Signal weak without antenna amp, overloaded? with it, what t

[micky]

Use of an antenna amp.
Signal weak without it, overloaded? with it, what to do?

I have a moderately large outdoor TV antenna in my attic.

On its own, it gets all of the Baltimore TV stations, but not DC.

So I bought an antenna amp. AntennaCraft 10G212 30 dB High Gain TV/FM
Mast-Mounted TV Antenna Signal Amplifier
http://www.solidsignal.com/pview.asp?p=10G212&ss=503437 though FTR I was
dissatisfied with their customer service.

It has a gain control, which I set all the way at the top, so I wouldn't
have to go into the attic again. but later I actually read the
instructions and saw that I could (should) put 1/2 of the amp close to
my TV**, so now it's on the floor in the bedroom.

Now I can get all the Baltimore and Washington DC TV channels, (except
sometimes I can't get one or two of them) but sometimes channel 11 and
11.2 (Baltimore channels) don't come in, the screen is blank, or it goes
from good picture to blank for a variable length of time, and then back
to a good picture, then blank, and so forth. . I presume the tuner is
overloaded, now that there is an amp, since those channels worked fine
without the amp. I turned the gain down half-way and now down all the
way and it still happens. There are several programs on 11.2 that I
record, and I don't know until later that I have not recorded anything.

Am I amplifying the signal too much? Somewhere I have a signal
attenuator with co-axial connectors and an adjustment knob that I could
put between the amp and the DVDR. Should I try that first?

Or should I just buy a better amp? One that can be adjusted lower?
Any suggestions of what to buy?

Thanks.




**FWIW, not actually using a TV for the tuner. Using a Philips digital
DVDR with hard drive, with a digital tuner. Successfully running
several analog TVs off of that.

 

[Sjouke Burry]

On 31.03.15 6:18, micky wrote:

Use of an antenna amp.
Signal weak without it, overloaded? with it, what to do?

I have a moderately large outdoor TV antenna in my attic.

On its own, it gets all of the Baltimore TV stations, but not DC.

So I bought an antenna amp. AntennaCraft 10G212 30 dB High Gain TV/FM
Mast-Mounted TV Antenna Signal Amplifier
http://www.solidsignal.com/pview.asp?p=10G212&ss=503437 though FTR I was
dissatisfied with their customer service.

It has a gain control, which I set all the way at the top, so I wouldn't
have to go into the attic again. but later I actually read the
instructions and saw that I could (should) put 1/2 of the amp close to
my TV**, so now it's on the floor in the bedroom.

Now I can get all the Baltimore and Washington DC TV channels, (except
sometimes I can't get one or two of them) but sometimes channel 11 and
11.2 (Baltimore channels) don't come in, the screen is blank, or it goes
from good picture to blank for a variable length of time, and then back
to a good picture, then blank, and so forth. . I presume the tuner is
overloaded, now that there is an amp, since those channels worked fine
without the amp. I turned the gain down half-way and now down all the
way and it still happens. There are several programs on 11.2 that I
record, and I don't know until later that I have not recorded anything.

Am I amplifying the signal too much? Somewhere I have a signal
attenuator with co-axial connectors and an adjustment knob that I could
put between the amp and the DVDR. Should I try that first?

Or should I just buy a better amp? One that can be adjusted lower?
Any suggestions of what to buy?

Thanks.




**FWIW, not actually using a TV for the tuner. Using a Philips digital
DVDR with hard drive, with a digital tuner. Successfully running
several analog TVs off of that.

You are in effect mixing strong signals with weak signals,
causing cross-modulation and reception failure.
Antenne amps are very "good" at that.........
Get a separate areal for DC, one with high gain selectivity,
to pull in those channels, and try aiming in such a way as to
minimize the strong local, nearby ones.

 

[Ron D.]

FM can overload the amp, Some amplifiers have a switchable FM trap or you can add one.

 

[Dave Platt]

In article <s96khal8v5c0qtb0t0fe74bc5iivkim646@4ax.com>,
micky <NONONOmisc07@bigfoot.com> wrote:

Use of an antenna amp.
Signal weak without it, overloaded? with it, what to do?

I have a moderately large outdoor TV antenna in my attic.

Is your antenna on a rotator? Can you adjust its pointing direction
on a per-station basis?

Now I can get all the Baltimore and Washington DC TV channels, (except
sometimes I can't get one or two of them) but sometimes channel 11 and
11.2 (Baltimore channels) don't come in, the screen is blank, or it goes
from good picture to blank for a variable length of time, and then back
to a good picture, then blank, and so forth. . I presume the tuner is
overloaded, now that there is an amp, since those channels worked fine
without the amp. I turned the gain down half-way and now down all the
way and it still happens. There are several programs on 11.2 that I
record, and I don't know until later that I have not recorded anything.

Am I amplifying the signal too much? Somewhere I have a signal
attenuator with co-axial connectors and an adjustment knob that I could
put between the amp and the DVDR. Should I try that first?

Reading between the lines, it looks to me as if this is actually two
amplifiers - a fixed-gain 15 dB amplifier which goes up at the
antenna, and a variable-gain amplifier in the "indoor" portion.

Unfortunately, I suspect that you may be dealing with a signal
overload problem *before* the signal reaches your TV tuner. It's
quite common for these consumer-grade TV amplifiers to have very poor
strong-signal-overload resiliance. If you've got several strong local
stations in your area, the first-stage amp (near the antenna) could
very well be overloading and distorting. The distortion will cause
intermodulation between these strong signals, and the intermodulation
products are very likely to "bleed into" numerous stations and degrade
the signal quality. Once this happens, your signal quality is
ruined... turning down the gain of the second-stage "indoor" amplifier
won't help... you can't make pig out of sausage :-(

Also, these cheap amps often have a high "noise figure" - the amp
transistor or MMIC introduces enough noise of its own to degrade the
signal significantly. The AntennaCraft is rated at under 4 dB VHF and
under 3.5 dB UHF, which means that its output noise is roughly twice
that of an unamplified antenna. Not terrible, but not
state-of-the-art.

The "gotcha" about amps is that it's very likely that the tuner in
your DVR has a *lower* noise figure in its front end, than any
amplifier you can add at an affordable price. If you amplify the
incoming signal, and then run it right to a single device (e.g. DVR),
you actually aren't doing the DVR any favors. This is especially true
for any amplification you do right down next to the DVR.

Or should I just buy a better amp? One that can be adjusted lower?
Any suggestions of what to buy?

If it's possible, I would recommend that you address the problems
"earlier in the chain". Get your antenna up out of the attic, mount
it on a mast (as high as you can safely arrange, with proper
guy-wiring) and try different aiming directions until you find the one
which works best in practice. Hint: this might *not* be aiming
directly towards the most-difficult stations.

Antenna height makes a huge difference with TV reception of "fringe"
stations. The antenna can "see further" over the horizon, and by
getting it up out of the "ground clutter" you will eliminate or reduce
a lot of signal reflections ("multipath").

Unfortunately, since you're using a DVR which changes channels
automatically, you may not be able to use one of the best "un-secret
weapons" for TV reception - an antenna rotator. The higher the gain
of the antenna, the more sensitive it will be to aiming.

If you do decide to use an amplifier, you're going to want one which
is extremely resistant to overload, *and* has a very low "noise
figure". A "professional-grade" CATV amplifier module might do the
trick... or, it might end up boosting the strong local signals so much
that they overload your DVR's tuner and you'd be right back where you
are today.

So, I think your best bet is the classic one: as good an antenna as
you can afford, mounted up as high as you can manage, wired down to
your DVR with the lowest-loss 75-ohm coax you can locate
(quad-shielded satellite-grade RG-6, rather than cheap RG-59), and
aimed as well as possible. Since you're feeding the signal only to
one device (the DVR) you won't need a splitter, hence you won't need
amplification to overcome losses in the splitter.

 

[mike]

On 3/31/2015 11:37 AM, Dave Platt wrote:

In article <s96khal8v5c0qtb0t0fe74bc5iivkim646@4ax.com>,
micky <NONONOmisc07@bigfoot.com> wrote:
Use of an antenna amp.
Signal weak without it, overloaded? with it, what to do?

I have a moderately large outdoor TV antenna in my attic.

Is your antenna on a rotator? Can you adjust its pointing direction
on a per-station basis?

This doesn't work well if you're recording several stations at once.

I went thru this hassle back when they converted the USA to ATSC.
None of my stations are fringe. Mostly in the same direction.

I found that the ability to receive a given channel was far more
sensitive to signal quality than signal strength.

One simple measure of quality is the flatness of the "bart's head"
display on a spectrum analyzer. This appeared to be a function
of multipath. But there does seem to be a relationship between
signal strength and the ability of a tuner to resolve a low quality
signal.
I ended up with an amplified splitter and four separate attenuators
to four tuner cards. Careful alignment of the antenna, careful
adjustment of the attenuators and restricting the poorest quality channels
to the best tuners gave me a system that mostly worked most of the time.

The situation improved over the years as tuners got better. I also moved
the antenna further from the big metal building in my neighbor's yard.
I no longer
need the separate adjustable attenuators...but the whole system is
right on the edge of not working.

Now I can get all the Baltimore and Washington DC TV channels, (except
sometimes I can't get one or two of them) but sometimes channel 11 and
11.2 (Baltimore channels) don't come in, the screen is blank, or it goes
from good picture to blank for a variable length of time, and then back
to a good picture, then blank, and so forth. . I presume the tuner is
overloaded, now that there is an amp, since those channels worked fine
without the amp. I turned the gain down half-way and now down all the
way and it still happens. There are several programs on 11.2 that I
record, and I don't know until later that I have not recorded anything.

Am I amplifying the signal too much? Somewhere I have a signal
attenuator with co-axial connectors and an adjustment knob that I could
put between the amp and the DVDR. Should I try that first?

Reading between the lines, it looks to me as if this is actually two
amplifiers - a fixed-gain 15 dB amplifier which goes up at the
antenna, and a variable-gain amplifier in the "indoor" portion.

Unfortunately, I suspect that you may be dealing with a signal
overload problem *before* the signal reaches your TV tuner. It's
quite common for these consumer-grade TV amplifiers to have very poor
strong-signal-overload resiliance. If you've got several strong local
stations in your area, the first-stage amp (near the antenna) could
very well be overloading and distorting. The distortion will cause
intermodulation between these strong signals, and the intermodulation
products are very likely to "bleed into" numerous stations and degrade
the signal quality. Once this happens, your signal quality is
ruined... turning down the gain of the second-stage "indoor" amplifier
won't help... you can't make pig out of sausage :-(

Also, these cheap amps often have a high "noise figure" - the amp
transistor or MMIC introduces enough noise of its own to degrade the
signal significantly. The AntennaCraft is rated at under 4 dB VHF and
under 3.5 dB UHF, which means that its output noise is roughly twice
that of an unamplified antenna. Not terrible, but not
state-of-the-art.

The "gotcha" about amps is that it's very likely that the tuner in
your DVR has a *lower* noise figure in its front end, than any
amplifier you can add at an affordable price. If you amplify the
incoming signal, and then run it right to a single device (e.g. DVR),
you actually aren't doing the DVR any favors. This is especially true
for any amplification you do right down next to the DVR.

Or should I just buy a better amp? One that can be adjusted lower?
Any suggestions of what to buy?

If it's possible, I would recommend that you address the problems
"earlier in the chain". Get your antenna up out of the attic, mount
it on a mast (as high as you can safely arrange, with proper
guy-wiring) and try different aiming directions until you find the one
which works best in practice. Hint: this might *not* be aiming
directly towards the most-difficult stations.

Antenna height makes a huge difference with TV reception of "fringe"
stations. The antenna can "see further" over the horizon, and by
getting it up out of the "ground clutter" you will eliminate or reduce
a lot of signal reflections ("multipath").

Unfortunately, since you're using a DVR which changes channels
automatically, you may not be able to use one of the best "un-secret
weapons" for TV reception - an antenna rotator. The higher the gain
of the antenna, the more sensitive it will be to aiming.

If you do decide to use an amplifier, you're going to want one which
is extremely resistant to overload, *and* has a very low "noise
figure". A "professional-grade" CATV amplifier module might do the
trick... or, it might end up boosting the strong local signals so much
that they overload your DVR's tuner and you'd be right back where you
are today.

So, I think your best bet is the classic one: as good an antenna as
you can afford, mounted up as high as you can manage, wired down to
your DVR with the lowest-loss 75-ohm coax you can locate
(quad-shielded satellite-grade RG-6, rather than cheap RG-59), and
aimed as well as possible. Since you're feeding the signal only to
one device (the DVR) you won't need a splitter, hence you won't need
amplification to overcome losses in the splitter.

 

[micky]

On Tue, 31 Mar 2015 08:05:00 +0200, Sjouke Burry
<burrynulnulfour@ppllaanneett.nnll> wrote:

On 31.03.15 6:18, micky wrote:
Use of an antenna amp.
Signal weak without it, overloaded? with it, what to do?

I have a moderately large outdoor TV antenna in my attic.

On its own, it gets all of the Baltimore TV stations, but not DC.

So I bought an antenna amp. AntennaCraft 10G212 30 dB High Gain TV/FM
Mast-Mounted TV Antenna Signal Amplifier
http://www.solidsignal.com/pview.asp?p=10G212&ss=503437 though FTR I was
dissatisfied with their customer service.

It has a gain control, which I set all the way at the top, so I wouldn't
have to go into the attic again. but later I actually read the
instructions and saw that I could (should) put 1/2 of the amp close to
my TV**, so now it's on the floor in the bedroom.

Now I can get all the Baltimore and Washington DC TV channels, (except
sometimes I can't get one or two of them) but sometimes channel 11 and
11.2 (Baltimore channels) don't come in, the screen is blank, or it goes
from good picture to blank for a variable length of time, and then back
to a good picture, then blank, and so forth. . I presume the tuner is
overloaded, now that there is an amp, since those channels worked fine
without the amp. I turned the gain down half-way and now down all the
way and it still happens. There are several programs on 11.2 that I
record, and I don't know until later that I have not recorded anything.

Am I amplifying the signal too much? Somewhere I have a signal
attenuator with co-axial connectors and an adjustment knob that I could
put between the amp and the DVDR. Should I try that first?

Or should I just buy a better amp? One that can be adjusted lower?
Any suggestions of what to buy?

Thanks.




**FWIW, not actually using a TV for the tuner. Using a Philips digital
DVDR with hard drive, with a digital tuner. Successfully running
several analog TVs off of that.

You are in effect mixing strong signals with weak signals,
causing cross-modulation and reception failure.
Antenne amps are very "good" at that.........
Get a separate areal for DC, one with high gain selectivity,
to pull in those channels, and try aiming in such a way as to
minimize the strong local, nearby ones.

That was my intention with this antenna. And I used antennaweb.com or
the other similar site to see what direction the DC stations were, and
they were pretty much in the same direction, and by luck, my house
points that way.

This is the antenna I have.
Winegard HD 7696P High Definition VHF/UHF HD7696 Series TV Antenna
(HD7696P)
http://www.solidsignal.com/pview.asp?p=hd7696p

With over 80% of Local TV markets being on High Band VHF and UHF, the
HD-769 Series has been specifically tuned for channels 7 - 69.
Estimated Range: 50 miles VHF & 40 miles UHF
Great mid range Directional antenna with an aproximate beam width of 30
degrees

Estimated Range: 50 miles VHF & 40 miles UHF
Great mid range Directional antenna with an aproximate beam width of 30
degrees

*Note: This antenna can receive stations 2-6 in most areas due to
the fact they are generally broadcast on higher unused UHF or VHF
frequency numbers in the area. Our techs can verify this with your zip
code information

************
Yeah, but maybe 11 is broadcast on a lower UHF Frequency. I have to
check on that.
************

Active Elements: 41
UHF Elements: 26
VHF Elements: 15
Boom Length: 110.75"
Maximum Width: 36"
Element Diameter: 3/8"
Turning Radius 70.6"
Shipping Weight 10.8 lbs.


The local stations, at least channel 11 that I can't always get, is
about 90^ in a different direction from the orientation of the antenna.
I thought that would also make the signal weak, but this one station,
probably the strongest in Baltmore (I got that idea somewhere) still
seems to be overloaded.


I was going to buy a small, antenna for th e###

 

[micky]

On Tue, 31 Mar 2015 15:14:48 -0700 (PDT), "Ron D."
<Ron.Dozier@gmail.com> wrote:

>FM can overload the amp, Some amplifiers have a switchable FM trap or you can add one.

Yes, it has one of those, and I switched it on and off while watching
the picture, and I saw no change. However I didn't do this while
watching the picture on either of the two stations that don't work well!

I'll do that soon. Thanks.

 

[micky]

On Tue, 31 Mar 2015 11:37:20 -0700, dplatt@coop.radagast.org (Dave
Platt) wrote:

In article <s96khal8v5c0qtb0t0fe74bc5iivkim646@4ax.com>,
micky <NONONOmisc07@bigfoot.com> wrote:
Use of an antenna amp.
Signal weak without it, overloaded? with it, what to do?

I have a moderately large outdoor TV antenna in my attic.

Is your antenna on a rotator? Can you adjust its pointing direction
on a per-station basis?

No rotator.

Now I can get all the Baltimore and Washington DC TV channels, (except
sometimes I can't get one or two of them) but sometimes channel 11 and
11.2 (Baltimore channels) don't come in, the screen is blank, or it goes
from good picture to blank for a variable length of time, and then back
to a good picture, then blank, and so forth. . I presume the tuner is
overloaded, now that there is an amp, since those channels worked fine
without the amp. I turned the gain down half-way and now down all the
way and it still happens. There are several programs on 11.2 that I
record, and I don't know until later that I have not recorded anything.

Am I amplifying the signal too much? Somewhere I have a signal
attenuator with co-axial connectors and an adjustment knob that I could
put between the amp and the DVDR. Should I try that first?

Reading between the lines, it looks to me as if this is actually two
amplifiers - a fixed-gain 15 dB amplifier which goes up at the
antenna, and a variable-gain amplifier in the "indoor" portion.

Do they really do this? Especially for only 30 dollars**. I had
assumed there was just one amp, at the antenna, and the indoor part was
the power supply (since it plugs into the wall) and a rheostat.

**I was willing to spend more, but there were so many I coudln't make up
my mind.

Unfortunately, I suspect that you may be dealing with a signal
overload problem *before* the signal reaches your TV tuner. It's
quite common for these consumer-grade TV amplifiers to have very poor
strong-signal-overload resiliance. If you've got several strong local
stations in your area, the first-stage amp (near the antenna) could
very well be overloading and distorting. The distortion will cause
intermodulation between these strong signals, and the intermodulation
products are very likely to "bleed into" numerous stations and degrade
the signal quality. Once this happens, your signal quality is
ruined... turning down the gain of the second-stage "indoor" amplifier
won't help... you can't make pig out of sausage :-(

Also, these cheap amps often have a high "noise figure" - the amp
transistor or MMIC introduces enough noise of its own to degrade the
signal significantly. The AntennaCraft is rated at under 4 dB VHF and
under 3.5 dB UHF, which means that its output noise is roughly twice
that of an unamplified antenna. Not terrible, but not
state-of-the-art.

The "gotcha" about amps is that it's very likely that the tuner in
your DVR has a *lower* noise figure in its front end, than any
amplifier you can add at an affordable price. If you amplify the
incoming signal, and then run it right to a single device (e.g. DVR),
you actually aren't doing the DVR any favors. This is especially true
for any amplification you do right down next to the DVR.

Or should I just buy a better amp? One that can be adjusted lower?
Any suggestions of what to buy?

If it's possible, I would recommend that you address the problems
"earlier in the chain". Get your antenna up out of the attic, mount
it on a mast (as high as you can safely arrange, with proper

I have no place to keep a ladder and have to borrow one every time I
need one. Plus I'm 68** and fat, and while I might have put an antenna
on the roof 10 or 20 years ago, I know I'm not going to do it now.

** I don't feel old and I've managed to lose some of the weight, but
still. And oh yeah, I have osteoporosis, because of
hyperparathyroidism. Surgery is scheduled for 9 days from now, and the
osteo may reverse itself without more drugs after they cut out the
little benign-but-stiill-fouling--me-up tumor. No bigger than a plain
M&M or a bean in Heinz baked beans. But the osteo hasn't reversed yet
and might not do so completely. I think only one in a 1000 people get
this. All this means I can't risk breaking a bone. (Though I've
fallen twice in the last 6 months without breaking anything.)

guy-wiring) and try different aiming directions until you find the one
which works best in practice. Hint: this might *not* be aiming
directly towards the most-difficult stations.

I did start with the direction of the station and tnen tried re-aiming
it, by bringing a TV into the attic, and using my RF relay and the
remote to change stations on the DVDR in my bedroom. It seemed to make
no difference, but I didn't spend time on the Baltimore stations. It's
not too late to do that, in the attic.

Antenna height makes a huge difference with TV reception of "fringe"
stations. The antenna can "see further" over the horizon, and by
getting it up out of the "ground clutter" you will eliminate or reduce
a lot of signal reflections ("multipath").

But this one bad station is only 10 miles away, on "Television Hill",
which has all but one or two Baltimore TV stations. It's actually a
hill. ;-) Two or 3 miles north of downtown, and I live west and
somewhat north of downtown. .

Unfortunately, since you're using a DVR which changes channels
automatically, you may not be able to use one of the best "un-secret
weapons" for TV reception - an antenna rotator. The higher the gain
of the antenna, the more sensitive it will be to aiming.

Absolutely. The longer I have it, the more even when I'm home I don't
pay attention to when it starts recording. By watching the recorded
version, I can fast forward through the commercials and through the
annoying guy on the People's Court.

If you do decide to use an amplifier, you're going to want one which
is extremely resistant to overload, *and* has a very low "noise
figure". A "professional-grade" CATV amplifier module might do the
trick... or, it might end up boosting the strong local signals so much
that they overload your DVR's tuner and you'd be right back where you
are today.

I'd hate to spend professional-grade momey and have results no better.

So, I think your best bet is the classic one: as good an antenna as
you can afford, mounted up as high as you can manage, wired down to
your DVR with the lowest-loss 75-ohm coax you can locate
(quad-shielded satellite-grade RG-6, rather than cheap RG-59), and

I'll check what cabel I'm using.

aimed as well as possible. Since you're feeding the signal only to
one device (the DVR) you won't need a splitter, hence you won't need
amplification to overcome losses in the splitter.

Thanks a lot.
>