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FM splitter or FM tap

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Anonymous
May 9, 2005 4:09:01 PM

Archived from groups: rec.audio.tech (More info?)

Does anyone have a part number and manufacturer name of a TV FM
splitter also known as a tap? I live very close to transmitters and
would like to keep the signals as clean as possible for both my tv and
radio receivers. I have new rooftop antennas and have already replaced
most cable and connectors.
I did some searches and called some distributors but only found general
references. Neither Radio Shack nor Blonder Tongue have this.
Thanks.

More about : splitter tap

Anonymous
May 10, 2005 12:00:09 AM

Archived from groups: rec.audio.tech (More info?)

In article <1115665741.028372.104250@z14g2000cwz.googlegroups.com>,
fohara@san.rr.com wrote:

> Does anyone have a part number and manufacturer name of a TV FM
> splitter also known as a tap? I live very close to transmitters and
> would like to keep the signals as clean as possible for both my tv and
> radio receivers. I have new rooftop antennas and have already replaced
> most cable and connectors.
> I did some searches and called some distributors but only found general
> references. Neither Radio Shack nor Blonder Tongue have this.
> Thanks.

You didn't mention whether you were using twin lead or coax. Assuming
coax, any 75 ohm TV splitter will work just fine; the FM band is just
above channel 6.

Isaac
Anonymous
May 10, 2005 2:35:41 AM

Archived from groups: rec.audio.tech (More info?)

In <1115665741.028372.104250@z14g2000cwz.googlegroups.com>, on 05/09/05

at 12:09 PM, fohara@san.rr.com said:

>Does anyone have a part number and manufacturer name of a TV FM
>splitter also known as a tap? I live very close to transmitters and
>would like to keep the signals as clean as possible for both my tv and
>radio receivers. I have new rooftop antennas and have already replaced
>most cable and connectors.
>I did some searches and called some distributors but only found
>general references. Neither Radio Shack nor Blonder Tongue have this.

Good components and connections are the key. Tap or splitter is not a
"clean" issue.

A "tap" is a variation of a splitter used in large installations with
long runs of wire. In a home with one or a few locations, taps are not
necessary. The overall idea is to give each location approximately the
same signal level.

In a home this is usually done by placing a splitter at a central spot
and running approximately the same length of wire to each location. The
"daisy chain" method of running to the first location, installing a
splitter, then running on to the next location, installing a splitter,
etc. is not a great plan because the guy at the end of the line doesn't
see much signal. If you would use 2-way splitters, for example, half of
the signal stays at the current location and half goes to the next. At
the next location, half stays and half passes on. You can see that the
last man is quite far down and none of the locations see the same
signal level.

A tap is a specialized splitter that breaks out a small fraction of the
signal for it's location and passes the remainder to the next tap along
the line. Running an individual wire to each unit in an apartment
building would consume many times more wire than necessary. One
normally amplifies the signal enough that the last man sees an adequate
signal, then picks taps that present the same signal level at each
location along the chain. A chain might snake through all the units on
one floor or all units vertically aligned with each other.

Splitters are purchased by the number of "ways" they divide the signal.
(for technical reasons, the outputs are not always identical) Taps are
purchased by the fraction of the signal they "tap" for their local
jack.

Early taps will strip a smaller fraction of the signal. After passing
through a few taps, the signal is enough weaker that a higher fraction
tap will be used. This strategic changing of the tap value continues
until the last location in the chain goes straight to the wall jack. If
the system is designed and installed properly, all locations will see a
similar (not necessarily identical) signal level.

There are additional complicating details such as the fact that higher
frequencies are attenuated (weakened) faster (shorter distances) than
lower frequencies. And, modern cable systems are bidirectional
(internet traffic must be able to get back to the cable company).

I seem to remember that Blonder Tongue does make taps (I don't have my
cable system design catalog at hand), but they don't include them in
catalogs provided for home users. Anyway, in my opinion, taps are more
trouble than they are worth in typical home applications. I've seen too
many professional installers who didn't understand how to properly use
taps -- and I assume they've had some training. I can't imagine that an
untrained home user (who won't read any books) could deal with them.

2-way or 4-way splits don't usually need amplifiers. In high signal
urban areas I will rarely use an amplifier even for an 8-way split. In
high signal urban areas affordable amplifiers will be overloaded and
you are better of without them. In low signal remote rural areas you'll
have to scrap for every little bit of signal you can capture -- be sure
to mount the amplifier on your mast.

-----------------------------------------------------------
spam: uce@ftc.gov
wordgame:123(abc):<14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13> (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------
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Anonymous
May 10, 2005 3:18:53 AM

Archived from groups: rec.audio.tech (More info?)

In article <isw-52AC88.20000909052005@comcast.dca.giganews.com>,
Isaac Wingfield <isw@witzend.com> wrote:

> In article <1115665741.028372.104250@z14g2000cwz.googlegroups.com>,
> fohara@san.rr.com wrote:
>
> > Does anyone have a part number and manufacturer name of a TV FM
> > splitter also known as a tap? I live very close to transmitters and
> > would like to keep the signals as clean as possible for both my tv and
> > radio receivers. I have new rooftop antennas and have already replaced
> > most cable and connectors.
> > I did some searches and called some distributors but only found general
> > references. Neither Radio Shack nor Blonder Tongue have this.
> > Thanks.
>
> You didn't mention whether you were using twin lead or coax. Assuming
> coax, any 75 ohm TV splitter will work just fine; the FM band is just
> above channel 6.
>
> Isaac

The typical UHF/VHF/FM splitter actually uses resistors for impedance
matching. Pop one open and see for yourself.

Real FM separators usually have a weak spot where channel 6 and the
lower end of FM meet. They're nearly impossible to find too. I just
avoid amping the FM and take a small hit on VHF reception quality.

My indoor setup looks like this:

UHF Ant ------------|
VHF/UHF mixer -- FM trap -- Amp -- TV
VHF Ant --splitter--|
|
|
FM

Maybe this is more practical for outdoor antennas:

<- outdoor | indoor ->
UHF Ant -- Amp --|
VHF/UHF mixer -- power -- splitter --- TV
VHF Ant ---------| injector |
FM
Anonymous
May 10, 2005 12:04:45 PM

Archived from groups: rec.audio.tech (More info?)

What you want is an attenuator. You can get a 75 ohm attenuator. They look
like a small barrel. Blonder Tongue should have them. They are good for the
complete FM and TV spectrum that is for cable feeds and LNB feeds.

If the interference is coming direct to the receiver's front end and not
from the cable, then the attenuator will not do any good.

--

JANA
_____


<fohara@san.rr.com> wrote in message
news:1115665741.028372.104250@z14g2000cwz.googlegroups.com...
Does anyone have a part number and manufacturer name of a TV FM
splitter also known as a tap? I live very close to transmitters and
would like to keep the signals as clean as possible for both my tv and
radio receivers. I have new rooftop antennas and have already replaced
most cable and connectors.
I did some searches and called some distributors but only found general
references. Neither Radio Shack nor Blonder Tongue have this.
Thanks.
Anonymous
May 10, 2005 1:06:02 PM

Archived from groups: rec.audio.tech (More info?)

Just to add, you will need to know the amount of DB you want to attenuate.

--

JANA
_____


"JANA" <jana@ca.inter.net> wrote in message
news:3ebmedF27gh7U6@uni-berlin.de...
What you want is an attenuator. You can get a 75 ohm attenuator. They look
like a small barrel. Blonder Tongue should have them. They are good for the
complete FM and TV spectrum that is for cable feeds and LNB feeds.

If the interference is coming direct to the receiver's front end and not
from the cable, then the attenuator will not do any good.

--

JANA
_____


<fohara@san.rr.com> wrote in message
news:1115665741.028372.104250@z14g2000cwz.googlegroups.com...
Does anyone have a part number and manufacturer name of a TV FM
splitter also known as a tap? I live very close to transmitters and
would like to keep the signals as clean as possible for both my tv and
radio receivers. I have new rooftop antennas and have already replaced
most cable and connectors.
I did some searches and called some distributors but only found general
references. Neither Radio Shack nor Blonder Tongue have this.
Thanks.
Anonymous
May 10, 2005 2:24:08 PM

Archived from groups: rec.audio.tech (More info?)

In <1115665741.028372.104250@z14g2000cwz.googlegroups.com>, on 05/09/05

at 12:09 PM, fohara@san.rr.com said:

>Does anyone have a part number and manufacturer name of a TV FM
>splitter also known as a tap? I live very close to transmitters and
>would like to keep the signals as clean as possible for both my tv and
>radio receivers. I have new rooftop antennas and have already replaced
>most cable and connectors.
>I did some searches and called some distributors but only found
>general references. Neither Radio Shack nor Blonder Tongue have this.
>Thanks.

I'm not sure what you are attempting to accomplish or if you are having
a problem or not. My previous reply, although technically correct may
not have been addressing your question. "Tap" has a fairly specific
meaning.

Look at the Radio Shack #15-1139 and #15-1252. They may accomplish what
you want to do, but my experience with Radio Shack antenna accessories
has been poor. This sort of device is fairly common. Many hardware
stores will stock them.

Unless you have an overloading issue with a lower quality FM tuner or
TV or an unusually high signal level, regular TV splitters will give
better results than those cheap, plastic TV/FM units. I prefer to use
splitters known as "hybrid" or "splitter/combiner". These are a bit
more expensive and harder to find, but they are higher quality units.
I've been especially pleased with the Channel Master and Channel+
units, but others have also worked well. Anything in a plastic case
(like the Radio Shack units above) is not a good idea.

-----------------------------------------------------------
spam: uce@ftc.gov
wordgame:123(abc):<14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13> (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------
Anonymous
May 10, 2005 7:32:46 PM

Archived from groups: rec.audio.tech (More info?)

To answer my own question...
Winegard CA-8800 available from Stark Electronic.com $15
MCM 33-350 available from Newark.com $4 but they may have an order min.
Magnavox M61013 for $4.
Pico Macom discontinued p/n FMTV-D available from Multicominc.com for
$1.16.

I know Radio Shack components are generally low quality.

My tv is a 15 year old LXI/Sears. My radio is a Pioneer VSX-1014TX (a
great buy at $400). I just shutoff cable service so I'm trying to build
an antenna that will last a long time and be hdtv ready. I have
separate VHF (16ft yagi, mfgr unknown) and UHF (Channel Master 4248)
antennas. These are on a 15 ft mast with a rotor. I bought Belden
1694A low loss coax at $.35/ft from Markertek. The longest cable run is
about 100 ft. I am also using T&B Snap-n-Seal connectors. This feeds 4
tvs and a FM receiver. I was using Blonder Tongue splitters but will
try a cable drop amp can handle higher signal inputs than a preamp
(like PDI or Electroline available on ebay). These are low noise
(2.4-3db). The 8 port amp adds 3db gain which may help me to get less
noise on some stations I like which are about 100 miles away. This
should compensate for splitter loss and line loss of signal strength.
The antenna installer said I could add the FM tap (band separator)
because it may minimize intereference both ways (tv/fm). It sounds like
a cheap bet. I know the unused ports must be terminated. The cable drop
amp does provide for future proofing if we go back to cable. It has
active return too. I will put the band separator before the amp. I
ordered the Winegard CA-8800. The PDI drop amp has been rec' but not
installed yet.

Someone explained that some ghosting is caused by the nearby stations
signal coming from multiple paths, also possibly leaking into poorly
shielded coax or loose connectors. The signal hits the tv at 2
different times and distorts the image. Hopefully the rotor will help
to mitigate any signal overload of the tv and radio transmitters 2
miles away.

Thanks for they replies!
Anonymous
May 10, 2005 8:56:23 PM

Archived from groups: rec.audio.tech (More info?)

fohara@san.rr.com wrote:
> Does anyone have a part number and manufacturer name of a TV FM
> splitter also known as a tap? I live very close to transmitters and
> would like to keep the signals as clean as possible for both my tv and
> radio receivers. I have new rooftop antennas and have already replaced
> most cable and connectors.
> I did some searches and called some distributors but only found
> general references. Neither Radio Shack nor Blonder Tongue have this.
> Thanks.

Are you perhaps looking for an FM *trap*? That's a device which attenuates
a particular frequency. It's used where there is a strong signal in the
area which is overloading the front-end of a receiver, regardless of where
it's tuned. You tune the trap for the strong signal, which alleviates the
overload from the strong signal so that weaker ones on other frequencies can
be heard.

jak
Anonymous
May 11, 2005 1:27:42 AM

Archived from groups: rec.audio.tech (More info?)

In article <mcmurtri-D6C902.23185309052005@corp-radius.supernews.com>,
Kevin McMurtrie <mcmurtri@dslextreme.com> wrote:

> In article <isw-52AC88.20000909052005@comcast.dca.giganews.com>,
> Isaac Wingfield <isw@witzend.com> wrote:
>
> > In article <1115665741.028372.104250@z14g2000cwz.googlegroups.com>,
> > fohara@san.rr.com wrote:
> >
> > > Does anyone have a part number and manufacturer name of a TV FM
> > > splitter also known as a tap? I live very close to transmitters and
> > > would like to keep the signals as clean as possible for both my tv and
> > > radio receivers. I have new rooftop antennas and have already replaced
> > > most cable and connectors.
> > > I did some searches and called some distributors but only found general
> > > references. Neither Radio Shack nor Blonder Tongue have this.
> > > Thanks.
> >
> > You didn't mention whether you were using twin lead or coax. Assuming
> > coax, any 75 ohm TV splitter will work just fine; the FM band is just
> > above channel 6.
> >
> > Isaac
>
> The typical UHF/VHF/FM splitter actually uses resistors for impedance
> matching. Pop one open and see for yourself.

I was not talking about UHF-VHF splitters. I was talking about "one coax
to two TV sets" splitters. One of those will nicely "split" the signal
so it can be connected to both a TV and an FM receiver. Very few
contemporary TV sets these days have separate inputs for VHF and UHF; it
never occurred to me that the word "splitter" would be confusing in
context.

You're right about V-U splitters, and also note that many V-U antennas
have a big notch at FM; you need to get a special antenna if you want
*full* coverage.

Isaac
Anonymous
May 11, 2005 2:04:59 AM

Archived from groups: rec.audio.tech (More info?)

>> Does anyone have a part number and manufacturer name of a TV FM
>> splitter also known as a tap? I live very close to transmitters and
>> would like to keep the signals as clean as possible for both my tv and
>> radio receivers. I have new rooftop antennas and have already replaced
>> most cable and connectors.

>Are you perhaps looking for an FM *trap*? That's a device which attenuates
>a particular frequency. It's used where there is a strong signal in the
>area which is overloading the front-end of a receiver, regardless of where
>it's tuned. You tune the trap for the strong signal, which alleviates the
>overload from the strong signal so that weaker ones on other frequencies can
>be heard.

The best source I have found for TV, cable-TV, and FM filters is a
company called Tin Lee Electronics, located in Toronto. Their web
site is at http://www.tinlee.com/

As one example, their CF7-FM is an FM band-pass filter. It will pass
the FM-band frequencies with little loss, but will provide a great
deal of attenuation (close to 30 dB) of most VHF television-band
frequencies.

Conversely, their CR7-FMU-40 is an FM band-stop filter. It passes the
VHF television frequencies, but blocks FM.

One way to apply these would be to feed a VHF-TV/FM roof antenna's
signal down to a two-way RF splitter. One port on the splitter would
go to a CF7-FM, and the filter's output would go to an A/V receiver or
other FM tuner. The other splitter port would go to a CR7-FMU-40, and
then to a television set. This arrangement would keep strong FM
signals out of the TV tuner, and strong TV signals out of the FM tuner.

Tin Lee also has narrow-band pass and notch filters, for more
specialized situations.

They have one filter I've never seen elsewhere... it's tuned to reject
the 144-148 MHz amateur-radio 2-meter band. This proved to be an
invaluable tool for maintaining domestic harmony in my house, as my
2-meter transmitter signals were getting into the TV system and
overpowering the little Radio Shack distribution amplifier, and wiping
out every channel. With the Tin Lee filter in place on the antenna,
the problem has disappeared.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
Anonymous
May 11, 2005 2:40:52 AM

Archived from groups: rec.audio.tech (More info?)

In article <1115764366.333084.286000@o13g2000cwo.googlegroups.com>,
<fohara@san.rr.com> wrote:

>To answer my own question...
>Winegard CA-8800 available from Stark Electronic.com $15
>MCM 33-350 available from Newark.com $4 but they may have an order min.
>Magnavox M61013 for $4.
>Pico Macom discontinued p/n FMTV-D available from Multicominc.com for
>$1.16.
>
>I know Radio Shack components are generally low quality.

Their little TV distribution amplifier is very prone to strong-signal
overload.

>My tv is a 15 year old LXI/Sears. My radio is a Pioneer VSX-1014TX (a
>great buy at $400). I just shutoff cable service so I'm trying to build
>an antenna that will last a long time and be hdtv ready. I have
>separate VHF (16ft yagi, mfgr unknown) and UHF (Channel Master 4248)
>antennas. These are on a 15 ft mast with a rotor. I bought Belden
>1694A low loss coax at $.35/ft from Markertek. The longest cable run is
>about 100 ft. I am also using T&B Snap-n-Seal connectors. This feeds 4
>tvs and a FM receiver. I was using Blonder Tongue splitters but will
>try a cable drop amp can handle higher signal inputs than a preamp
>(like PDI or Electroline available on ebay). These are low noise
>(2.4-3db). The 8 port amp adds 3db gain which may help me to get less
>noise on some stations I like which are about 100 miles away. This
>should compensate for splitter loss and line loss of signal strength.

100 miles is a very difficult "reach" unless you've got a lot of
altitude for your antenna. At that distance, both the transmitter and
receiver antennas are going to have to be up quite high, or each one
is going to be below the horizon from the other's point of view. When
this happens your signal strength drops off very sharply... you'll get
a bit of diffraction, and occasionally some tropospheric ducting, but
getting a consistently reliable signal is likely to be a real problem.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
Anonymous
May 11, 2005 2:40:53 AM

Archived from groups: rec.audio.tech (More info?)

Dave Platt wrote:
> In article <1115764366.333084.286000@o13g2000cwo.googlegroups.com>,
> <fohara@san.rr.com> wrote:
>
>> To answer my own question...
>> Winegard CA-8800 available from Stark Electronic.com $15
>> MCM 33-350 available from Newark.com $4 but they may have an order
>> min. Magnavox M61013 for $4.
>> Pico Macom discontinued p/n FMTV-D available from Multicominc.com for
>> $1.16.
>>
>> I know Radio Shack components are generally low quality.
>
> Their little TV distribution amplifier is very prone to strong-signal
> overload.
>
>> My tv is a 15 year old LXI/Sears. My radio is a Pioneer VSX-1014TX (a
>> great buy at $400). I just shutoff cable service so I'm trying to
>> build an antenna that will last a long time and be hdtv ready. I have
>> separate VHF (16ft yagi, mfgr unknown) and UHF (Channel Master 4248)
>> antennas. These are on a 15 ft mast with a rotor. I bought Belden
>> 1694A low loss coax at $.35/ft from Markertek. The longest cable run
>> is about 100 ft. I am also using T&B Snap-n-Seal connectors. This
>> feeds 4 tvs and a FM receiver. I was using Blonder Tongue splitters
>> but will try a cable drop amp can handle higher signal inputs than a
>> preamp (like PDI or Electroline available on ebay). These are low
>> noise (2.4-3db). The 8 port amp adds 3db gain which may help me to
>> get less noise on some stations I like which are about 100 miles
>> away. This should compensate for splitter loss and line loss of
>> signal strength.
>
> 100 miles is a very difficult "reach" unless you've got a lot of
> altitude for your antenna. At that distance, both the transmitter and
> receiver antennas are going to have to be up quite high, or each one
> is going to be below the horizon from the other's point of view. When
> this happens your signal strength drops off very sharply... you'll get
> a bit of diffraction, and occasionally some tropospheric ducting, but
> getting a consistently reliable signal is likely to be a real problem.

Also, do not depend on the distro amp to boost fringe signals. That's what
your antenna-mounted preamp is for. By the time the sig gets to the distro,
amplification is only for making up for loss in the split and cable. At
that point, you're amplifying noise and signal....

You might want to look into the traps previously described. With the high
gain scenario you describe, you won't necessarily be able to depend on
aiming the antenna to prevent receiver overload. The strong stations might
blast in at all points of the compass, due to reflections.

Finally, what was the source of the (unknown) yagi? Some of these were cut
for specific channels, back in the days before cable (where there was a
station in a different compass direction or somewhat further away from the
rest...some stations which meet those criteria actually advertised them on
air). Also, FM yagis were available. It's possible that you have one of
these. It's a remote possibility; but after getting everything into the air
and wired would not be a good time to find out....

jak
Anonymous
May 11, 2005 5:41:36 PM

Archived from groups: rec.audio.tech (More info?)

The 16 ft yagi was installed by a guy who is now retired. It looks like
the Winegard HD6065P for FM.
http://www.winegard.com/offair/pdf/hd6065p.pdf
It was up for a week as my only antenna recently. I got fair reception
on all channels 3-69. The Wade/Delhi/Jerrold VIP-307 is supposed to be
the best VHF antenna but that would cost $176 plus $60 shipping. I know
100 miles is a longshot. Atechfabrication.com make brackets to add some
vertical tilt which helps get distant stations. I bought one of their
brackets but my installer refused to use it. He said there is not point
in using it or a taller mast (mine is 15 ft above roof peak). In my
neighborhood, many antennas are taller than mine even though there are
no obstructions nearby.

Overall the image quality has improved greatly. I'll note the reception
quality of all stations with the rotor and do the same after adding the
8 port amp to judge the benefits and possible overloads. If some
distant stations are good but weak I'll see if I can convince him to
comeback. He only charges $60/hr while the only other installer I know
charges $90. I have spent about $300 so far to save $50 per month.
!