PDA

View Full Version : Aerial question


Onan the Clumsy
28th Sep 2005, 00:59
I have this under-the-cabinet-radio in the kitchen and it used to work flawlesly...until I bought a new fridge.

I put the fridge sort of close to the radio, but in fairness exactly where the old fridge was. Now all I can get on the radio is hissing. If I hold onto it, I can hear the progran a little, but how much does that suck? It's not for every station either, but it IS for the ones I want to listen to :(

So I need help. Why does it do this? I'm assuming it's an aerial/antenna problem (the radio doesn't have an (external) one).

What can I do to fix it?

TIA OtC

barit1
28th Sep 2005, 03:08
Was the old fridge grounded (earthed)? Is the new one?

Are you trying to receive FM or MW or both?

flyblue
28th Sep 2005, 06:08
Onan, I have the same problem with the radio in my bathroom. If I want to listen to France Info (MW) it I can't switch the mirror lights on :{ (FM works well though)

seacue
28th Sep 2005, 06:28
O-t-C,

Your new 'fridge may well have microprocessor control with poor shielding (screening) and filtering. Does it have a three-wire plug? Is it plugged directly into a three-wire outlet - without an adapter that would break the ground lead?

As others asked, is the problem on AM or FM?

Are you sure it started exactly when the new 'fridge arrived? IBOC / HD digital radio is starting its rollout across the USA. Stations transmitting IBOC interfere with weaker stations up to two channels away. The problem is worse on AM than on FM.

"IBOC" means "in band, on channel" piggybacking digital content on existing AM and FM stations. Except it isn't "on channel", it is actually transmitted on the adjacent channels, thus the interference.

US broadcasting stations rejected DAB/Eureka digital broadcasting used elsewhere since it would have altered the "pecking order" of station powers.

seacue

IFTB
28th Sep 2005, 06:57
Onan ,
What brand of beer do you store in your fridge?
Some beers reach parts that other beers can't reach, hence the interferance with your radio.
or, as "all I can get on the radio is hissing", have you seen the cat recently? He might have got squashed behind the fridge?

tony draper
28th Sep 2005, 07:16
Move the fridge around the kitchen until you find a position where it does not interfere with the radio then leave it there.
:rolleyes:

SLFguy
28th Sep 2005, 07:29
Is it a VHF fridge?

ORAC
28th Sep 2005, 07:41
I believe this is referred to as "white-out", paint the fridge black. Alternatively, get some chicken wire and build a faraday cage...... :cool:

tony draper
28th Sep 2005, 08:00
Mate of mine had a job instaling a telly and aeriel in a farmhouse,he spent hours up on the roof swinging said aerial hither and yon,as the farmer kept coming out shouting "thats no good ! thats no feckin good" at the finish he lost patience and flung the aerial down into the farmyard where it landed in the dung heap,farmer comes rushing out shouting
"thats perfect leave it there"!
:E

Spent many a hour on roofs in howling gales and rain doing the same,weird feckin things is aeriels.
:rolleyes:

Bre901
28th Sep 2005, 08:38
Madame Flyblue If I want to listen to France Info (MW) it I can't switch the mirror lights on You shouldn't listen to France Info for more than 15 minutes in a row, or you might get bored to death. :E
And why do you want to listen to it on AM when FM is much better ? :rolleyes: :rolleyes:
Frequencies available here (http://www.radiofrance.fr/chaines/france-info/ecouter/frequences/)
please note I refrained from posting any frequency which could give hints on your whereabouts :suspect:

teeteringhead
28th Sep 2005, 08:39
get some chicken wire and build a faraday cage ... won't the chickens object if you start keeping faradays as well ..........:rolleyes:

I Love This Show
28th Sep 2005, 12:17
Sounds like electrical interference to me :8

On a wierd note - I drive a new LR Defender TD5 with all the electrical engine gizmos. When I put my phone in the centre console and start the engine, it goes into camera mode for about 5 seconds before going back to normal... spooky!

HowlingWind
28th Sep 2005, 13:14
Living in America, you probably eat out every night at quality establishments like Outback or Long John Sliver, so food storage is really just a waste of space and needless energy consumption. Take the fridge back -- let's face it, it was just a pointless attempt to impress your neighbours in the first place. Use the extra room in your kitchen for something useful, like a tasteful armoire. Keep the beer in ice chests -- that way, you can have one in every room in the house. :8 :D

GearDown&Locked
28th Sep 2005, 14:28
On a wierd note - I drive a new LR Defender TD5 with all the electrical engine gizmos. When I put my phone in the centre console and start the engine, it goes into camera mode for about 5 seconds before going back to normal... spooky!

Imagine the same phone in the centre console (pedestal) of an airplane ...... :eek:

GD&L

colmac747
28th Sep 2005, 16:35
Would it be an idea to get one of these (http://www.completeoutdoors.co.uk/test/default.php?cPath=40) so one can joyfully tune about one's wireless without any electromagnetic interference from said fridge?

Jerricho
28th Sep 2005, 17:05
Under the cabinet radio?!?!?!

WTF?

You gone soft mate.

;)

WTF
28th Sep 2005, 17:27
WTF?

You gone soft mate.Speak for yourself, Jerricho. Please leave me out of this. :cool:

tilewood
28th Sep 2005, 17:34
Is the fridge full of beer? I find that once the I have consumed
all the cans everything sounds better!!

:ok:

frostbite
28th Sep 2005, 17:46
The fact that it improves marginally while you hold it pretty well guarantees that it's using you as an aerial, and that's where it's deficient.

Is there nowhere you can attach even a simple wire aerial?

seacue
28th Sep 2005, 18:34
The fact that it improves marginally while you hold it pretty well guarantees that it's using you as an aerial, and that's where it's deficient.
I think not. It is more likely that the radio is lonely and feels that you now love the new 'fridge more than the radio. Just keep holding the radio and saying loving words to it for an hour or two each day and in a month or two it will probably be back to its old self.

It would probably appreciate being fed especially pure mains power. Show that you care.

Glad to be of help.

sc

Jerricho
28th Sep 2005, 20:34
Sorry WTF......

I'll try to refain from taking your name in vain again :p ;)

planepsycho
29th Sep 2005, 00:59
Uh, did you ever think of MOVING THE RADIO somewhere else?

:confused: :rolleyes:

broadreach
29th Sep 2005, 01:08
This thread is giving me goosebumps. Went up the iron-rung-bolted-to-the-concrete-shaft ladder this afternoon to see where I'm going to place a vhf receiver antenna. Never been up there before, amazed to find there are more aerials on my building's roof than residents in the building. TV, satellite, hf, you name it. Coaxial cable in all directions and at all levels. And the building immediately adjacent packed solid with cellphone repeaters or whatever they're called.

Seacue, you sound knowlegeable. My antenna will have line-of-sight to the harbour which is what I want, but am I likely to have any sort of interference?

Onan the Clumsy
29th Sep 2005, 03:04
Uh, did you ever think of MOVING THE RADIO somewhere else? I can't. It's an under-the-cabinet radio, so I'd have to move the cabinets as well. **** that!


Problem's on FM btw. I can't really conceive of listning to anything else.

And the fridge is grounded correctly too.

:(

flyblue
29th Sep 2005, 06:29
Mr Bre,
thank you for your help. I listen to AM because I can't get it on FM here :{
Pour écouter France Info ŕ l'étranger, une seule solution : Internet ! Vous pouvez écouter la radio en direct ou ŕ la carte sur le site de France Info.

BTW I don't find it boring, I can stand 1 hour, 1 hour 1/2 ;)

RJM
29th Sep 2005, 10:03
Serves you right, I'm afraid.

Now if you'd bought a proper new radio in a box from a reputable dealer instead of this 'under-the-cabinet' one...

'Ullo, 'ullo - a new fridge. Got a receipt for this little beauty have we sir?

:cool:

Farrell
29th Sep 2005, 10:26
Somewhere on the back of said 'under the cabinet' radio, you might find an FM aerial connection.

If it's there, it'll probably be the old coaxial type.

Just grab yourself a metre of 0.5 bellwire and run it from the inside coax upwards - should do the trick

or even better, if there is a connection on the back, buy one of those square black FM aerials that you used to get with hifis - you can still buy them in Currys or even Virgin I think

colmac747
29th Sep 2005, 12:11
Stuff a bit of rolled up kitchen foil in the back of the thing! Worked for me:ok:

Onan the Clumsy
29th Sep 2005, 12:20
no external antenna connection :(

I thought about silver paper, I'll give it a try.

RJM
29th Sep 2005, 13:07
Very professional advice! I just put about a 3 turn loose roll of al foil behind the radio of my antique souhd system and it solved a buzz I think came from the replacement TV. Worked a treat!:ok:

flyblue
29th Sep 2005, 13:11
Holy cow! I just understood what that foil thingy I found on the radio of my house in Paris after my father visited was for :ooh:

DX Wombat
29th Sep 2005, 13:35
Is the radio plugged into one side of a double socket which it shares with the fridge? If so, try plugging it into a different socket. You don't need to move the radio, just relocate the plug.

seacue
29th Sep 2005, 16:22
I rether doubt the grounding the 'fridge would have much effect at 100 MHz / 3 meters (FM) since the power cord is a large fraction of a wavelength long.

The noise might be conducted on the power wiring. Places like (gasp) Radio Shack sells (for too much money) ferrite thingies that you can clamp around the power cord right where it comes out of the 'fridge. They make the 100 MHz energy think that there's 50 or 100 ohms or so of resistance in series with the wires that go through the ferrite. You want it right at the 'fridge so the isn't wire to radiate before the "filter". Cascading units might help if you note an improvement with just one. These clamp-on ferrites are also available at stores selling to radio hams.

Similarly, your radio is almost surely using its power cord as its antenna. An ideal way of getting interference conducted on the mains wiring. You could try a similar filter right at the mains plug - not - at the radio end of its power cord - since you need the cord as the antenna / aerial but you want to strip off noise coming on the power line.

I'd think treating the 'fridge end would have the best chance of being effective.

Hope this helps, but these magic ferrite things have only limited effectiveness. You'll note them as blobs on computer data cables to meet the interference rules.

sc

seacue
29th Sep 2005, 18:07
Mr. B. Reach,

I presume you want to listen to marine radio on 155-170 MHz.

If, as you indicate, the other poeple in your building are just listeners, you probably won't receive interference from them. There is a proviso that their receivers may have too much escaping from their local oscillators. The would be roughly 45 MHz above the TV channel they are viewing or 10.7 MHz above the FM station they are receiving. Superficially it doesn't look as though any of those should be a problem in Brazil.

The cell phones are on 900-&-some MHz and much higher. The old 150 MHz analog phone service probably went away long ago. That would have to be poor design on the part of your marine radio if the cell-phone system were to interfere - and easy to filter out. There even could be mixing in your receiver's front end between two cell-phone transmitters which could produce spurious signals on the marine frequencies. Again, fairly easy to filter out.

At least that's my guess. I'm available for an on-the-site inspection trip should you require one. Rio during the northern winter would be nice.

sc

Mr. ONC,

You really should get after the manufacturer of the \'fridge. It may well be exceeding the interference limits set by the FCC.

If you are having problems, others will also. Start with the \'fridge manufacturer, then do a Google Groups search for the type number and "interference".

Finally Ed Hare, the RFI person at the national ham outfit, the ARRL, will have "contacts" and might be interested because of the probable effect on ham reception. Any box which radiates is also probably poorly protected against interference from nearby transmitters which could scramble its operation.

sc

broadreach
1st Oct 2005, 13:00
Many thanks, Seacue!
It's actually an AIS receiver station, monitoring ship movements, speed and heading.

seacue
1st Oct 2005, 15:03
Mr. Reach,

I learned something from your question. I was unaware of AIS. A little Google search showed that they use VHF channels 87B and 88B so my suggests are appropriate. Do you have software for a PC which interprets the transmissions? What 9600 baud modems are used?

A similar system is in at least experimental use for aircraft in Alaska where distances are large and radar coverage incomplete. It can present the pilot with a "pseudo-radar" picture of all nearby planes so-equiped.

seacue

broadreach
2nd Oct 2005, 14:51
Yes, Seacue, got all that. No need for a PC, the signals go straight into a black box connected to a modem with a fixed IP adress. It's the first of what will eventually be 20-25 such installations in other ports. The learning curve's been a bit steep!
Tks,
broadreach

seacue
2nd Oct 2005, 18:02
Ah, Mr Broadreach, you must be doing it professionally.

It seemed like an interesting system and I though I might collect the bits (oops pun) gear and go over to the Chesapeake some day and see what I could see displayed on a laptop.

I guess I could figure it out for myself if I could find the standard.

tnx

seacue

Beg your pardon, Onan, for highjacking your thread.

Jerricho
2nd Oct 2005, 18:07
Believe me, hijacking Onan's threads is never something you need to apologise for :E :p