Runboard.com
You're welcome.
Community logo


runboard.com       Sign up (learn about it) | Sign in (lost password?)


 
yamanx1 Profile
Live feed
Blog
Friends
Miscellaneous info

Head Honcho
Global user

Registered: 09-2007
Location: In a world of my own
Posts: 4757
Karma: 18 (+19/-1)
Reply | Quote
TVI


I know everyone who's into any kind of distance radio has suffered with causing television interferance at one time or another.

Of course its not your own telly thats the problem but all the neighbours, particularly if your freebanding and operating illegally. It could be a disaster waiting to happen.

Even though statistics are in our favour with very few prosecutions, miniscual numbers frankly get nicked or even investigated. In this world maniac psycopaths, there are far bigger fish to fry than a CBer, or some illegal radio transmissions on some long forgotten disused fequency.

Never-the-less, if you persistantly cause interferance to others and particularly the great god television you may well be asking for trouble. And even if you're not worried about the long arm of the law, its just common courtisity to others who may be pursuing their own interests.

I have made just about every effort I can to not cause TVI, if you look at photo's of my shack you will see filters and ferrite rings all over the shop. But last night I found I was causing TVI whilst using 86mb. Its the only band that seems to cause it (?).

I have to figure a way of stopping it, as I do not want to stop using that band. If you have any further suggestions please feel free to help here emoticon

I will use a second ferrite clamp on the feed line. Also I havent ground the radio properly and the ATU needs grounding as well. Thats a couple of things at least.

---

By all means think yourself big, but never think others small.... R.F.Scott
16/Oct/2007, 8:22 am Link to this post Send Email to yamanx1   Send PM to yamanx1
 
agradinho Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 10-2007
Posts: 8
Karma: 0 (+0/-0)
Reply | Quote
Re: TVI


Hi mate, do you know a good website/s to give info on tvi reduction for 11metres.
How do you use ferrites?
Regards
Steve
5/Nov/2007, 7:33 pm Link to this post Send Email to agradinho   Send PM to agradinho
 
yamanx1 Profile
Live feed
Blog
Friends
Miscellaneous info

Head Honcho
Global user

Registered: 09-2007
Location: In a world of my own
Posts: 4757
Karma: 18 (+19/-1)
Reply | Quote
Re: TVI


Hi Steve,

Have you got a TVI problem?

There are many sites, all have slightly differeing ideas on the subject. Just google. There is one reoccurring theme, and that is there is no cure. Not a one stop shop anyway.

It can be caused by any number of things and sometimes its the equipment thats being interfered thats faulty or poor condition and you cant do anything about that if its not yours.

Obvious things to try first are ferrite rings or clip on blocks, these just clip on exisiting coax or cables if you look at the image of my shack in the pictures section you will loads of these clipped on coax and power leads. For me they made no difference at all,

Of course you will need a low pass filter, get a good one from a ham shop Kenwood or Yaesu. For me? This made no difference.

Use a good coax, I used RG213, its stiff and difficult to use, and fairly expensive. For me? Nope no difference.

Thern ground the radio, do a proper job. Bang some copper pipe into the ground outside about 4 foot deep, attached a heavy cable to it and the other end to your radio. For me? Well some difference, this was the most effective thing that worked. But it may not have worked on its own and it may be the other things were also required.

In addition, I put choke on the coax (Wind coils about 6" dia) and changed the electrical cable to my shack to SY screened cable.

Ultimately I had to move the antenna to a different location and reduce power.

Oh! nd probably most important the SWR has to be pretty much bang on.

If I can help further let me know, I'll do my best emoticon

---

By all means think yourself big, but never think others small.... R.F.Scott
6/Nov/2007, 11:09 am Link to this post Send Email to yamanx1   Send PM to yamanx1
 
michael1006 Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 11-2007
Posts: 8
Karma: 0 (+0/-0)
Reply | Quote
Re: TVI


Hi Yamanx1 glad to be here and take part but can I urgently bring something important to your attention?

 in your last post you mentioned earthing using copper piping

  quote "Thern ground the radio, do a proper job. Bang some copper pipe into the ground outside about 4 foot deep, attached a heavy cable to it and the other end to your radio. For me? Well some difference, this was the most effective thing that worked. But it may not have worked on its own and it may be the other things were also required"

 Can I say that this information is lethal to say the least. Before you embark on earthing your equipment to the ground ( other than the normal electrical earth in the wall socket)you need to know what earthing system your house uses. If it is PME then what you described is extremely dangerous. under certain circumstances you could end up with different potentials across the PME and non-PME earth system resulting in a serious electrical shock and death.

You simply cannot use different earthing systems on any equipment and for you to use the "earth rod" system you would need to take all your equipment off the house earthing system ( which is unwise unless you have the tech know how ) if it is PME or alternatively you would need to bond your ground rod to the earth system in the house using at least 10mm2 earth wire and even earth spikes have their regulations.

 If you have a TT system you will be fine in what you are doing. Michael

Last edited by michael1006, 19/Nov/2007, 3:23 pm
19/Nov/2007, 2:52 pm Link to this post Send Email to michael1006   Send PM to michael1006
 
yamanx1 Profile
Live feed
Blog
Friends
Miscellaneous info

Head Honcho
Global user

Registered: 09-2007
Location: In a world of my own
Posts: 4757
Karma: 18 (+19/-1)
Reply | Quote
Re: TVI


Crikey, well thanks for that and welcome to the site.

Ok, I need to backtrack on this then and do some research, this is not the only place I've posted this information so I'd better do some warning.

How can I tell which earthing system I have?

What would be the alternative method of earthing the radio?

Thanks for your help.

Dave 26fb001

---

By all means think yourself big, but never think others small.... R.F.Scott
19/Nov/2007, 4:32 pm Link to this post Send Email to yamanx1   Send PM to yamanx1
 
michael1006 Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 11-2007
Posts: 8
Karma: 0 (+0/-0)
Reply | Quote
Re: TVI


Hi Dave , there is usually a label fixed on the protection chamber of the cut out, thats where the mains cable coming in from the street goes into your 80/100 amp main fuse. I have heard of instances of sparks putting them on when its not been a PME system and vice versa so I wouldnt rely on that. There is simple ways to check but I dont want anyone going in search of the answer so if you want to know the correct answer I would suggest contacting your Elec. Company but if you have any doubts whatsoever, presume it is PME and then you wont have any problems


Now that said and done, done go ripping all your set up out the wall, I didnt mean to shock and awe you but I thought I should put you right when your giving others advice if you dont know what earth system they have.

If you think that your interference was travelling through the 230v system, why not use 12v batteries and completely disconnect from the mains and you can be sure you wont be causing TVI by that means. I presume you are using low pass filters inline and ferrite rings/beads in your wiring to make a choke.


you asked about best way of earthing your radio, if its homebase (230V) it will be utilising your house earthing system.

One final point lots of people get confused with RF earth and safety earth and i am just wondering which ground you were referring to now.


There is many ways and theories about earthing whether it be RF or surge protection, my postings were referring to earth protection for your equipment and not RF.



However a good safety earth maybe a good RF earth in certain circumstances.
19/Nov/2007, 6:58 pm Link to this post Send Email to michael1006   Send PM to michael1006
 
26fb139 Profile
Live feed
Blog
Friends
Miscellaneous info

DX-pert
Global user

Registered: 01-2008
Location: Dudley west mids
Posts: 1274
Karma: 8 (+8/-0)
Reply | Quote
Re: TVI


how do find out what earthing system your house as??????
put a earth stake in my garden years ago ,comes off atu .also got earthing/lightenig conductor off ariels/mast to the stake. keith 139

---
139 in any GOOD group??
8/Jan/2008, 10:38 am Link to this post Send Email to 26fb139   Send PM to 26fb139
 


Add a reply





You are not logged in (login)