Antenna power injector and splitter

I have a couple of Winegard powered antennas. The power injector has
developed an intermittent failure, so I took it apart to see what was
going on.

It looks like there is an invisible break in the circuit somewhere. I
could try to fix it, or I could build a new one and address some other
issues.

So...

The injector consists of two RF jacks, one for the TV and one for the
antenna.

The power portion of the injector looks really simple. It's a transformer
with a diode, a cap, and a resistor in series going to the antenna jack.

There is a 'mystery component' that connects the TV jack to the antenna
jack. It must be some sort of isolator so that the power doesn't get to
the antenna. Physically it looks like a tiny 1/2 length 1/8 watt
resistor. I'm guessing it's a capacitor that would pass the
RF frequency but not the DC power. It's too tiny to make out any
lettering or marking.

Anyone know what value/type this cap would be?

Second, I have two antennas and two TVs. Right now, I have both antennas
going to a splitter in reverse, combining the two signals, then through an
amp, then back to a splitter. (The two antennas in parallel work well
because of my fairly unique location.)

There is also a ground block.

All that makes for a bit of a mess, and I have problems with the splitters
and signal strength, as the amp I have now is after the ground block and
the first splitter.

I'd like to power the antennas and deal with the amplified signal. The
powered antennas provide 20 dB boost, which overpowers the tuners. I need
about 6-12 dB boost, so I'd like to have attenuation capability.

I'd like to eliminate all of that, and build a single box that would allow

1. Power injection to the antennas
2. Combine 2 antenna signals
3. split two TV singals
4. Provide a ground block
5. Provide attenuation if necessary.

I've googled a bit but most of the hits are for wifi and gps, which
doesn't really apply.....

 

dunno about that one, but ceramics are good at RF,
anything around 10nF should work fine.
(I see one like that in a different power injector)

start with a weatherproof alloy box...



a regular splitter will pass power all ways.

Bye.
Jasen

 

V Sat, 07 Apr 2007 08:31:45 +0000, jasen napsal(a):

Do you know what's in one of those?

The only thing I've seen is a guide on how to wrap some wire around one of
those torroid magnets. It sounds like it would work - but the cheapie
splitters I see don't have magnets.

How do they split?

 

the two I've looked inside the the centre conductor passing through some
ferrite bead transfromers and a capacitor from one of the intermediate
connections to ground, hmm, I guess passing too much current through one of
these could saturate the core....

probably what went wrong with the one I injector I built built a couple of
decades ago (phillips OM350 datasheet)

poorly I expect.

Do they have resistors?

Bye.
Jasen