S
Stu jaxon
Guest
Hi Group, can someone help please, I have an antenna booster that requires a power supply of 6v 100ma, can i use a variable power supply 6v 300ma???
Thanks,
Thanks,
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Dave Platt
Guest
Stu jaxon <stankowalski02@gmail.com> wrote:
Assuming that they\'re both DC supplies, and assuming that you get the
polarity correct (positive-supply to positive-load, negative-supply to
negative-load), and assuming that you\'re careful to not turn the
variable power supply up to higher than 6 volts... yes, it should
work. The 300 mA capacity of the variable supply is greater than the
100 mA which the booster will draw, and that\'s OK. However, turning
up the supply to above 6 volts may damage the booster. I\'d recommend
checking the supply voltage with a voltmeter before you connect it to
the booster.
Do be aware that \"antenna booster\" amplifiers can cause more problems
than they solve. In most cases you\'ll get better results by improving
your antenna setup.
Hi Group, can someone help please, I have an antenna booster that requires a power supply of 6v 100ma, can i use a
variable power supply 6v 300ma???
Assuming that they\'re both DC supplies, and assuming that you get the
polarity correct (positive-supply to positive-load, negative-supply to
negative-load), and assuming that you\'re careful to not turn the
variable power supply up to higher than 6 volts... yes, it should
work. The 300 mA capacity of the variable supply is greater than the
100 mA which the booster will draw, and that\'s OK. However, turning
up the supply to above 6 volts may damage the booster. I\'d recommend
checking the supply voltage with a voltmeter before you connect it to
the booster.
Do be aware that \"antenna booster\" amplifiers can cause more problems
than they solve. In most cases you\'ll get better results by improving
your antenna setup.
S
Stu jaxon
Guest
On Tuesday, September 22, 2020 at 5:56:17 PM UTC-4, Dave Platt wrote:
OK, very good. Thanks for that advice.
Stu jaxon <stankow...@gmail.com> wrote:
Hi Group, can someone help please, I have an antenna booster that requires a power supply of 6v 100ma, can i use a
variable power supply 6v 300ma???
Assuming that they\'re both DC supplies, and assuming that you get the
polarity correct (positive-supply to positive-load, negative-supply to
negative-load), and assuming that you\'re careful to not turn the
variable power supply up to higher than 6 volts... yes, it should
work. The 300 mA capacity of the variable supply is greater than the
100 mA which the booster will draw, and that\'s OK. However, turning
up the supply to above 6 volts may damage the booster. I\'d recommend
checking the supply voltage with a voltmeter before you connect it to
the booster.
Do be aware that \"antenna booster\" amplifiers can cause more problems
than they solve. In most cases you\'ll get better results by improving
your antenna setup.
OK, very good. Thanks for that advice.
P
Phil Allison
Guest
Dave Platt wrote:
-----------------------
** Unless you need to run multiple co-ax lines from your antenna, such boosters are a useless scam.
I could only laugh at folk I saw buying them to *fix* the lousy pic that was
coming from an indoor antenna in analogue days - and scowl at the ignorant pigs who supplied them for that purpose.
This are not different now.
...... Phil
-----------------------
Do be aware that \"antenna booster\" amplifiers can cause more problems
than they solve. In most cases you\'ll get better results by improving
your antenna setup.
** Unless you need to run multiple co-ax lines from your antenna, such boosters are a useless scam.
I could only laugh at folk I saw buying them to *fix* the lousy pic that was
coming from an indoor antenna in analogue days - and scowl at the ignorant pigs who supplied them for that purpose.
This are not different now.
...... Phil
R
Ralph Mowery
Guest
In article <338b70aa-3da9-485f-a392-b1ab4aee6014o@googlegroups.com>,
stankowalski02@gmail.com says...
I agree with Dave.
It does not matter what the current rating of a supply ( as long as it
is equal to or greater than what is needed by the device) is if it puts
out the required voltage and not more.
Some wall cubes will be listed at one voltage, but with a much lighter
load will put out much more voltage.
Just think of a voltage regulated supply like your house wiring. Many
circuits are either 15 or 20 amps, but supply less than a tenth of an
amp that many wall cubes and night lights use. Even the newer LED light
bulbs only pull slightly more current than that.
A device that is working properly will only draw the ammount of current
needed.
stankowalski02@gmail.com says...
Hi Group, can someone help please, I have an antenna booster that requires a power supply of 6v 100ma, can i use a variable power supply 6v 300ma???
I agree with Dave.
It does not matter what the current rating of a supply ( as long as it
is equal to or greater than what is needed by the device) is if it puts
out the required voltage and not more.
Some wall cubes will be listed at one voltage, but with a much lighter
load will put out much more voltage.
Just think of a voltage regulated supply like your house wiring. Many
circuits are either 15 or 20 amps, but supply less than a tenth of an
amp that many wall cubes and night lights use. Even the newer LED light
bulbs only pull slightly more current than that.
A device that is working properly will only draw the ammount of current
needed.
P
Pimpom
Guest
On 9/23/2020 3:26 AM, Dave Platt wrote:
antenna booster is the only way to get an acceptable reception.
TV came to this remote corner of India in 1980 when some army
people discovered that it was possible to receive stations in
neighbouring Bangladesh. Due to the very hilly terrain, reception
varied from fair to unusable within tens of meters, all with
outdoor yagi antennas. Antenna boosters were a must.
The boosters were all alike, made up of 4 or 5 bjt amplifier
stages. Power was fed to the booster via twin 300-ohm cable from
an indoor 12V AC supply and gain was adjusted by means of a
series potentiometer.
I was the local \"expert\" and I experimented with different
antenna types, including yagi arrays and helical antennas with a
6-foot plane reflector. Some people claimed that reception was
noticeably improved by hanging aluminium pans on their yagis.
Agreed on all points except that, in certain situations, using anStu jaxon <stankowalski02@gmail.com> wrote:
Hi Group, can someone help please, I have an antenna booster that requires a power supply of 6v 100ma, can i use a
variable power supply 6v 300ma???
Assuming that they\'re both DC supplies, and assuming that you get the
polarity correct (positive-supply to positive-load, negative-supply to
negative-load), and assuming that you\'re careful to not turn the
variable power supply up to higher than 6 volts... yes, it should
work. The 300 mA capacity of the variable supply is greater than the
100 mA which the booster will draw, and that\'s OK. However, turning
up the supply to above 6 volts may damage the booster. I\'d recommend
checking the supply voltage with a voltmeter before you connect it to
the booster.
Do be aware that \"antenna booster\" amplifiers can cause more problems
than they solve. In most cases you\'ll get better results by improving
your antenna setup.
antenna booster is the only way to get an acceptable reception.
TV came to this remote corner of India in 1980 when some army
people discovered that it was possible to receive stations in
neighbouring Bangladesh. Due to the very hilly terrain, reception
varied from fair to unusable within tens of meters, all with
outdoor yagi antennas. Antenna boosters were a must.
The boosters were all alike, made up of 4 or 5 bjt amplifier
stages. Power was fed to the booster via twin 300-ohm cable from
an indoor 12V AC supply and gain was adjusted by means of a
series potentiometer.
I was the local \"expert\" and I experimented with different
antenna types, including yagi arrays and helical antennas with a
6-foot plane reflector. Some people claimed that reception was
noticeably improved by hanging aluminium pans on their yagis.
P
Pimpom
Guest
On 9/23/2020 1:02 PM, Pimpom wrote:
pair of yagis on a hilltop for a client who had no reception at
all in his house which was located on the blind side of the hill.
It worked somewhat but was not really satisfactory.
What I couldn\'t really explain was that reception slowly but
steadily degraded in the decade from 1980 to 1990 (when cable TV
arrived). In 1980, I could often get excellent reception in my
house with literally an aluminium coat hanger plugged into the
antenna socket. By contrast, I could watch the 1990 FIFA World
Cup only with an array of four yagis *and* an antenna booster.
Once I even rigged up a passive re-radiator with a back-to-backOn 9/23/2020 3:26 AM, Dave Platt wrote:
Stu jaxon <stankowalski02@gmail.com> wrote:
Hi Group, can someone help please, I have an antenna booster that requires a power supply of 6v 100ma, can i use a
variable power supply 6v 300ma???
Assuming that they\'re both DC supplies, and assuming that you get the
polarity correct (positive-supply to positive-load, negative-supply to
negative-load), and assuming that you\'re careful to not turn the
variable power supply up to higher than 6 volts... yes, it should
work. The 300 mA capacity of the variable supply is greater than the
100 mA which the booster will draw, and that\'s OK. However, turning
up the supply to above 6 volts may damage the booster. I\'d recommend
checking the supply voltage with a voltmeter before you connect it to
the booster.
Do be aware that \"antenna booster\" amplifiers can cause more problems
than they solve. In most cases you\'ll get better results by improving
your antenna setup.
Agreed on all points except that, in certain situations, using an
antenna booster is the only way to get an acceptable reception.
TV came to this remote corner of India in 1980 when some army
people discovered that it was possible to receive stations in
neighbouring Bangladesh. Due to the very hilly terrain, reception
varied from fair to unusable within tens of meters, all with
outdoor yagi antennas. Antenna boosters were a must.
The boosters were all alike, made up of 4 or 5 bjt amplifier
stages. Power was fed to the booster via twin 300-ohm cable from
an indoor 12V AC supply and gain was adjusted by means of a
series potentiometer.
I was the local \"expert\" and I experimented with different
antenna types, including yagi arrays and helical antennas with a
6-foot plane reflector. Some people claimed that reception was
noticeably improved by hanging aluminium pans on their yagis.
pair of yagis on a hilltop for a client who had no reception at
all in his house which was located on the blind side of the hill.
It worked somewhat but was not really satisfactory.
What I couldn\'t really explain was that reception slowly but
steadily degraded in the decade from 1980 to 1990 (when cable TV
arrived). In 1980, I could often get excellent reception in my
house with literally an aluminium coat hanger plugged into the
antenna socket. By contrast, I could watch the 1990 FIFA World
Cup only with an array of four yagis *and* an antenna booster.
P
Phil Allison
Guest
Pimpom wrote:
--------------
\"Antenna boosters\" are not the same thing, only meant for indoor use.
..... Phil
--------------
Agreed on all points except that, in certain situations, using an
antenna booster is the only way to get an acceptable reception.
TV came to this remote corner of India in 1980 when some army
people discovered that it was possible to receive stations in
neighbouring Bangladesh. Due to the very hilly terrain, reception
varied from fair to unusable within tens of meters, all with
outdoor yagi antennas. Antenna boosters were a must.
The boosters were all alike, made up of 4 or 5 bjt amplifier
stages. Power was fed to the booster via twin 300-ohm cable from
an indoor 12V AC supply and gain was adjusted by means of a
series potentiometer.
** You are describing a dedicated \"mast head amplifier\" which do work well with weak signals.
\"Antenna boosters\" are not the same thing, only meant for indoor use.
..... Phil
P
Pimpom
Guest
On 9/23/2020 5:02 PM, Phil Allison wrote:
called \'antenna boosters\' over here - in popular usage, on the
package and sometimes on the unit itself. I didn\'t know that the
latter term is reserved for indoor units elsewhere.
I\'m familiar with the term \'masthead amplifier\' but they\'re allPimpom wrote:
--------------
Agreed on all points except that, in certain situations, using an
antenna booster is the only way to get an acceptable reception.
TV came to this remote corner of India in 1980 when some army
people discovered that it was possible to receive stations in
neighbouring Bangladesh. Due to the very hilly terrain, reception
varied from fair to unusable within tens of meters, all with
outdoor yagi antennas. Antenna boosters were a must.
The boosters were all alike, made up of 4 or 5 bjt amplifier
stages. Power was fed to the booster via twin 300-ohm cable from
an indoor 12V AC supply and gain was adjusted by means of a
series potentiometer.
** You are describing a dedicated \"mast head amplifier\" which do work well with weak signals.
\"Antenna boosters\" are not the same thing, only meant for indoor use.
called \'antenna boosters\' over here - in popular usage, on the
package and sometimes on the unit itself. I didn\'t know that the
latter term is reserved for indoor units elsewhere.
P
Phil Allison
Guest
Stu jaxon wrote:
----------------------
** Did I hear someone say \"antennae booster\" ??
https://allyouneedisbiology.wordpress.com/2018/06/10/insects-antennae/
..... Phil
----------------------
Hi Group, can someone help please,
** Did I hear someone say \"antennae booster\" ??
https://allyouneedisbiology.wordpress.com/2018/06/10/insects-antennae/
..... Phil
R
Ron D.
Guest
masthead amplifiers generally need a power injector which might have coax in coax out and a port for power. The amp is on the mast.
Other amplifiers may just need a power source and are not remotely mounted.
I\'m currently using a channel master CM-7777 at the mast with an 18db amp in the attic with an attenuator, so 0-18db. i think the CM-7777 is defective. For distribution to about 12 locations I was using a 30-45db amplifier until it went south. Currently distributing the signal to two locations.
Other amplifiers may just need a power source and are not remotely mounted.
I\'m currently using a channel master CM-7777 at the mast with an 18db amp in the attic with an attenuator, so 0-18db. i think the CM-7777 is defective. For distribution to about 12 locations I was using a 30-45db amplifier until it went south. Currently distributing the signal to two locations.
P
Phil Allison
Guest
Pimpom wrote:
============
I soon discovered \"Indian English\" differs from mine in numerous way - we regularly wind up speaking at cross purposes cos they apply different meanings to everyday words. She also spends hours each day staring at her I-phone so picks up lots of Americanisms.
For instance - they had no idea what Styrofoam was cos their name for it is \"Thermocol\". It\'s hard for them to believe their English is actually a bit odd as they only socialise with other Indians.
..... Phil
============
** You are describing a dedicated \"mast head amplifier\" which do work well with weak signals.
\"Antenna boosters\" are not the same thing, only meant for indoor use.
I\'m familiar with the term \'masthead amplifier\' but they\'re all
called \'antenna boosters\' over here - in popular usage, on the
package and sometimes on the unit itself. I didn\'t know that the
latter term is reserved for indoor units elsewhere.
** I have Indian neighbours from Hyderabad - he\'s an IT expert and she a stay at home mom.
I soon discovered \"Indian English\" differs from mine in numerous way - we regularly wind up speaking at cross purposes cos they apply different meanings to everyday words. She also spends hours each day staring at her I-phone so picks up lots of Americanisms.
For instance - they had no idea what Styrofoam was cos their name for it is \"Thermocol\". It\'s hard for them to believe their English is actually a bit odd as they only socialise with other Indians.
..... Phil
C
Clifford Heath
Guest
On 24/9/20 10:17 am, Phil Allison wrote:
Indian English is a recognised variety of English. Not even definitely a
dialect, as it has its own grammar in some cases, which can be argued to
make it a distinct language (as e.g. Schweizerdeutsch is a distinct
language, not merely a dialect of German).
<https://en.wikipedia.org/wiki/Indian_English>
CH
Pimpom wrote:
=============
** You are describing a dedicated \"mast head amplifier\" which do work well with weak signals.
\"Antenna boosters\" are not the same thing, only meant for indoor use.
I\'m familiar with the term \'masthead amplifier\' but they\'re all
called \'antenna boosters\' over here - in popular usage, on the
package and sometimes on the unit itself. I didn\'t know that the
latter term is reserved for indoor units elsewhere.
** I have Indian neighbours from Hyderabad - he\'s an IT expert and she a stay at home mom.
I soon discovered \"Indian English\" differs from mine in numerous way - we regularly wind up speaking at cross purposes cos they apply different meanings to everyday words. She also spends hours each day staring at her I-phone so picks up lots of Americanisms.
For instance - they had no idea what Styrofoam was cos their name for it is \"Thermocol\". It\'s hard for them to believe their English is actually a bit odd as they only socialise with other Indians.
Indian English is a recognised variety of English. Not even definitely a
dialect, as it has its own grammar in some cases, which can be argued to
make it a distinct language (as e.g. Schweizerdeutsch is a distinct
language, not merely a dialect of German).
<https://en.wikipedia.org/wiki/Indian_English>
CH
J
Jeff Liebermann
Guest
On Wed, 23 Sep 2020 17:56:57 +0530, Pimpom <nobody@nowhere.com> wrote:
In cellular service, it\'s called a TMA (tower mounted amplifier):
<https://en.wikipedia.org/wiki/Tower_Mounted_Amplifier>
If the downlink is via RF instead of coaxial cable, it might be
considered an \"active repeater\":
<https://encyclopedia2.thefreedictionary.com/Active+Repeater>
There is also a \"passive repeater\" which functions in the same manner
using two antennas, but lacks a powered amplifier. If the downlink
coax cable or RF path operates on a different channel than the receive
signal, it\'s a \"TV translator\".
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
On 9/23/2020 5:02 PM, Phil Allison wrote:
Pimpom wrote:
--------------
Agreed on all points except that, in certain situations, using an
antenna booster is the only way to get an acceptable reception.
TV came to this remote corner of India in 1980 when some army
people discovered that it was possible to receive stations in
neighbouring Bangladesh. Due to the very hilly terrain, reception
varied from fair to unusable within tens of meters, all with
outdoor yagi antennas. Antenna boosters were a must.
The boosters were all alike, made up of 4 or 5 bjt amplifier
stages. Power was fed to the booster via twin 300-ohm cable from
an indoor 12V AC supply and gain was adjusted by means of a
series potentiometer.
** You are describing a dedicated \"mast head amplifier\" which do work well with weak signals.
\"Antenna boosters\" are not the same thing, only meant for indoor use.
I\'m familiar with the term \'masthead amplifier\' but they\'re all
called \'antenna boosters\' over here - in popular usage, on the
package and sometimes on the unit itself. I didn\'t know that the
latter term is reserved for indoor units elsewhere.
In cellular service, it\'s called a TMA (tower mounted amplifier):
<https://en.wikipedia.org/wiki/Tower_Mounted_Amplifier>
If the downlink is via RF instead of coaxial cable, it might be
considered an \"active repeater\":
<https://encyclopedia2.thefreedictionary.com/Active+Repeater>
There is also a \"passive repeater\" which functions in the same manner
using two antennas, but lacks a powered amplifier. If the downlink
coax cable or RF path operates on a different channel than the receive
signal, it\'s a \"TV translator\".
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
J
Jeff Liebermann
Guest
On Wed, 23 Sep 2020 13:58:54 -0700 (PDT), \"Ron D.\"
<ron.dozier@gmail.com> wrote:
Masthead amps make good targets for lightning hits. I\'ve seen a few
where every semiconductor in the amp was fried.
The CM-7778 has 16dB gain:
<https://www.channelmaster.com/TV_Antenna_Preamplifier_p/cm-7778v3.htm>
while the CM-7777 has 26dB gain:
<https://www.channelmaster.com/TV_Antenna_Preamplifier_p/cm-7777v3.htm>
Also see the CM-7777HD (adjustable gain) and the CM-7778HD
(distribution amp).
This might help:
\"CM-7777, CM-7778 Titan 2 & CM-7778HD detailed troubleshooting.\"
<https://support.channelmaster.com/hc/en-us/articles/360002548994-CM-7777-CM-7778-Titan-2-CM-7778HD-detailed-troubleshooting-CM7777-CM7778->
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
<ron.dozier@gmail.com> wrote:
masthead amplifiers generally need a power injector which might have coax in coax out and a port for power. The amp is on the mast.
Other amplifiers may just need a power source and are not remotely mounted.
I\'m currently using a channel master CM-7777 at the mast with an 18db amp in the attic with an attenuator, so 0-18db. i think the CM-7777 is defective. For distribution to about 12 locations I was using a 30-45db amplifier until it went south. Currently distributing the signal to two locations.
Masthead amps make good targets for lightning hits. I\'ve seen a few
where every semiconductor in the amp was fried.
The CM-7778 has 16dB gain:
<https://www.channelmaster.com/TV_Antenna_Preamplifier_p/cm-7778v3.htm>
while the CM-7777 has 26dB gain:
<https://www.channelmaster.com/TV_Antenna_Preamplifier_p/cm-7777v3.htm>
Also see the CM-7777HD (adjustable gain) and the CM-7778HD
(distribution amp).
This might help:
\"CM-7777, CM-7778 Titan 2 & CM-7778HD detailed troubleshooting.\"
<https://support.channelmaster.com/hc/en-us/articles/360002548994-CM-7777-CM-7778-Titan-2-CM-7778HD-detailed-troubleshooting-CM7777-CM7778->
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
P
Phil Allison
Guest
Clifford Heath wrote:
==================> Phil Allison wrote:
** Sure - as typically spoken in India, you see it on TV, movies etc.
But educated folk, living outside India for many years lose most of those idiosyncrasies. Tricks you into thinking they have left them behind.
Conversations with them are fun but always fairly short. You soon run into a language /cultural dead end. Big shame.
...... Phil
==================> Phil Allison wrote:
** I have Indian neighbours from Hyderabad - he\'s an IT expert and she a stay at home mom.
I soon discovered \"Indian English\" differs from mine in numerous way - we regularly wind up speaking at cross purposes cos they apply different meanings to everyday words. She also spends hours each day staring at her I-phone so picks up lots of Americanisms.
For instance - they had no idea what Styrofoam was cos their name for it is \"Thermocol\". It\'s hard for them to believe their English is actually a bit odd as they only socialise with other Indians.
Indian English is a recognised variety of English.
** Sure - as typically spoken in India, you see it on TV, movies etc.
But educated folk, living outside India for many years lose most of those idiosyncrasies. Tricks you into thinking they have left them behind.
Conversations with them are fun but always fairly short. You soon run into a language /cultural dead end. Big shame.
...... Phil
P
pfjw@aol.com
Guest
Two peoples separated by a common language.
George Bernard Shaw
George Bernard Shaw
D
Dave Platt
Guest
In article <56unmfhd8j3h69650rfhu107426r70pj2n@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:
Yeah... probably need to consider them to be a potentially-sacrificial
component.
The really troublesome ones I\'ve heard/read about, are the
cheapies... sometimes using just a single broadband transistor as a
gain element. Some of these have been known to break into
oscillation, for some reason (or no reason) and blast broadband noise
all over the place.
https://www.gpsworld.com/the-hunt-rfi/#:~:text=Reports%20of%20other%20GPS%20users,narrow%20harbor%20entrance%20in%20fog.
talks about one such case, in which several on-shipboard \"active TV
antenna\" systems were emitting enough RF crud to blank out GPS
reception in the harbor in Moss Landing, CA. Not a good thing to lose
your GPS when you\'re trying to come into a foggy harbor at night.
This is one reason why which buying a well-tested, professional-grade
mast-head amplifier would probably be a better idea than buying a
generic cheapie.
Jeff Liebermann <jeffl@cruzio.com> wrote:
Masthead amps make good targets for lightning hits. I\'ve seen a few
where every semiconductor in the amp was fried.
Yeah... probably need to consider them to be a potentially-sacrificial
component.
The really troublesome ones I\'ve heard/read about, are the
cheapies... sometimes using just a single broadband transistor as a
gain element. Some of these have been known to break into
oscillation, for some reason (or no reason) and blast broadband noise
all over the place.
https://www.gpsworld.com/the-hunt-rfi/#:~:text=Reports%20of%20other%20GPS%20users,narrow%20harbor%20entrance%20in%20fog.
talks about one such case, in which several on-shipboard \"active TV
antenna\" systems were emitting enough RF crud to blank out GPS
reception in the harbor in Moss Landing, CA. Not a good thing to lose
your GPS when you\'re trying to come into a foggy harbor at night.
This is one reason why which buying a well-tested, professional-grade
mast-head amplifier would probably be a better idea than buying a
generic cheapie.
J
Jeff Liebermann
Guest
On Thu, 24 Sep 2020 13:41:43 -0700, dplatt@coop.radagast.org (Dave
Platt) wrote:
I had one mounted on a redwood tree. It wasn\'t hit by lightning.
Instead, it was invaded by ants, dripping formic acid, which ate the
copper traces on the PCB. I was prepared to replace all the active
components, but not the entire amplifier.
This might fill in a few details:
<http://www.learnbydestroying.com/jeffl/GPS%20Jamming%20Moss%20Landing/>
Note the photo of the antenna. The cloverleaf pattern is NOT a
broadband device and will not present a 75 ohm impedance to the
amplifier input. Designing a broadband amplifier to be
unconditionally stable and provide a low NF (noise figure) as well as
high gain into such an antenna is difficult. There will be some
frequency, where the antenna presents the perfect impedance to cause
the amplifier to oscillate. Also, such an antenna construction is not
very tolerant of the corrosive effects of a marine environment and
probably should have been potted or conformal coated.
Yep. That happened near me. Although I knew some of the
participants, I didn\'t know that there had been a transmitter hunt
until two years after it was over and the article appeared in GSP
World.
GPS selective availability was finally turned off on May 1, 2000,
navigating a 150 ft wide harbor entrance channel by GPS would have
been theoretically possible. At the time, MBARI did operate their own
DGPS transmitter on Mt Toro, but that was for precision vessel and
buoy location in the bay. Today, even with WAAS, GALILEO and GLONAS
satellites added to improve GPS precision, I\'m told it\'s still tricky
due to reflections from moving metal masts and rigging, plus a very
large steel building at the power plant. Once into the channel, I
would probably switch to navigating by the harbor lights:
<https://geographic.org/nautical_charts/map_img/18685_3-t.png>
Yep. In my never humble opinion, there was probably nothing wrong
with the amplifier. Instead, it was the design of the antenna, which
had the misfortune of not being properly matched to the RF amplifier
causing the amp to oscillate. A properly designed Yagi, Bow-Tie,
LPDA (log periodic dipole array), or other broadband design, would
worked better, and not oscillated.
<http://www.hdtvprimer.com/ANTENNAS/comparing.html>
<http://www.hdtvprimer.com/SIMS/>
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Platt) wrote:
In article <56unmfhd8j3h69650rfhu107426r70pj2n@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:
Masthead amps make good targets for lightning hits. I\'ve seen a few
where every semiconductor in the amp was fried.
Yeah... probably need to consider them to be a potentially-sacrificial
component.
I had one mounted on a redwood tree. It wasn\'t hit by lightning.
Instead, it was invaded by ants, dripping formic acid, which ate the
copper traces on the PCB. I was prepared to replace all the active
components, but not the entire amplifier.
The really troublesome ones I\'ve heard/read about, are the
cheapies... sometimes using just a single broadband transistor as a
gain element. Some of these have been known to break into
oscillation, for some reason (or no reason) and blast broadband noise
all over the place.
https://www.gpsworld.com/the-hunt-rfi/#:~:text=Reports%20of%20other%20GPS%20users,narrow%20harbor%20entrance%20in%20fog.
This might fill in a few details:
<http://www.learnbydestroying.com/jeffl/GPS%20Jamming%20Moss%20Landing/>
Note the photo of the antenna. The cloverleaf pattern is NOT a
broadband device and will not present a 75 ohm impedance to the
amplifier input. Designing a broadband amplifier to be
unconditionally stable and provide a low NF (noise figure) as well as
high gain into such an antenna is difficult. There will be some
frequency, where the antenna presents the perfect impedance to cause
the amplifier to oscillate. Also, such an antenna construction is not
very tolerant of the corrosive effects of a marine environment and
probably should have been potted or conformal coated.
talks about one such case, in which several on-shipboard \"active TV
antenna\" systems were emitting enough RF crud to blank out GPS
reception in the harbor in Moss Landing, CA.
Yep. That happened near me. Although I knew some of the
participants, I didn\'t know that there had been a transmitter hunt
until two years after it was over and the article appeared in GSP
World.
Not a good thing to lose
your GPS when you\'re trying to come into a foggy harbor at night.
GPS selective availability was finally turned off on May 1, 2000,
navigating a 150 ft wide harbor entrance channel by GPS would have
been theoretically possible. At the time, MBARI did operate their own
DGPS transmitter on Mt Toro, but that was for precision vessel and
buoy location in the bay. Today, even with WAAS, GALILEO and GLONAS
satellites added to improve GPS precision, I\'m told it\'s still tricky
due to reflections from moving metal masts and rigging, plus a very
large steel building at the power plant. Once into the channel, I
would probably switch to navigating by the harbor lights:
<https://geographic.org/nautical_charts/map_img/18685_3-t.png>
This is one reason why which buying a well-tested, professional-grade
mast-head amplifier would probably be a better idea than buying a
generic cheapie.
Yep. In my never humble opinion, there was probably nothing wrong
with the amplifier. Instead, it was the design of the antenna, which
had the misfortune of not being properly matched to the RF amplifier
causing the amp to oscillate. A properly designed Yagi, Bow-Tie,
LPDA (log periodic dipole array), or other broadband design, would
worked better, and not oscillated.
<http://www.hdtvprimer.com/ANTENNAS/comparing.html>
<http://www.hdtvprimer.com/SIMS/>
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
C
Chris K-Man
Guest
On Tuesday, September 22, 2020 at 4:54:39 PM UTC-4, Stu jaxon wrote:
> Hi Group, can someone help please, I have an antenna booster
that requires a power supply of 6v 100ma, can i use a variable power
supply 6v 300ma???
My idea of a \"booster\" or \"signal amp\" is a bigger/higher gain antenna.
As far as language differences are concerned, England and India are
forever bound by their use of English. Compared to them, what is spoken
in the States is called AMERICAN: a rebellious corruption and bastardisation
of what is spoken/written in the two aforementioned nations.
Where else do you hear \"nucular\" routinely substitute for nuclear? Or
plural\'s of item\'s succeeded with an apostrphe s? LOL!
> Hi Group, can someone help please, I have an antenna booster
that requires a power supply of 6v 100ma, can i use a variable power
supply 6v 300ma???
Thanks,
____________
My idea of a \"booster\" or \"signal amp\" is a bigger/higher gain antenna.
As far as language differences are concerned, England and India are
forever bound by their use of English. Compared to them, what is spoken
in the States is called AMERICAN: a rebellious corruption and bastardisation
of what is spoken/written in the two aforementioned nations.
Where else do you hear \"nucular\" routinely substitute for nuclear? Or
plural\'s of item\'s succeeded with an apostrphe s? LOL!