Stacking Winegard HD-6065P antennas
 

Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote:

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote:

Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote:
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to email a
number of suppliers until I found the second one. I bet there are some
still in storage somewhere, email different places that sell Winegard,
you may still find one.
John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.
Greg

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your units of
measure, you wouldn't be having such problems.

You've got it backwards, Jeff. Twice the voltage is 4 times the power.
1.414 times the voltage would be twice the power.

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:
If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.


I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas with two
transmitters. Two antennas, one transmitter, with one splitter would only
give 3 dB power increase at the receiver. I'm just thinking out loud. I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg

Stacking Winegard HD-6065P antennas
 

gregz wrote:
Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote:

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote:

Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote:
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to email a
number of suppliers until I found the second one. I bet there are some
still in storage somewhere, email different places that sell Winegard,
you may still find one.
John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.
Greg

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your units of
measure, you wouldn't be having such problems.

You've got it backwards, Jeff. Twice the voltage is 4 times the power.
1.414 times the voltage would be twice the power.

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:
If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.


I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas with two
transmitters. Two antennas, one transmitter, with one splitter would only
give 3 dB power increase at the receiver. I'm just thinking out loud. I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg

Tomorrow I will think the reverse of the antenna reception combining. It
does not work for me right now.

Greg

Stacking Winegard HD-6065P antennas
 

On 1/7/2014 2:29 AM, gregz wrote:
Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote:

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote:

Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote:
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to email a
number of suppliers until I found the second one. I bet there are some
still in storage somewhere, email different places that sell Winegard,
you may still find one.
John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.
Greg

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your units of
measure, you wouldn't be having such problems.

You've got it backwards, Jeff. Twice the voltage is 4 times the power.
1.414 times the voltage would be twice the power.

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:
If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.


I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas with two
transmitters. Two antennas, one transmitter, with one splitter would only
give 3 dB power increase at the receiver. I'm just thinking out loud. I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg


No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but who
cares about the laws of physics? :)

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

Stacking Winegard HD-6065P antennas
 

In message , Jerry Stuckle
writes
On 1/7/2014 2:29 AM, gregz wrote:
Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote:

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote:

Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote:
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work
swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to email a
number of suppliers until I found the second one. I bet there are some
still in storage somewhere, email different places that sell Winegard,
you may still find one.
John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.
Greg

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your units of
measure, you wouldn't be having such problems.

You've got it backwards, Jeff. Twice the voltage is 4 times the power.
1.414 times the voltage would be twice the power.

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:
If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.


I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas with two
transmitters. Two antennas, one transmitter, with one splitter would only
give 3 dB power increase at the receiver. I'm just thinking out loud. I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg


No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but
who cares about the laws of physics? :)

Two identical receiving antennas would provide twice the signal voltage
if their RF outputs were connected in series.

One way of doing this would be for coax feed from each antenna to be
connected to the primary of a 1:1 RF transformer, and the secondaries of
the two transformers were connected in series. So if each antenna
delivered 1V from a resistive source impedance (R) of 1 ohm into a
matched resistive load of 1 ohm, the two secondaries in series would
provide 2V. However, the output impedance of the two secondaries would
be twice that of each antenna, ie 2R. To preserve matching, the load
would also have to be 2R.

However, the snag is.....
The matched power from each antenna is 1V squared divided by 1 ohm
(=1W), but the matched power from the combined antennas is 2V squared
divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB).

Of course, if the receiver input was not matched, and its impedance was
much higher than R or 2R, it might be possible to benefit from adding
the two antenna signals in this way. Has anybody tried this?
--
Ian

Stacking Winegard HD-6065P antennas
 

No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but
who cares about the laws of physics? :)

Two identical receiving antennas would provide twice the signal voltage
if their RF outputs were connected in series.

One way of doing this would be for coax feed from each antenna to be
connected to the primary of a 1:1 RF transformer, and the secondaries of
the two transformers were connected in series. So if each antenna
delivered 1V from a resistive source impedance (R) of 1 ohm into a
matched resistive load of 1 ohm, the two secondaries in series would
provide 2V. However, the output impedance of the two secondaries would
be twice that of each antenna, ie 2R. To preserve matching, the load
would also have to be 2R.

However, the snag is.....
The matched power from each antenna is 1V squared divided by 1 ohm
(=1W), but the matched power from the combined antennas is 2V squared
divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB).

Of course, if the receiver input was not matched, and its impedance was
much higher than R or 2R, it might be possible to benefit from adding
the two antenna signals in this way. Has anybody tried this?

I don't think anyone would try this because every television input is
either 75 or 300 ohms or both. Hoping for an input of 1000 ohms would be
a vain hope.

Stacking Winegard HD-6065P antennas
 

In message , boomer
writes


No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but
who cares about the laws of physics? :)

Two identical receiving antennas would provide twice the signal voltage
if their RF outputs were connected in series.

One way of doing this would be for coax feed from each antenna to be
connected to the primary of a 1:1 RF transformer, and the secondaries of
the two transformers were connected in series. So if each antenna
delivered 1V from a resistive source impedance (R) of 1 ohm into a
matched resistive load of 1 ohm, the two secondaries in series would
provide 2V. However, the output impedance of the two secondaries would
be twice that of each antenna, ie 2R. To preserve matching, the load
would also have to be 2R.

However, the snag is.....
The matched power from each antenna is 1V squared divided by 1 ohm
(=1W), but the matched power from the combined antennas is 2V squared
divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB).

Of course, if the receiver input was not matched, and its impedance was
much higher than R or 2R, it might be possible to benefit from adding
the two antenna signals in this way. Has anybody tried this?

I don't think anyone would try this because every television input is
either 75 or 300 ohms or both.

I think you might be surprised at how unlike the supposed 75 or 300 ohms
some TV sets might be.

Hoping for an input of 1000 ohms would be a vain hope.

Possibly a purpose-built preamp could be designed to have a distinctly
higher input impedance. Of course, it would also have to have an
appropriately low noise figure (certainly at least as good as the
receiver).
--
Ian

Stacking Winegard HD-6065P antennas
 

On 1/7/2014 9:06 AM, Ian Jackson wrote:
In message , Jerry Stuckle
writes
On 1/7/2014 2:29 AM, gregz wrote:
Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote:

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote:

Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote:
wrote:
"only 3 db", but that's twice the signal. I have mine stacked
12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work
swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to
email a
number of suppliers until I found the second one. I bet there
are some
still in storage somewhere, email different places that sell
Winegard,
you may still find one.
John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the
signal.
Greg

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your
units of
measure, you wouldn't be having such problems.

You've got it backwards, Jeff. Twice the voltage is 4 times the
power.
1.414 times the voltage would be twice the power.

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:
If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.


I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas
with two
transmitters. Two antennas, one transmitter, with one splitter would
only
give 3 dB power increase at the receiver. I'm just thinking out loud.
I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg


No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but
who cares about the laws of physics? :)

Two identical receiving antennas would provide twice the signal voltage
if their RF outputs were connected in series.

One way of doing this would be for coax feed from each antenna to be
connected to the primary of a 1:1 RF transformer, and the secondaries of
the two transformers were connected in series. So if each antenna
delivered 1V from a resistive source impedance (R) of 1 ohm into a
matched resistive load of 1 ohm, the two secondaries in series would
provide 2V. However, the output impedance of the two secondaries would
be twice that of each antenna, ie 2R. To preserve matching, the load
would also have to be 2R.

However, the snag is.....
The matched power from each antenna is 1V squared divided by 1 ohm
(=1W), but the matched power from the combined antennas is 2V squared
divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB).

Of course, if the receiver input was not matched, and its impedance was
much higher than R or 2R, it might be possible to benefit from adding
the two antenna signals in this way. Has anybody tried this?

But then I DID qualify my statement with "if the resistance (impedance
in this case) stays the same". In your case, as you indicated, it is
not the same.

For the same impedance you would need a matching network. Assuming no
loss in the matching network, the output would be 1.414V.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.

==================

Stacking Winegard HD-6065P antennas
 

On Sun, 5 Jan 2014 00:01:47 -0500, "Ralph Mowery"
wrote:

I understand the idea of using 'perfect' items in electronics, then going
for more exect calculations if needed.

I like to design perfect antennas and circuits as a sanity check to
see if it can be done. Then, I throw in the losses and see what
happens. It's also a crude form of sensitivity analysis, which tells
me which parameters are most important.

The Wilkinson combiner is possiable for relative narrow frequencies. Not
sure if building one out of descrete components or full size transmission
lines would be broad enough for the whole FM band either. Wild guess it
would be about the same if just two pieces of transmission line of the
correct impedance and length were used.

Good guess. Discrete or coaxial performance (loss, isolation, and
bandwidth) are about the same. You're also correct that it wouldn't
cover the entire FM band. I could do it with a single stage Wilkinson
combiner by lowering the Q of the components. However, that will
increase the losses, which is not a great idea.

Much better is to use a multi-stage Wilkinson combiner:
http://www.microwaves101.com/encyclopedia/wilkinson_multistage.cfm
It's a common stripline technique. You probably recognize the general
pattern:
http://www.eee.bham.ac.uk/yatesac/Web%20PDF%27s/Test%20Gear/Wideband%20Wilkinson%20Coupler_1-2%20GHz_Layout.pdf
http://www.eee.bham.ac.uk/yatesac/Web%20Pages/Wideband%20Wilkinson%20Splitter%20&%20Combiner.htm

Isn't the Wilkinson combiner just two pieces of transmission line (or
simulated with components) with a resistor across two of the ports to
absorbe the diffeance if the loads/sources are not ballanced ?

The resistor is NOT to provide a load in case of an imbalance. It's
to provide an impedance match for a 180 degree out of phase path
between input/output ports. A signal that tries to go between the two
input/output ports has two paths along which it can go. One is down
one 1/4 wave coax, and up the other 1/4 wave coax, resulting in a 180
degree phase shift. The other is through the resistor with a 0 degree
phase shift. If everything is roughly impedance matched, the signals
through the two paths cancel, resulting in very good isolation between
ports.

As the subject is combining, I have not looked into the losses of splitting,
but it would be 6 db for the simple resistor designs not counting the minor
losses. That would be 3 db for the ports and 3 db lost in the resistors.

Yep, that's correct.
http://www.microwaves101.com/encyclopedia/resistive_splitters.cfm

To combind signals you would get the loss of the resistors of 3 db and a
fraction of other loss.

Yep, that's correct.

I am using a HP 8924C for a test set. It has just about everything you can
think of for a service monitor. Calibrated from 30 to 1000 MHz but usuable
uncalibrated to about a half of a mhz.
http://www.amtronix.com/hp8924c60.htm

http://axfp.org/god-bless-the-hp-8924c-a-tale-and-tutorial-of-the-service-monitor/
Nice. I'm into opening a museum of antique test equipment:
http://802.11junk.com/jeffl/pics/home/slides/test-equip-mess.html

Yes, phasing harnesses on antennas are not totally loseless, but will be
mainly whatever the loss of the coax is between the elements.

Nope. A phasing harness is much like the Wilkinson combiner without
the balancing resistor. Isolation between antennas would be nice, but
kinda futile with the antennas that close. Like the Wilkinson
combiner, the cables are odd multiples of 1/4 wave electrical. Like
the Wilkinson, such phasing harnesses have a limited bandwidth, where
losses increase the further away one gets from resonance. In other
words, you can't supply a single number for the losses in a phasing
harness. What's needed are numbers for the losses at resonance and at
band edges.

At this time, I still don't know if a Wilkinson combiner or phasing
harness will have sufficient bandwidth to cover the FM broadcast band.
That's 20 Mhz bandwidth at 100 Mhz or Q=5. I don't think that's
possible. To make my life more difficult, it's not possible to easily
model coax cables using NEC2. I've been using a mythical 50 ohm open
wire line, which can be modeled.

I would recommend either a messy multistage Wilkinson power
splitter/combiner, or go the broadband route with a common CATV/FM
power splitter/combiner.

If were the origional poster and there were not too many transmitters near
me, I would try a good preamp first. Mast mounted if possiable as it is for
receive only.

Preamps are a mixed blessing. With a good antenna, they can pickup
signals at impressive distances. However, they can also overload
miserably if there is a nearby transmitter on a nearby frequency. The
directionality of a Yagi is a big help, but if the nearby transmitter
is too close, the amplifier will overload, desensitize, belch
intermod, or otherwise cause problems. At best, the tower mounted amp
should be used only to compensate for coax losses. Any more gain than
that reduces the dynamic range of the system. Therefore, if the coax
cables is fairly short, and the cable is low loss, I wouldn't bother
with an amplifier. If the coax cable run is long and/or the coax is
junk, a tower mounted amp might be worth trying.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Stacking Winegard HD-6065P antennas
 

"Jeff Liebermann" wrote in message
...
On Mon, 6 Jan 2014 06:28:11 +0000 (UTC), gregz
wrote:

wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to email a
number of suppliers until I found the second one. I bet there are some
still in storage somewhere, email different places that sell Winegard,
you may still find one.

John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Nope. Power is by the square of the voltage:
P = V^2 / R
If you double the voltage, you get 4 times the power.
A 1.414 times increase in voltage will produce twice the power.

I tried to convert the antenna model of the HD-6066P antenna from the
AO .ant format to .nec using 4NEC2 and failed. The plan was to model
the stacked arrangement and see what happens:
http://www.ham-radio.com/k6sti/hd6065p.htm
The .ant file imported without error, the wire tables and images look
correct, but the pattern is more like a point source than a gain
antenna. I'll look at it later to see where I screwed up, but it
would be nice if someone would look at the problem.

I just set up an experiment. I connected my roof antenna to my signal
level meter and read the signal strength of my Channel 10. It was 10 dBmV,
the unit typically used for TV signal strength work.

Next, I connected the same roof antenna to the inport port of one of a pair
of passive splitters connected back-to-back with equal short lengths of the
same 75-ohm cable.

Finally, I connected the output port of this network to the signal level
meter and observed a signal that was approximately 1.25 dBmV less. (A
quarter of a dBmV is about as close as I can reliably read; individual whole
number marks are only a few mm apart.)

Thus, I conclude that the 1 dB nominal loss for a passive splitter -- either
combining or splitting -- is confirmed. Combining two identical suignals
does get you something more than one, alone.

RELATED: When I used identical twin UHF antennas side-by-side, separated by
a free-space half-wave distance to cancel interference from one side, it
worked nicely and showed about the same loss figures as above. That is, my
reading for two antennas combined was about 2 dBmV higher than for either of
the twin antennas alone, thus reflecting the 1dB loss in the combiner.

Combining antennas can be an uncertain business because the phase
relationships change with wavelength; the arrangement that strengthens one
channel may weaken another channel if the respective signals come from
different directions and/or the cable lengths are not matched. It's a
matter of reinforcement or cancellation, depending on phase relationships.

"Sal"
(KD6VKW)

Stacking Winegard HD-6065P antennas
 

Jerry Stuckle wrote:
On 1/7/2014 2:29 AM, gregz wrote:
Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote:

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote:

Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote:
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet,
but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
got mine just after they were discontinued in 2005/6. Had to email a
number of suppliers until I found the second one. I bet there are some
still in storage somewhere, email different places that sell Winegard,
you may still find one.
John K9RZZ

Twice the signal means twice the voltage, for me.
Greg

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.
Greg

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your units of
measure, you wouldn't be having such problems.

You've got it backwards, Jeff. Twice the voltage is 4 times the power.
1.414 times the voltage would be twice the power.

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:
If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.


I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas with two
transmitters. Two antennas, one transmitter, with one splitter would only
give 3 dB power increase at the receiver. I'm just thinking out loud. I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg


No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but who
cares about the laws of physics? :)

The reason big speaker systems work in large places is efficiency gain
using multiple arrays, must be in phase. As I was saying, it's a known
fact, which I have measured. You can actually get near 10 dB gain using
several speakers. It's why horn loudspeakers have gain, better impedance
matching to air.

I once believed two in phase speakers provided 3 dB increase also. I then
read a speaker project by the now famous diAppolito configuration designer
in Speaker Builder magazine 80's ?. I can try to find a reference.

Greg