car radio antenna ground

[ditchcrawler]

 

Your quite correct from what I read of the post

But I cant see how it would help

[Graham.m]

But I cant see how it would help

 

It would not, the screen is already connected to the radio via the aerial plug plugged into the radio.

[ditchcrawler]

 

It would not, the screen is already connected to the radio via the aerial plug plugged into the radio.

Thanks.

Maybe you can tell me how you would fit a capacitor to this aerial assembly ? http://www.ebay.co.uk/itm/like/270529875421?adgroupid=13585920426&hlpht=true&hlpv=2&rlsatarget=pla-131843268786&adtype=pla&ff3=1&lpid=122&poi=&ul_noapp=true&limghlpsr=true&googleloc=1006886&device=c&chn=ps&campaignid=207297426&crdt=0&ff12=67&ff11=ICEP3.0.0-L&ff14=122&viphx=1&ops=true&ff13=80

Actually probably the easiest way would be to bridge the plastic washer you proposed with a capacitor, that would also save cutting the screening back.

edit

It all gives something to think about.

Edited January 17, 2016 by ditchcrawler

[Graham.m]

Thanks.

Actually probably the easiest way would be to bridge the plastic washer you proposed with a capacitor, that would also save cutting the screening back.

edit

It all gives something to think about.

 

I will leave them to think about it as I am happy the impedance would be fine at normal broadcast frequencies in the UK

[ditchcrawler]

 

I will leave them to think about it as I am happy the impedance would be fine at normal broadcast frequencies in the UK

Its an interest idea, I look forward to actually trying it.

[mickp]

What did they do on reliant robins .im sure i was told they sent a cable down to the chassis but that was hearsay .sending a cable back to earth should work as its taken from the feed point like each leg of a dipole.not connecting the braid would struggle to couple to the shell without help

[Graham.m]

What did they do on reliant robins .im sure i was told they sent a cable down to the chassis but that was hearsay .sending a cable back to earth should work as its taken from the feed point like each leg of a dipole.not connecting the braid would struggle to couple to the shell without help

 

The Reliant Robin was a fibre glass body car. I have never seen a car radio aerial that was a dipole. If it was a dipole there would be no need for either side of the dipole to be earthed to the car chassis.

[mickp]

[bquote name=Graham.m" post="1741397" timestamp="1453067659]

 

Being fibreglass gives the same problem we have with no shell to directly ground..werent dipoles used on window screens years ago ,a little bit like those heated screens you stuck to the rear window

The Reliant Robin was a fibre glass body car. I have never seen a car radio aerial that was a dipole. If it was a dipole there would be no need for either side of the dipole to be earthed to the car chassis.

[ditchcrawler]

 

The Reliant Robin was a fibre glass body car. I have never seen a car radio aerial that was a dipole. If it was a dipole there would be no need for either side of the dipole to be earthed to the car chassis.

Worked with a chap who had one who was a CB fan and he glued a large square of ally on the inside of the roof with the aerial through the centre of it.

[Graham.m]

Being fibreglass gives the same problem we have with no shell to directly ground..werent dipoles used on window screens years ago ,a little bit like those heated screens you stuck to the rear window

 

 

No it is not the same by any means. The boat I believe you are talking about has a steel roof so you connect to the roof steel capacitively. A capacitor allows Radio signal through while blocking DC. Putting the aerial base against the steel with a piece of thin plastic or other thin insulator between them forms a capacitor that lets through the Radio Frequencies and blocks the DC.

 

AS for aerials on windscreens I seem to remember they were a failure because they were directional and therefore the signal varied depending on which way the car was facing.

 

Worked with a chap who had one who was a CB fan and he glued a large square of ally on the inside of the roof with the aerial through the centre of it.

 

Yep to give the aerial a ground plane. More important when transmitting RF than receiving it.

Edited January 17, 2016 by Graham.m

[mickp]

Yes we know about the capacitors mentioned by others much ealier and i will be testing out a few the weekend .dipole only directional slightly when horizontal which is no good for broadcast radio as its vertically polorized .i suppose a car aerial is similar to a dipole but the car is one leg and the aerial is tuther

[Graham.m]

Yes we know about the capacitors mentioned by others much ealier and i will be testing out a few the weekend .dipole only directional slightly when horizontal which is no good for broadcast radio as its vertically polorized .i suppose a car aerial is similar to a dipole but the car is one leg and the aerial is tuther

 

I will leave you to play with capacitors. Car aerials are based on what is called a 1/4 wave.

[ditchcrawler]

All I know is my reception is crap

[Graham.m]

All I know is my reception is crap

 

Make sure all the connections are good and clean and not wet.

 

Is the VHF bad or is it other frequencies?

[ditchcrawler]

 

Make sure all the connections are good and clean and not wet.

 

II have done that

 

Is the VHF bad or is it other frequencies?

 

I only listen to Radio 4 on FM

[nicknorman]

We don't have a radio on the boat, we listen via 3G.

[Graham.m]

 

 

Make sure all the connections are good and clean and not wet.

 

II have done that

 

Is the VHF bad or is it other frequencies?

 

I only listen to Radio 4 on FM

 

 

DC are you live aboard and are you moored next to a hedge?

 

How long has it been like it?

[ditchcrawler]

 

DC are you live aboard and are you moored next to a hedge?

 

No and No

 

How long has it been like it?

Always, some times its OK

Bit like Triggers broom, 2 radios and 3 aerials

Edited January 17, 2016 by ditchcrawler

[Top cat]

Maybe I'm missing something but our Panasonic FM radio at home just has a piece of wire about 4ft long poked into the centre of a coaxial socket. The wire is strung up the wall vertically, gives good enough reception on R4 . And this isn't a Top Cat bodge thats how the radio and aerial were supplied.

So is thats good enough at home why do we need to mess about with ground planes and capacitors? Just run an insulated wire up through the roof as high as you dare. Or is there more to it than that?

 

Top Cat

[ditchcrawler]

Maybe I'm missing something but our Panasonic FM radio at home just has a piece of wire about 4ft long poked into the centre of a coaxial socket. The wire is strung up the wall vertically, gives good enough reception on R4 . And this isn't a Top Cat bodge thats how the radio and aerial were supplied.

So is thats good enough at home why do we need to mess about with ground planes and capacitors? Just run an insulated wire up through the roof as high as you dare. Or is there more to it than that?

 

Top Cat

Actually winding a bit of wire round the aerial often improves things

[Graham.m]

Bit like Triggers broom, 2 radios and 3 aerials

 

Sorry don't understand that

 

This is on the boat ?

 

What sort of interference is it?

 

Is it all day or just in the evening when the lights are on?

Actually winding a bit of wire round the aerial often improves things

 

How old is the aerial?

[Graham.m]

Maybe I'm missing something but our Panasonic FM radio at home just has a piece of wire about 4ft long poked into the centre of a coaxial socket. The wire is strung up the wall vertically, gives good enough reception on R4 . And this isn't a Top Cat bodge thats how the radio and aerial were supplied.

So is thats good enough at home why do we need to mess about with ground planes and capacitors? Just run an insulated wire up through the roof as high as you dare. Or is there more to it than that?

 

Top Cat

 

If you are in an urban area that will probably be OK as the signal strength will be quite high. In rural areas the transmitters tend to be further away. FM (VHF) is basically line of sight, if you can see the transmitter you will receive the signal. It will follow the ground a bit but not as well as Medium wave (MF)

[ditchcrawler]

 

Sorry don't understand that

 

This is on the boat ?

 

What sort of interference is it?

 

Is it all day or just in the evening when the lights are on?

 

How old is the aerial?

Yes its on the boat. in 15 years I have fitted 3 new aerials and 2 new radios, car type radios. Light do effect it but sometimes its bad without them, auto tune finds stations but its just noise. last aerial is about 4 years old.

[Graham.m]

Yes its on the boat. in 15 years I have fitted 3 new aerials and 2 new radios, car type radios. Light do effect it but sometimes its bad without them, auto tune finds stations but its just noise. last aerial is about 4 years old.

 

How is the aerial wired at the moment?

 

When did you last look at the aerial?

 

Is it one off the rubber dumpy jobs?

 

Have you ever checked whether it is getting full volts, radio that is?

Edited January 17, 2016 by Graham.m

[Loafer]

I've long given up with FM/DAB radio on boats. Always disappointed. I use digital telly now, with the screen switched off to save an amp.

 

Why is digital radio on the telly much better than my 'pukkah' FM/DAB receiver?