NVIS equipment

[Martin200261]

(14 July 2012, 09:08)Paul Wrote: Interference with: Domestic TV, HIfi's, Domestic radios. etc.

Old time CB'ers will know the effects of too much power through badly tuned aerials causing "squiggly lines" on a TV set and bursts of noise on the Hi-Fi.
Some city dwellers will also have also had the happy pleasure of the same from taxi radios, etc.
The problem is it can be caused by all types of radio transmission and, in a built up area, it doesn't take much power to cause problems with your next door neighbour.
Most stuff you buy today like TV's, Hi Fi's, etc is rubbish at keeping interference out and even crackly light switches can cause flickers on your TV and crackles through the Hi Fi. Technology advances and plastics in everything has actually increased this problem.

It follows that experimenting with long wire aerials can attract the wrong sort of attention. Long wires are occasionly difficult to tune in BUT if you try and take short cuts by using an aerial tuning unit BEWARE.

Although an ATU can electrically tune an aerial into a safe load for a transmitter, a rubbish aerial will always be a rubbish aerial and that will cause interference.

It can in extreme situations (and a prat of a neighbour complaining) lead to TPTB arriving at your door with a search warrant. They can (and do) seize anything they like if they think it pertinent to the problem be that legal gear or otherwise.

So, knowing that no one on the forum would ever think of setting up a transmitter without the proper licence and training, folk thinking of setting up NVIS or even CB sets must be careful.

IF your neighbour is an idiot, argumentative, or just a complete prat. My advice is:-

Only install covert aerials.

Keep power levels down, RIGHT down especially during intellectual TV programs like East Enders or Britians Got talent.

Or wait till they have gone down to the pub or Bingo before transmitting.

Avoid using types of transmission that can easily cause interference like AM, SSB, and especially morse when the neighbours will be watching the TV.

p.s. All this applies to CB'ers, freebanders, as well as 'knowedgable' hams.

Paul

The TV interference isn't quite as much of a problem nowadays, eu regs have made manufacturers improve their designs so that they are not quite so susceptible and of course digital tv helps a bit too. Though watch out if you are in a poor reception area with everyone using signal boosters - you can cause a blackout with very little power!

Antennas can be very discrete, a bit of cable tacked to the top of a garden fence or a dipole attached to the washing line - almost invisble.

---

So who's up for learning morse?

I've started, there are several tutor programmes available.

The huge benefit of morse is the ability to get long distance with very little power, I frequently hear automatic beacons from the states operating on as little as 1W whilst I can struggle to pick somebody up on SSB using 50w from 20 miles away if conditions aren't right.

Low powered sets for morse can be relatively cheap or even home made while SSB sets cost quite serious money.

I'm going to build a simple cw transceiver and will let you know how I get on with it.

Cheers,
Martin