Radio in broadcast shadow?

[Tonyz]

Call me strange but I like waking up and hearing the ABC news on the clock/radio/alarm thing. Recently we moved out of town 10k but can see the radio transmitter tower over the roof of our shed.
Whats annoying is the constant static on any station, can hardly hear whats being said and a s**t noise to wake up to.

The electrical retailers in town all say we are in a shadow. Maybe but then why (and I have not asked them this Q) why does the car radio be normal?

Even tried a new radio/alarm... no difference. Outside car arieal (thats a nasty word to type) mounted on verandah does not help either.

So query is ... what else can I do?

even thought about 12 volt battery under the bed hooked up to car radio but how would that turn itself on.

[BobL]

If your car radio is normal then you have something electrically noisy on your mains.
Turn everything else off and systematically turn things back on to identify the culprit.

[Twisted Tenon]

I find that certain light bulbs will cause a lot of static when I listen to 702.

TT

[Tonyz]

what type of light bulb TT?

[Twisted Tenon]

what type of light bulb TT?


This is going to be vague, sorry about that. There are two types. One is a touch light. You tap the base for 3 different degrees of brightness. This is in the down stairs bedroom and will affect the radio upstairs. I'm not sure about the other lights. These are recessed into the ceiling about 2" in diameter. I can't have these on with the radio. The circular fluro tubes don't cause any problems.

TT

[Tonyz]

If your car radio is normal then you have something electrically noisy on your mains.
Turn everything else off and systematically turn things back on to identify the culprit.

Bob I hear what your saying but we have not changed any electrical appliance or things since moving from previous house.
We moved here into a shed (house wasn't finished) and picked up the static and put it down to metal shed etc but now in house timber foundations, timber frame etc etc the noise still continues.

[BobL]

Bob I hear what your saying but we have not changed any electrical appliance or things since moving from previous house.
We moved here into a shed (house wasn't finished) and picked up the static and put it down to metal shed etc but now in house timber foundations, timber frame etc etc the noise still continues.

Sure
BUT
without you doing a thing some appliances amy develop a problem during its life time, overheating, electrical break down, misuse.

How far is the shed from the house? If the shed is large and close enough it may still affect reception in the House.
Does your house have a metal roof, ours does and the TV reception with an internal aerial is rubbish and reception via and external aerial is affected by reflections from adjacent houses with metal roofs.
This problem was cleared up when digital TV arrived. Now

Along the same lines , analog radio reception in my metal clad shed has never been great but as soon as I turned on any VFD I lost nearly all radio reception.
Reception improved a little by using an external aerial - just a bit of wire hanging out the window but it was still very noisy when runnibf VFDs.
When I received a digital radio as a present for the house I tried it in the shed and this cleared the static problem completely. The signal used to drop out every now and then but that was cleared up by extending the aerial with a 1m length of wire inside the shed.

[Tonyz]

VFD ? something something devises?

Yes metal roof.

Will try a digital radio, keep invoice and return if not the answer cheers

[BobL]

VFD ? something something devises?
Sorry, VFD = Variable speed drive, used on lathes etc
Have since found these can both radiate radio static and send it back down the mains.


Yes metal roof.
Yep won't help it much.


Will try a digital radio, keep invoice and return if not the answer cheers

Did you try an external aerial on the analog radio - or even just run it outside the house?

[Boringgeoff]

In my shed I listen to a FM station which is about 70km away and had a lot of static and fluctuation with the small telescopic aerial. I made an external FM antenna tuned to the frequency (100.1) and now it goes really well. I removed the antenna from the top of the radio so that I could hard wire the feed wire straight in and the radio earthed to the shed frame to complete the circuit.
Cheers,
Geoff.

[Tonyz]

bummer we dont have digital radio over here. Spoke to salesman in leading electrical store...."you are in a shadow, nothing can be done, live with it..I'am your neighbour 4 blocks down we have the same problem".

[Bohdan]

If you listen to a particular station you can get an external directional antenna (like a TV one) and point it at the station.

[Chris Parks]

bummer we dont have digital radio over here. Spoke to salesman in leading electrical store...."you are in a shadow, nothing can be done, live with it..I'am your neighbour 4 blocks down we have the same problem".

The why does the car radio work? Another approach would be to rip a head unit/radio and speakers out of a wrecked car complete with aerial and use that. Get one with a CD and usb/auxiliary/bluetooth and the media world opens up and a 12 volt battery and trickle charger will power it ok. A good one would be out of a VS Statesman or later as they had a multi disc stacker in the boot if CD's are important.

[groverwa]

Have a look at What's wrong with my radio reception? | ACMA (http://www.acma.gov.au/Industry/Broadcast/Spectrum-for-broadcasting/Spectrum-radio-broadcasting/whats-wrong-with-my-radio-reception) as there is a shed load of info there.

A few instances in my experience with interference are:-

1. After we installed a Commander fone system at the Exmouth Telephone Exchange we got a call from the radio interference mob saying that the police who were next door were complaining that their 2 way had unacceptable noise when close to the station.
It turned out that the phone system used a switched mode power supply that generated the interference and my solution was to wrap aluminium foil around the cable and connected that foil to the earth system. This acted as a shield and drained the noise to earth.

2. Many years ago, in PMG days (showing my age now). we had a new comm system installed between Kununurra and Wyndham and this worked well until the dry season and got noisier and noisier. We found that the saucer shaped insulators on the power lines in the direct transmission path were of a frost free construction which meant that there was a small leakage through them that when dust accumulated in the ball and socket joints that connected the insulators in series this dust was a resistance to that leakage current and acted as a noise generator. The SEC fixed the problem by welding a strap across the ball and socket joints. As a side giggle for those of you old enough to remember when a license was reqd to use a radio we tied a yagi antenna onto roof of the landrover, connected it to a good comm radio and drove around until the offending noise source was found. We had wised up the Post master that we were telling anyone that wanted to know what we were doing that we were trying to find any unlicensed radios.

[ian]

The why does the car radio work? probably because the metal in the car acts as a ground plane for the antenna.

getting on shaky ground here, but my understanding is that a ground plane helps to concentrate a weak signal.

[BobL]

The next step has to be seeing if the radio runs outside next to the car, power it with an extension cord - tell us what you hear.

[malb]

AM or FM broadcast?

AM can be absolutely blown away by impulse noise from a huge range of sources or high power transmissions from other AM stations in very close proximity, but can penetrate into valleys etc within the coverage range of the transmitter.

FM is quite immune to impulse noise, but is very directional and literally line of sight reception. If you are in a regional area and getting regional ABC or Local ABC (Adelaide AM) from a local FM translator, the translator/transmitter will be mounted as high as practical in the area intended to be served. The radiation pattern of the transmitter would be optimised to give good coverage to the township area first, then coverage to as much of the surrounding area as possible. However because the broadcast is quite directional, if you are in a valley etc, even in visual range of the transmitter tower, you could be in a low signal area for two reasons. The first is that the transmission antenna may have been optimisised to minimise the signal being radiated down into valleys etc in order to maximise overall coverage, the second is that the signals at that broadcast band are very directional and will not bend to fill valleys or flow around hills, buildings etc to provide coverage in some areas. Both of these can place you in a broadcast shadow where reception is almost impossible because there is no broadcast signal to receive.

[Pete57]

Trying walking around with a battery powered radio to see how it compares inside, outside house and verandah. Maybe the external antenna on the verandah was not a good location. Battery radio might help find a better signal spot for an antenna.

[ian]

The aerial inside a clock radio is usually a ferite rod and very directional.
Although yiou can see the transmitter, the signal from the transmitter may be aligned in a way that means the signal in yor direction is very weak.

Try
locating the radio near a window on the side of the house facing the transmitter.
rotating the radio horizontally and vertically to see if the noise varies depending on the radio's orientation.
as already suggested, repeat this location / rotation regime outside.

My guess is that the broadcast signal in your direction is too weak to get past or through the metal shed and/or house roof.
the solution is likely to involve an external aerial mounted on the roof of the house.

[Tonyz]

I appreciate all the advise you guys have given. However it now turns out there is nothing that can be done about this crazy situation. Even ABC local radio jocks advise verbally its one of the joys of rural living on Eyre Peninsula.

Can this now be closed.

[rrich]

Here is my guess.

You have electricity in the shed. I assume that you also have a panel of sorts to supply the shed.

If the panel has its own ground rod, there is a ground loop. Move that ground to the ground bar in mail panel. That should solve your static problem.