I had an interesting fault with a DC powered phone charger in my ute and prior to that, in a 60 series landcruiser sahara, I fitted a double din Pioneer head unit to the sahara and noticed when the phone was being charged, the FM side of the pioneer tuner went quiet, when I pulled the charger from the Cig socket, the tuner burst into life again, it was being completely blocked by the radiation from the little SMPU in the cig lighter charger, clearly this must operate in the hundreds of MHz region.

The authorities are letting this stuff into the country by the thousands (millions) of tons..... they know it is coming in but wont do anything as it is the big end of town importing and selling it....
If I (or any other little person) sold anything like that I would be hung, drawn and quartered....

Interestingly the "radio" in my ute is just a tinplate box driven by the body computer... but it works well...even on the AM band..surprisingly..

Some of the "modern" radios are literally Software Defined Radios and have no front end and as a result are as broad as a barn door!!!

AC mains powered device chargers are more problematic when the charger is not actually charging anything, but it is left switched on at the GPO..

The bigger the big end of town, the worse the RFI.....

I seem to recall in the WIA magazine, there was concern being aired about broadband over power lines and the RF-I this may cause, well folks Broadband noise over the power lines have been here for decades, it is just getting worse....!

Any body fitted a HF transceiver into a V8 cruiser ute?.... they literally growl, scream and yelp out of the rig's speaker at about 2MHz....after turning the ignition on.. but they are quiet on the factory fitted tuner head unit, just low on AM performance, the tuner is good but the antenna is the culprit there..
Don't know about the wagons, 'think they are much better... RFI wise..

Wait until your internet enabled refrigerator starts to upload the weekly food order to "colesworth" and try listening to your AM radio.. not to mention all these IoT devices sapping your internet account....

Travelling up and down the Stuart highway and listening to RN on 684 or RR on 783, the signals are usually fairly weak but readable, then a truck goes past with all those LED marker lights burning, HID or LED driving lights etc, there is a momentry burst of hash, made up of all those LED lights which have a constant current driver, (read: SMPU power supply), literally dozens of them, one in each individual light fitting, the inverters in the engine control computers and the IBGT switching devices controlling the fuel injectors... and the list goes on, all making up a multitude of wideband RFI noises..
Even the AVR in the alternator is a SMPU...!! adding its bit of RFI.....

SMPU in the cig lighter charger, clearly this must operate in the hundreds of MHz region.

Harmonics galore.

My car phone charger puts hash into the FM radio, so once the phone is charged the thing gets unplugged from the cigarette lighter socket.

Most of my computers are fairly quiet hash-wise, but I have one old XP box that radiates hash on AM for 100 metres in all directions, totally blocking all reception in the house. I think it might be an issue with the power supply.

And then there's the cheapie digital set-top box that also wipes out AM reception, even when off. It has to be turned off at the powerpoint to keep it quiet.

A bit off topic, but I've yet to find a set-top box that doesn't have poorly-written software. Every one I've tried has serious bugs.

Even my fairly new flatscreen from K-Mart (which wipes out the nearby AM radio) has no sound on half of the HD channels.

I've yet to find a set-top box that doesn't have poorly-written software. Every one I've tried has serious bugs.

I have a Topfield TBF-100HD bought years ago. I've never had any problems with it and I find its program schedule more intuitive than those on many digital TVs.

You didn’t mention if the noise is on the entire band or near the frequency of interest.

Since you mentioned “lengthening the long wire”, it might be worth investigating a tuned magnetic loop antenna.
They typically provide less signal, even when tuned to resonance for a frequency,
and limited tuning range across a band, but better overall signal to noise ratio.

I do agree that looking for local interference should be a priority though.
Fortunately, even though in a city, interference on MW has never been an issue for me at all.

it might be worth investigating a tuned magnetic loop antenna

I considered mentioning a loop, especially for its directional characteristic and consequential ability to null out unwanted stations.

It might be useful for zooming in on local noise sources, too.

I made a frame antenna, approximately 500mm square with 10 turns, tapped at each turn and tuned it with a salvaged single gang whilist playing with the taps.
Then I made a single transistor emitter follower preamp, more for buffering than gain, fed from a 216 9v battery.
This was fed into a 4 turn loop at one end of a ferrite rod equipped transistor radio and found I could null out the noise and peak up the wanted signal.
Sometimes the noise appeared to be in the same direction as the wanted station, but it proved a point....
Found it helpful in stormy weather too, as long wire antennas were more prone to picking up lightning static, all antennas will pick up QRN to a degree though.

This was in the era when the majority of interference was what we called "power leak" a 100hz fizzing/buzzing sound.. lots of 22Kv leakage etc...
The power leak type interference was right up to the bottom of 2mx when I used to work SSB on 144.1MHz...
Plus the usual radiation from CRT TV's.... and fluro lights.
This was before SMPU's become in widespread use like today.

Hi GTC,
I didn’t ever get the result for MW despite being pretty enough, but since have had very good results with some for HF.
It deserved a second chance actually. Here with a tile roof, it’s elevation from the ground to my head height would probably
tune it across another 100-200kHz.

This is very interesting. I am sitting in my workshop tonight, I can’t tune a thing in on my valve set- tecnico fortress , model 1050. It’s my first attempt at radio repair. Or despair... yet last night, I had this set and my gec radiogram, model bc7443, picking up 2nm from the hunter valley, some 900 klms away. The radiogram has no external antanae wire attached. I thought my sets were having more problems, but I now suspect external interference. I’m turning things off all over the house as said earlier in this post, but no help so far. I’m in MALENY qld, a little town, very foggy tonight, I don’t k ow if that hurts signal. Last night was similar, just raining as well. It’s all very curious.

Try the loop antennas, it will cut down a lot of noise, I built two loops for lightning detection mounted north south and east west.
They were tuned for around 13kHz, they worked well.
But I had re-tuned them for the airport NDB frequencies and the MW band and could phase them, brilliant.
I want to remotely tune them with varicap diodes at some stage.

I have an issue where I live, between Brisbane and Toowoomba to the west, I listen to 4KQ on 693kHz( they play a lot of 50-70's stuff), The antenna pattern is mainly north south and covers Brisbane and the north and South coasts, and I think they may reduce the power output at night.
It makes it very difficult at times.
I haven't tried the loops recently, I found them a few weeks back during a clean up.
I could just use the DAB+ receiver and run it through my two valve am modulator. According to the DAB+ Australia web site, I can't receive DAB signals at my place, I get great DAB+ signals.
But it's not the radio picking up the signal, so I can't see the point.
I hear most higher power stations around the country, most seem to be the ABC stations, although I have never heard any from the Northern Territory.
I listen to ABC Melbourne on 774kHz driving on the way to work most mornings in winter, Starts to drop out when I go up Milton road near the XXXX brewery, which is a strange thing, (nothing from the south gets pass XXXX)

Have a look at this site's PDF for ideas.
http://www.knlr.com/audio/wcgb/Loop%20antenna/PowerPoint/The%20Simple%20Box%20Loop%20Antenna.pdf
for a quick test you can build one out of a card board box, as per the pdf.
you will just have to add a small one or two turn loop to couple the radio to the loop antenna.
The loop from the radio is not tuned, just placed next to the main loop antenna and connected to the antenna and earth connections. on the radio.

Quote: "I built two loops for lightning detection mounted north south and east west."

I have cogitated building a loop antenna on the same principal as a direction finder, ie two loops outside set at right angles, each feeding their signals to where you are inside, to two coils also set at rights angles. These last two coils are interrogated by a rotatable coil and its signal sent to your radio. This would be ment to be equivalent to a rotatable single loop antenna, but not needing any antenna rotating gear and its complications.

Is this what you have built Flukeoneseventyfive?

When looking at the design of direction finders it is made clear that coil winding and alignment and arrangement of feeds between them is critical for accurate performance. However for a receiving antenna for a radio this should not be as critical, though dead spots in reception would have to be avoided.

I would be interested know if you have built something like this.

Have you tried directing your LW antenna Jamie?

I love listening to 2CH. I live 600km SW of Canberra, pointed my LW NE and 2CH now screams in (night time only)

Worth a try mate, especially if you are in the bush and have a few acres to spare.

I just read some members' comments on loop antennas, so I thought it appropriate to show my humble home-made efforts.

they are specifically designed to track lightning discharges beyond the horizon, and form part of my research work involving pre-seismic electric signals.

Oh, by the way, the antennas are mounted on pivoting brackets enabling directive control toward signal sources of interest (read AM radio stations that still play "real music")

STC830
I used the two loops fed into a couple of op amps and then fed into the sound card, left and right channels.
the software took care of the rest.
with a couple of stations around the country and overseas, we had good triangulation and using the online time sites, the computer clocks were accurate enough to display the position of the source of the lightning, this was around 10 years ago.
there are more modern devices around now, that use ferrite rods.
and the software is much more refined.
A lot of different signals around those frequencies are from natural sources, it is good just to listen to the signals generated from lightning and solar flares.
Have a look here.
http://www.auroralchorus.com/natradio.htm

There is some study and speculation, that there are VLF signals generated prior to earth quakes, and this could help with a warning of an impending earthquake.

For info: I have some fading in and out on 2CH on a long wire, West of Wangaratta Vic. Its over 500 Km to it as the Crow flies.

Late afternoon & Night.