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

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?

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??

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...

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

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

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?

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?)?

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

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?

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?
Right! Overall net gain of 2 - 2.5dB

Assuming the antennas are positioned in a complementary fashion, the cables from each to the splitter are identical type/length, and all of the other bits of fine print are adhered to. :)

But, yes, that is exactly the idea.
I use a splitter just like that here on my dual-PR8800 array, for example.

Right! Overall net gain of 2 - 2.5dB

Assuming the antennas are positioned in a complementary fashion, the cables from each to the splitter are identical type/length, and all of the other bits of fine print are adhered to. :)

But, yes, that is exactly the idea.
I use a splitter just like that here on my dual-PR8800 array, for example.
Would this (stacking 2 antennas) be better than using a pre-amp to pick up weak signals? I'm a little leery to use a pre-amp which might knock out my very strong/very close signals.

I use a splitter just like that here on my dual-PR8800 array, for example.
Note that there may be an even better way to combine two antennas than the reversed-splitter method, though.

For really weak stations, it is important to combine the signals as much as possible *before* any loss-inducing components, so that the weak station has a better chance of not vanishing below the noise floor before it can be amplified.

A big (HUGE) source of added noise can be the 300:75ohm balun device. Those vary from 0.75dB to as much as 5dB of added noise (or effective loss of signal).

So if two antennas can be combined *before* the balun, rather than after a pair (one each) of baluns, the result could be even better for reception of a really weak station.

That's a theory I'm going to put into practice here once the weather warms up.

Our really weak station is WNPI-DT PBS from Norwood, 75 miles away over two blocking ranges of hills. It's a miracle of modern electronics that we even get it here at all, but the margin is tiny -- a difference of 0.2dB and it's gone again.

So I'll be climbing the tower, and redoing the antenna feed to combine the two PR8800 antennas with a direct feedline (simple wires, in a particular geometry) *before* a single balun, rather than after the two existing individual baluns. Calculations suggest that this will gain perhaps 1dB or so, quite significant in this situation.

I will also install a home made coax-loop balun (0.5dB insertion loss) in place of the commerical balun (loss unknown), to perhaps gain another 0.5-3dB or so.

Cheers

Would this (stacking 2 antennas) be better than using a pre-amp to pick up weak signals? I'm a little leery to use a pre-amp which might knock out my very strong/very close signals.
If your setup needs a boost, go for the pre-amp first. Combining two antennas is tricky, the result is bulky and fragile, and the gain from doing so is small.

My big setup has a very good (0.4dB NF) pre-amp immediately after the two antennas are combined.

There are lots of other threads here about pre-amps.

I define a good pre-amp as one with a noise factor (NF) of less than 2.5dB for UHF frequencies. My experience has been that a good pre-amp will always help if one is having reception difficulties, and a very good one (less than 1dB NF) doubly so!

The reason it helps, is that the pre-amp built into your tuner (TV, DVR, or PC) probably has a NF of 5-6dB. So amplifying the signal before it gets there will replace the tuner's NF figure with that of the external pre-amp, gaining 3-5dB for you without the need for a larger antenna.

Plus, the amplification boost it provides (mostly unimportant beyond the first 12dB or so) will help overcome other losses between the antenna and the tuner.

Cheers

If your setup needs a boost, go for the pre-amp first. Combining two antennas is tricky, the result is bulky and fragile, and the gain from doing so is small.

My big setup has a very good (0.4dB NF) pre-amp immediately after the two antennas are combined.

There are lots of other threads here about pre-amps.

I define a good pre-amp as one with a noise factor (NF) of less than 2.5dB for UHF frequencies. My experience has been that a good pre-amp will always help if one is having reception difficulties, and a very good one (less than 1dB NF) doubly so!

The reason it helps, is that the pre-amp built into your tuner (TV, DVR, or PC) probably has a NF of 5-6dB. So amplifying the signal before it gets there will replace the tuner's NF figure with that of the external pre-amp, gaining 3-5dB for you without the need for a larger antenna.

Plus, the amplification boost it provides (mostly unimportant beyond the first 12dB or so) will help overcome other losses between the antenna and the tuner.

Cheers
mlord:

I will probably use a pre-amp, but my fear is that it will knock out my very close (2.5 miles) signals- any suggestions?

Well, that's one of the perils of trying to pull in a weak distant station in the presence of VERY strong local stations.

The suggestion I have, is to try it. If it does turn out to be an issue, then consider two antennas (and an A-B switch): one for the strong local stuff, and another for the pre-amp and weak distant stations.

And/or use notch filters to weaken the effect of the strong locals.

Cheers

mlord:

are notch filters the same as attenutators?

If I use a notch filter on the very strong signal (chch) will it interfere with the weak signal (wutv) I'm trying to get?

RE the two antenna set up, I was just going to go with one antenna with a pre-amp and aim it directly at my weak signal (wutv 47 miles away). CHCH is the very close signal, but it is more east-north-east, while wutv is more east-south-east.

are notch filters the same as attenutators?
Similar, except they are channel specific. Eg. designed to attenuate, say, VHF 11, to reduce interference with VHF 9 or 13.

If I use a notch filter on the very strong signal (chch) will it interfere with the weak signal (wutv) I'm trying to get?
Dunno. What (real) channels are those?

Similar, except they are channel specific. Eg. designed to attenuate, say, VHF 11, to reduce interference with VHF 9 or 13.


Dunno. What (real) channels are those?
chch is 11 analog, 18.1 digital (might be 11.1 after 2011), wutv is 14.1 digital.

chch is 11 analog, 18.1 digital (might be 11.1 after 2011), wutv is 14.1 digital.
But are those the *real* channel numbers?

As opposed to the fake/virtual numbers the industry uses to confuse everyone. I'm totally convinced that the cable companies sabotaged OTA DTV by getting that stupid "feature" added to the spec. Ugh.