty switching power supply / voltage converter / cell phone charger.
LM2767 junk.

 

[bob85]

I have none of that near the antenna, no noise in house or its below the general noise floor in the house,

only thing close to my fence is the electric horse fence & im betting its a dirty switching inverter in that fence box doing it or its blown over & arcing onto the fence,

im in trouble if its not that, i can only hear people local to me & some of them are noisy.

 

[sp5it]

If it's electric fence I think you need a few ceramic capacitors, ferrite rings and do some work with inverter.

 

[oldtymer]

unplug the coax & shove a 9ft length of wire as a sniffer into the rsp1a & the signal is not here in the house,
the gainmaster is picking this shit up directly,
removing the 2x ft240 toroid choke does nothing at all, adding a w2du choke at the radio does nothing at all,

The only way you can be positive that it is not some device in the house is to hook a battery to the radio and shut off the main breaker in the service panel.
If the noise is still there it's coming from an out side source.

 

[bob85]

That's the first thing i tried, its not coming from the house or the house either side, i would hear it on the 9ft wire,
gainmaster is further away near my fence, the horse fence runs within a foot or so from the far end of my fence,

i will go out with a battery & cb from the loft tomorrow & find it i hope.

my yupiteru is stripped down to nickle plate the battery contacts so i can't run out side sniffing around,
i loaned my snoop loop out to somebody that never brought it back so may need to make another,

if its the fence it will be obvious when i get near it.

 

[bob85]

can't wait for tomorrow so i found an old uniden, used a multimeter lead as a sniffing antenna & alarm battery to power it,

its the horse fence,

its not coupling into my fence, noise is no higher 2" from it as it is 6 feet from it but when i go up near the horse fence its MUCH stronger, as i walk away the noise goes up and down getting lower, after 50 yards its almost gone on the sniffing setup

The fence has never been turned on since it went up, the horses just think its turned on,
its on now & noisy as hell.

 

[Shadetree Mechanic]

Hook the fence up to a ground rod and see if the noise goes away.

 

[bob85]

its my cousins wifes horse fence,
we were talking a couple of days ago about him redoing his fence because one of his dogs keeps escaping when people let fireworks off & its bonfire night soon so plenty of fireworks tonight,
im betting its to try and stop the dog escaping because the horses don't need it.

we will work something out, probably be off again after Nov 5th or when folk stop letting fireworks off,
im lucky, my german shepherd bitch sits watching them, not scared at all.

 

[Slowmover]

That's the first thing i tried, its not coming from the house or the house either side, i would hear it on the 9ft wire,
gainmaster is further away near my fence, the horse fence runs within a foot or so from the far end of my fence,

i will go out with a battery & cb from the loft tomorrow & find it i hope.

my yupiteru is stripped down to nickle plate the battery contacts so i can't run out side sniffing around,
i loaned my snoop loop out to somebody that never brought it back so may need to make another,

if its the fence it will be obvious when i get near it.

“Loaded with #4 Buck . . . .” (is where that story picks up when I tell it)

.

 

[Handy Andy]

Well, if it's the fence, is lengths of it resonant at any wavelength that can interfere with that IF?

Reason I say IF because its' not harming 27MHz as a carrier - this seems to be more of a reflection, termination problem - having a side or three close to a resonant length your hearing in 11kHz steps tends to make me think this is due to line length not a machine noise problem - it's simply acting as a simple radiator - the power on the line and it's capacitance/inductance (due to length, height and spacing) makes this a prime candidate for Resonant Length problem

 

[bob85]

i had a quick look today when i went out metal detecting in the next field,

its a 3 wire fence spaced about 18" apart & theres a gap in one corner,
no idea where the box is or its length, could be 2 fences going in different directions around the 1acre paddock,

i have spurs every 11khz from 19mhz to over 40mhz & probably below that if i had a decent antenna up for lower frequencies,
when i put the curser on a spike i have signal sometimes as high as s9 on 24mhz,
it moves before i take the pic & some shots show no signal on the meter,

the strength of the signal on a cb or the icom 703 also changes over time, not tried other radios.