Splitters, Attenuators, Filters, Diplexers, Other Signal Gear

[roger1818]

^^^You can put a splitter between the pre-amp and the power source as long as it is a DC power passing splitter. Optimally it will only pass power on one port. If it does pass on all ports, you should put a DC block on the other port(s).

[leszek]

Can I put a splitter between the Pre-amp and the powersource??

Yes, there are splitters with one DC power pass port.

[gcd0865]

Hi All - looking for some filtering/amplifying opinions from the group. Using a CM4228A antenna on a rotor outside on the chimney (currently without any amplifier), a number of long-range stations come in at night but are unreliable during the day. Here's my TVFool report:

http://www.tvfool.com/?option=com_wr...d5bc4d28e6c09c

Focusing on the south-southwesterly direction for the moment, most of the local tv towers (and FM towers) are 8.9 to 11.3 miles in that direction. When "aiming through" that area, WTVG-13, WTOL-11 and WGTE-29 all come in after about mid-evening, but are unreliable during the day. WNWO-49 and WUPW-46 have never appeared once, not even on good tropo evenings.

Knowing full well that I might be too close to my locals for any amplifier, I picked up a Winegard HDP-269, but have not gone up on the chimney to try it yet. If the HDP-269 does indeed overload (as I think it might), I was considering a few options:

(1) add in a low-side terminated HLSJ or other FM filter before the amplifier to remove the local FM farm signals from the mix

(2) add in a 174-698 MHz (passband?) filter before the amplifier to remove FM and cell signals from the mix

(3) add a special filter (with or without (1) or (2) above) to remove local UHF channels 41-45 before the amplifier (which may be hampering WNWO-49 and WUPW-46) and just use my separate attic antenna (which is already on a switch at the tv) for those local channels

I'd very much appreciate any opinions on whether reception of those distant stations at 188-192 degrees true can be possible from my location. Thanks in advance for your comments.

[jflarin]

Originally Posted by Jakeman3

When the house was contructed, we never put an outlet in the 2nd floor bedroom and I would like to add one here - the question is how, and I'm looking for any idea's / suggestions.

[...]

Another idea I have, and I'm looking for an answer if it's possible... is to split the downlead coming down the tower (before the pre-amp power source) and run the line outside...right into the second floor room??? Can I put a splitter between the Pre-amp and the powersource??

I don't think it is a good idea to take an antenna signal and go directly to a TV on the second floor room because of grounding. You can check local regulation and/or grounding forum, but as far as I know, the cable must go down to close to the soil, then pass through a grounding block (attached to a grounding rod) and then the TV cable can go inside de house. Attaching a splitter before the grounding block beats the purpose of the grounding block. If lightning strikes the antenna, electronics blowout all around the house (lightning can go through the TV back to the 120V of a house and blow up everything in the house...) and there is a proper grounding block, the insurance will pay for the damaged electronics. If the lightning strikes, there is no proper ground and electronics blow in the house, the insurance can say that the source of the problem is the missing ground and refuse to pay (of course, YMMV...)

What I found to be a good way to fish cable in the house is to use recessed lights ( is the wording ok?) You can remove those and access the ceiling between the first and second floor. It works with speakers on ceiling also. Whenever you succeed passing a fish wire between 2 spots, put a wire string in there, that you can reuse the next time you have a new cable to pass.

If you can go in the attic, you can find a vent pipe. If you can follow that pipe down to basement, then you can run the wire in the attic and then go down in the room you want to reach.

Also, you can use closet to run wire from floor to floor. A cable in the back of a closet isn't so bad.

Good luck!

jf

[stampeder]

Originally Posted by jflarin

Attaching a splitter before the grounding block beats the purpose of the grounding block.

Assuming that everything below that first split (the downward side, not the antenna on the upward side) is grounded according to proper standards the grounding would still be available to that first split via the outer conductor of the coax cable and the outer metal shell of the splitter, but if this isn't ensured by proper planning and connections it could result in a very bad situation.

Also everyone as you string a home with multiple OTA feeds please be sure to read through the official Digital Home Grounding Info & Standards: OTA/Dish/CATV/Telecom thread frist for everything you will ever need to know about that extremely important topic.

[roger1818]

You could always use the splitter as a grounding block (most splitters have a ground screw). You will want to put an separate gas discharge surge protector between the splitter and the antenna.

[threeflags]

I'm thinking of adding a set of rabbit ears to supplement my reception of VHF (currently setup is a AD DB4e). My rabbit ears terminate to 2 spade connectors which I believe is 300 Ohms ... rooting through my odds and ends I came across a coupler that is best described as having 2 screws (for 300 ohms) and a male coaxial plug (75 ohms). It's definately not a balun. So my question is, what's the better way to fed in my VHF signals? Use this simple "converter" or use a balun? Thanks.

[roger1818]

threeflags, does it look like this?



What makes you think it isn't a balun? The biggest issue I have with this type of balun is the push on connector. It also may not perform very well.

One option is to take apart the rabbit ears, unsolder the 300ohm lead, solder the 300 ohm end of a good quality balun directly to the elements and then put everything back together again. This may be easier with some antennas than others. It does make replacing the balun more of a challenge however.

[ADTech]

Parts from our C2 VHF reflector kit will bolt right onto a DB4e and will provide a decent short-medium range VHF enhancement.

The device roger1818 pictured definitely is a balun (matching transformer) intended for indoor-only usage.

[threeflags]

Thanks lads ... that's exactly what I have. I always thought a balun would be bigger than that. I guess I'm thinking of baluns like those bullet shaped ones.

Currently the setup is in the attic so weather won't be much of a problem.

Anyone know what that type of balun is called? 300 to 75 ohms push on?

[roger1818]

I don't know if it has an official name. I would call it something like a "screw terminal to male F connector balun," but "push on balun" is also good.

[gculley]

I’d appreciate some advice. I erected a new antenna last weekend. I’m using a CM4228HD with a CM7777 preamp up about 30ft.

I live in the Waterloo area and we are located about 8 miles from the CKCO tower (I can see it in the distance) and the TVFool report shows its NM as +60db.

I seem to be getting channels fine, but I notice on other “empty” high-VHF channels (ex. channels 7, 8 and 12) that my signal strength is registering as around 75%, even though there is no station on those frequencies. I’m guessing that the powerful local station is accounting for this.

I also notice that CHCH Hamilton (which is 67 degrees off-axis from CKCO) sometimes seems to struggle to get a digital lock (once it locks I get a good signal quality reading). I’m suspecting that again our local station may be accounting for this, but can’t be sure because MediaPortal can’t scan it due to some non-ATSC standard the station is using (I need to enter it manually as a channel).

CFTO Toronto only comes in during the evening, though during the day it has decent signal strength but a lousy signal quality.

Should I be looking at possibly purchasing a notch filter to reduce the signal strength of CKCO (Channel 13)? Would this hurt/help reception of other channels (I know that there is insertion loss, but if it lowers overall noise it may be worth it)? Is it possibly not needed because of the CM7777 or could it be possibly causing the CM7777 to throttle its gain on all frequencies?

[nbound-au]

Sounds like you need to notch back thats station and by a decent amount, the notch filter will need to be installed between the antenna and pre-amp, not after. If your suspicisions are correct, then there will be a much better S/N ratio after doing so, which will cause marginal stations to be more reliable, as over amplifying will fill nearby frequencies with noise.

[majortom]

u could also try not amplifying the VHF band, using seperate uhf / vhf antennas.
Especially since a 4228 isn't a VHF antenna in the first place.
In addition you may want to try setting the CM7777 to separate inputs (instead of combined uhf/vhf), and leave the VHF input port empty.
I don't use a CM7777 so not sure if that model does that or not, the instruction sheet should spell it out if it does. Can't help much more there.

uhf -> preamp-> diplexor uhf port 
                                       ------------->downlead vhf/uhf 
vhf ----------> diplexor vhf port

[nbound-au]

Also a good idea, though may lose some stations (which you are unlikely to be receiving now due to noise anyway) [basically its a case of will the better S/N counteract the lower overall signal strength]. Whether there are any stations in that marginal category anyway I couldnt say as Im unfamiliar with the area.