RF modulators

snaps

I have been asked to send a DM around a house, what are common RF modulators like? IS the quality as good as an RF output on a sky box?

watty

The Sky box modulators are rubbish.

None are very good. Also of course they wipe out the next lower channel.

I've got better results with a modulator out of scrapped VHS than Sky box. Just add +9V, video and audio. The old kind with brass screw tuning.

No idea how good the packaged up ones are. But most seem to be the same as in a modern VHS or Sky box with a DIP switch to set the channel and a micro to set the frequency via the modulator's I2C connection.

So it's likely to be as good or better. Just remember that they ALL take up next lowest channel and create interference on some other channels and raise general noise level.

Booms

Not strictly related to your question, but Bill Wright has some articles on distributing modulated signals further down this page:

http://www.wrightsaerials.tv/articles/index.shtml

You might find them interesting

watty

This one
http://www.wrightsaerials.tv/articles/whatsat-clear-sky.pdf

Yes. It has filters on the Modulator output. And notches the Modulator channel on the aerial.

Very good

darth_maul

vision modulator
this one is the best within its price range, has adjustable video level. Great little unit

see quote below from bill wright

A modulator accepts baseband video and audio signals and turns them into a TV channel. There are a lot of different types on the market but in my opinion the best for this sort of job is the Vision V40-104. Reasonably priced, this unit is head and shoulders above the rest. It performs immaculately, never drifting off frequency or losing its tuning memory when there’s a power cut (the two main vices of certain other makes), and so far I’ve never had one break down. Astonishingly for a product in this price range it is possible to adjust the audio deviation, input level, and subcarrier frequency. The video carrier frequency can be fine-tuned and the modulation depth adjusted. Very conveniently the RF output level can be adjusted up to 25dBmV, so there's no need for a pre-amplifier before the channel filter. I usually set the modulator output to about 20dBmV, which means that I can use the variable attenuator in the channel filter unit for a small amount of final adjustment.

pelisor2000

snaps wrote: »

I have been asked to send a DM around a house, what are common RF modulators like? IS the quality as good as an RF output on a sky box?

i connect my DM to 3 more tv's true a modulator..
http://www.triax.co.uk/Products/Domestic%20Distribution%20Products/Tri-Link%20Kit.aspx?productId=%7B86F5253D-76C3-41B6-8BEA-008A662D5C2B%7D&Tab=0

spongerobinson

as watty said above, you might get decent results from an old vcr if you have one lying around! i have one in my attic that i use to send a spiderbox around the whole house, along with a sky box signal, and an aerial, and reception is perfect in every room. its split to 4 or 5 different points using a powered splitter, a global f140.

something you could try quite easily if you do have a vcr lying around anyway, as alot of people do!

12 element

Alcad do a RF modulator (MD-410) that would be ideal for this kind of job!

snaps

spongerobinson wrote: »

something you could try quite easily if you do have a vcr lying around anyway, as alot of people do!

i never thought of that!

Booms

Okay. I give up. What's a DM? :P

snaps

A make of a satellite box, Dream multimedia, or Dreambox.

Booms

Thanks, I couldn't decide between Doc Martens or DangerMouse.:)

Hope you get sorted okay.

byte

The Doc Martens are only introduced to the satellite hardware when things don't work!

Mind you, the Doc's seldom fix the problem!