Splitters, Attenuators, Filters, Diplexers, Other Signal Gear

[mlord]

The yagi thread in the antenna R&D section has much better reference links for stacking.

This one, Stacking, Phasing, and Matching Yagis explains the concepts in considerable detail. The article is about yagis, but the stacking principles can be applied to other designs.

Cheers

[roger1818]

Originally Posted by mlord

The yagi thread in the antenna R&D section has much better reference links for stacking.

This one, Stacking, Phasing, and Matching Yagis explains the concepts in considerable detail. The article is about yagis, but the stacking principles can be applied to other designs.

Interesting article mlord, although it is focused on stacking antennas pointed in the same direction for the purpose of increasing gain. Things are quite different when the antennas are pointed in different directions like cigar7 is wanting to do.

[rlegault]

Sorry if this question is stupid.

So Lets say I have two diplexers that do NOT block DC. I connect them in the normal way and do not have a preamp on my antenna. Will the DC voltage from the receiver act as a preamp on the antenna? Or what will this do to the antenna is anything?

[mlord]

Originally Posted by roger1818

Interesting article mlord, although it is focused on stacking antennas pointed in the same direction for the purpose of increasing gain. Things are quite different when the antennas are pointed in different directions like cigar7 is wanting to do.

Ah. I missed that, thanks.

Elsewhere in that same yagi thread, is a link (which I've lost track of now) that dealt with that situation as well. It turns out to use the exact same math, and suggests that for UHF *especially*, it is important to keep the other antennas outside of the receive aperature.

Or worst case, outside of 1/2 the receive aperature. So, same calculations apply.

Cheers

[Techluvr]

Originally Posted by rlegault

Sorry if this question is stupid.

So Lets say I have two diplexers that do NOT block DC. I connect them in the normal way and do not have a preamp on my antenna. Will the DC voltage from the receiver act as a preamp on the antenna? Or what will this do to the antenna is anything?

The simple presence of a DC voltage does not amplify an RF signal. What are you diplexing? If you're connecting a satellite dish and an OTA antenna to the diplexer, then you don't want the DC from the satellite receiver to go up the antenna. The satellite receiver uses a DC voltage to switch the polarity of the LNA on the dish; I don't know of any other type of receiver that outputs DC on its RF input.

[rlegault]

Thanks, I wasn't planning on doing that, was just curious. And yes, diplxing satellite and OTA. Just the part in the house.

[Techluvr]

Originally Posted by rlegault

Thanks, I wasn't planning on doing that, was just curious. And yes, diplxing satellite. Just the part in the house.

O.K. now I'm curious. What are you diplexing the satellite signal with?

[goforit]

I'm 2.6 miles west of the chch tower.

I would like to use a pre-amp to get a better lock on wutv which is 47 miles east.

I will aim directly at the GI towers which is a little south (in aiming) than the chch tower.

Do I need to use an attenuator to stop the overload to my tuner from the chch signal? Where do I place it? Will it lessen the signal strength for wutv?

I would like to lock onto wutv, I get it rarely, but with the many pre-amps out there, how does one decide which one to get beyond trial and error?


I want to run a 4221HD with a pre-amp, aimed at the wutv tower, getting chch on the side as well as tor and south buf, which is never a problem.

I want a pre-amp that will help get wutv, but I fear that chch will kill my tuner, any suggestions? cm 7777, cm 7778??

[balm]

Does anyone know if it's possible to make your own (low loss) splitter...

Also, apart from using the signal strength meter on the TV, is there another external meter,instrument, or method I can use to measure signal strength and noise levels etc...

[bowshock2]

i dont use any hifi channel master stuff. just low quality $30 4 bay bowtie antenna. two antenas stacked vertical together with 6 inch apart stacked like two squaures . important to note i did not use any splitter combiner to connect antennas rather. used aluminuim coil and connected the bowties of both antennas and only one coax from first antenna runs to winegard ap 4700 preamp (uhf specific preamp) and goes around 50 ft cable with splitters later.

i get ABC NBC CBS FOX PBS CW23 PBS-TH and all canadian channels

Antenna is installed straight in attic.

no loose RG6 cables all cut for correct length, quality preamp, stacked identical antennas together with one coax only...you get all channels..simple

[mlord]

Originally Posted by balm

Does anyone know if it's possible to make your own (low loss) splitter...

Huh? Just about *any* store-bought splitter ($0.49) is low-loss, so trying to make one won't gain anything over those.

The loss from a splitter is normally about 0.5dB, just from connecting the RG6 to both sides. It's really hard to beat that for low-loss.

The terminology people commonly use here with splitters can be quite misleading, though. People say that a 1:2 splitter has a loss of 3.5dB, for example. That is not at all correct. The loss is only 0.5 dB.

The 3.5dB value comes from the fact that the input has been split into two outputs, each with half the original signal. Half = -3dB. So, add the 0.5dB loss to that, and one gets the 3.5dB number. But one has not lost 3.5dB of signal: it's all still there in the two outputs, minus 0.5dB of true loss.

Cheers

[Techluvr]

Originally Posted by mlord

The terminology people commonly use here with splitters can be quite misleading, though. People say that a 1:2 splitter has a loss of 3.5dB, for example. That is not at all correct. The loss is only 0.5 dB.

I have seen the term "insertion loss". Does that to refer to the loss of signal within a device as opposed to the intrinsic signal decrease caused by splitting?

[goforit]

Originally Posted by bowshock2

i dont use any hifi channel master stuff. just low quality $30 4 bay bowtie antenna. two antenas stacked vertical together with 6 inch apart stacked like two squaures . important to note i did not use any splitter combiner to connect antennas rather. used aluminuim coil and connected the bowties of both antennas and only one coax from first antenna runs to winegard ap 4700 preamp (uhf specific preamp) and goes around 50 ft cable with splitters later.

i get ABC NBC CBS FOX PBS CW23 PBS-TH and all canadian channels

Antenna is installed straight in attic.

no loose RG6 cables all cut for correct length, quality preamp, stacked identical antennas together with one coax only...you get all channels..simple

Can you be more specific about how/where you connected the two antennas (maybe a picture?)?

[mlord]

Originally Posted by Techluvr

I have seen the term "insertion loss". Does that to refer to the loss of signal within a device as opposed to the intrinsic signal decrease caused by splitting?

That's how I normally think of it. Pretty much any passive device will have an insertion loss below 1dB. Anything over that, and there's something else going on.

Cheers

[goforit]

Originally Posted by mlord

Huh? Just about *any* store-bought splitter ($0.49) is low-loss, so trying to make one won't gain anything over those.

The loss from a splitter is normally about 0.5dB, just from connecting the RG6 to both sides. It's really hard to beat that for low-loss.

The terminology people commonly use here with splitters can be quite misleading, though. People say that a 1:2 splitter has a loss of 3.5dB, for example. That is not at all correct. The loss is only 0.5 dB.

The 3.5dB value comes from the fact that the input has been split into two outputs, each with half the original signal. Half = -3dB. So, add the 0.5dB loss to that, and one gets the 3.5dB number. But one has not lost 3.5dB of signal: it's all still there in the two outputs, minus 0.5dB of true loss.

Cheers

So..., if you connect two identical antennas (eg 4221s) with a joiner/reverse splitter, the theortical advantage is a gain of 2 to 3 dbi, but the loss of the splitter is .5 dbi, so an overall gain of about 2 dbi..., is this correct?