RF Noise problem

Hi,


Just switch on Ormerod, and kids shouting at me that TV suddenly turns snowy badly, I try to switch on and off my antenna booster, check on RF cables and try to fine tune my TV but can't correct the badly snowy image on the screen , and also white noise from TV's speaker. I gave up and think I might need a new antenna or TV.
After I turned off Ormerod to take out SD card for saving some of my G codes, the TV suddenly turns clear. I can't believe it and I turn on Ormerod again, and TV become snowy again !!

I clamp a few ferrite filter on the power supply output and input without any improvement.


Swap to 12V 30A industrial power supply and everything goes fine !!!!


EDIT: Mine was Alpine 600W



Ew

Edited 1 time(s). Last edit at 01/21/2014 06:43AM by tru168.

Get a satellite subscription! What country are you in? UK terrestrial TV is all digital these days, so RF noise will either not affect it or kill the reception just about completely.

I'm in Malaysia , no digital TV yet :-(

Quote
tru168
I'm in Malaysia , no digital TV yet :-(

Gosh, the Omerod certainly gets around! Digital TV is a mixed blessing - too much commercial temptation to squeeze in more channels by over-compressing to reduce the bit-rate. Plus the general rule is that the more channels you have, the lower the quality of each. The RF noise your Omerod makes is probably more interesting to watch than most of the channels here!

Dmould:

Yeah, Still using analog here, I even built Vacuum Tube amplifier for my Hi Fi system ;-)

Hi.... I won't say that the Ormerod isn't causing your problem but it's unlikely. Here's a possible solution to what ever it is that is causing it.
RF Braid Breaker
Another design

But the easiest and cheapest is the two loops of coax cable tied together (See the picture).
Basically you make two loops of TV coax. Bare the ends to expose the center core. Nibble off a section of the outer insulation
about 2" from the end, then solder the center core to outer braid you've just bared back so it makes a loop.
Use a bit of tape to cover the connection. Then make another loop the same. Then just tape the two loops together.
Your TV signal should be clear as a bell then (hopefully). The two loops form a transformer that allows the TV signal to cross over, but insulates
the TV coax from a direct connection. Then connect it between the TV Ariel socket and the Ariel lead. (You might have to try it at the TV, then the amplifier to see where the interferance is getting in.

The problem you describe with your TV used to be very common due to CB radio interference and the like.
Hope that helps.
Kim

Hi,


As a Ham Radio Operator for years, I should think of that before you mentioned it. Thanks !


Ew

hihihihi

Used to be G7JYT
Now M0GIO....
Nice to meet you Brother...
QRT


Edited 1 time(s). Last edit at 01/21/2014 12:45PM by KimBrown.

See? Repraper's usually share common interest !

73!
9W2ECG

Quote
tru168
See? Repraper's usually share common interest !

73!
9W2ECG

Going back quite a few years - I used to be ZE1FY (later Z21FY). Then Z21FY/MM for 5 years.

Dave
(#106)

Hello Fellow Radio Users

Well I got to the 2E0 was contemplating on going the full hog and get the M0 but wasn't worth while for me due to restrictions where I am located so I won't be able to run the full 400W (if needed) also the extra band or two you get with a M0 didn't really interest me much also wouldn't be able to put up the antennas for half the bands anyway.
Also 50W (max) is fine for my needs at the moment, and I get to make stuff also

Paul

---

RS Ormerod No 436

400 W thats thats a lot of power ! I'm QRP guy and my DIY rig will not more than 5W, FM or SSB.
need big antenna though..

Quote
tru168
400 W thats thats a lot of power ! I'm QRP guy and my DIY rig will not more than 5W, FM or SSB.
need big antenna though..

Well I am using an ICOM IC-746 with the power turned to the minimum (prob about 1 W) and all the people that I talk to can hear me

Paul

---

RS Ormerod No 436

If you want to make a rig for frequencies higher than UHF, you can make quite a powerful transmitter from the parts in a microwave oven ...

Dave

It's nice to see like minded people nattering.... How did the TV interference problem go? fixed??

I still have my Rigs, in a box safe.... I now live surrounded by houses that are higher than me, so daren't go on air.... But one day.
I miss using my Kenwood, but I use the 100Amp 12V power supply allot for different things.
Wish I had this print back in the days where I was building stuff.. I used to hate cutting the holes out for meters etc, now we can just print them...

I might setup a Maritime mobile shack here for the help of it during the summer. It's too cold to go messing with ariels at the moment.

Hi

Yes, problem fixed by just added a line filter on my power supply :-)