The guy did ok on the first part explaining how power factor works but fell
down when it comes to the save money part.
The utilities do not charge you extra or give you a break if you do or don't
have any power factor correction. Unless you are an industrial customer.
I have seen
You won't see any difference. The electric meter reads true power not VA.
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
Sent: Friday, August 20, 2010 8:00 PM
To:
Here is a little primer on lightning:
Having your antenna grounded does not drain off any charge that helps
prevent a strike. As a matter of fact grounding the antenna makes it
slightly more prone to a strike but not grounding it is much worse as you
have no control over what path the energy
Russ,
Of course the Bird 43 does not measure power directly. But it does sample
voltage AND current on the line in amounts that are combined to indicate
power.
It is a directional coupler. The only time you will have a problem with it
deviating from its accuracy is when the directivity
Certainly not bad for a portable instrument, and that's the point. If we
remember what its limitations are, we should be good to go. That's why I
own one and want more.
Okay, I'm done picking nits. It's the next yahoo's turn. ;-)
73, Russ WB8ZCC
On 8/15/2010 2:08 PM, Gary Schafer wrote
, August 15, 2010 7:37 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Coax length, etc.
Last round. Hi again, Gary. ;-)
On 8/15/2010 7:09 PM, Gary Schafer wrote:
Hi again Russ,
_
From: mailto:Repeater-Builder@yahoogroups.com
Repeater-Builder
One correction here; the Bird power meter is not just a voltage measuring
meter. It does in fact measure voltage and current to calculate power. It
will give true power even if used in a non 50 ohm circuit. But you must
always subtract reflected power from indicated forward power to find true
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Jeff DePolo
Sent: Saturday, August 14, 2010 10:45 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Coax length, etc.
Jeff, you aren't
Hi Allan,
Do we really care what the output impedance of the transmitter is? Most
transmitters do not present a pure 50 ohm output but are tuned to transfer
maximum power into a 50 ohm load. This often comes out to something way
different than a 50 ohm source impedance.
As the source
It sounds like you have a linear amplifier. Linear amplifiers are used
when multiple low power transmitters are to be amplified by one amplifier.
The peak power (actually peak envelope power) capability of the amplifier
must be quite high in order to handle the multiple signals without
generating
: how far
i am using BIRD watt meater with 1000 watt slug and i am not
misdirectioning anybody
--- In Repeater-Builder@yahoogroups.com, Gary Schafer gascha...@...
wrote:
It sounds like you have a linear amplifier. Linear amplifiers are
used
when multiple low power transmitters
Just for grins, find a place (house) to hook your spectrum analyzer up to
the local cable system and see if it is on there.
73
Gary K4FMX
_
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike Besemer (WM4B)
Sent: Saturday, April 24,
Subject: [Repeater-Builder] Sineman/Gary Schafer
Did you get the e-mail of the Sineman brochure or do I have a wrong e-
mail addy?
Gary: The guy that marketed that 40 db power pad was actually a rep,
a real character. I still have the data sheet and picture somewhere
here in my library. He used to tell me his real money came from
making and selling waders.
BTW I do have the schematic and JPEG of the Cushman 40 db
The idea of the dual meter unit was to be able to quickly go thru a circuit
without having to touch the meter to change ranges or change to AC or DC. If
you stuck it on a DC circuit it would read that right. If you stuck it on an
AC circuit it would read that.
Also you could read an AC voltage
it
if anyone is interested.
--- In Repeater-Builder@yahoogroups.com, Gary Schafer gascha...@...
wrote:
The idea of the dual meter unit was to be able to quickly go thru a
circuit
without having to touch the meter to change ranges or change to AC or
DC. If
you stuck it on a DC
That was an auto ranging voltmeter. They were rather expensive at the time,
compared to nowadays. As I remember it you could select auto range, or lock
it in a particular range.
73
Gary K4FMX
-Original Message-
From: Alicia Mehrdad [mailto:abcza...@gmail.com]
Sent: Wednesday, March
? Are there any pics?
While we're at it, what ever happened to the watt meter that fed a power
pad like a termaline with an attenuated output? Was that talk, or did
they ever do anything with that?
--- In Repeater-Builder@yahoogroups.com, Gary Schafer gascha...@...
wrote:
That was an auto
Hi Tony,
Yes I remember them! They had some similar products to what Helper
Instruments built and Automated Industrial electronics (AIE) run by Tony
Crady in North Carolina. AIE later bought out the remains of the
Measurements Corp.
As I remember GAW did private label some products for Motorola
displays instead of meters. Batesburg, Va. Wasn't it?
Never heard anything about them after that.
--- In Repeater-Builder@yahoogroups.com, Gary Schafer gascha...@...
wrote:
Hi Tony,
Yes I remember them! They had some similar products to what Helper
Instruments built and Automated
Marine epoxy paint.
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Tim - WD6AWP
Sent: Wednesday, March 17, 2010 11:38 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Antenna Paint
_
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jack Davis
Sent: Wednesday, March 17, 2010 1:15 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Copper pipe rather than 2/0 copper wire
/17/2010 12:11 PM, Gary Schafer wrote:
5/8 OD gives you 1.96 inches (5/8 x 3.14) of surface area. 1 inch
copper
strap gives 2 inches of surface area.
2 inch copper strap gives you 4 inches surface area. Copper strap
should be
less expensive than copper tubing.__,_._,__
Why would you
...@yahoogroups.com] On Behalf Of Gary Schafer
Sent: Wednesday, March 17, 2010 3:39 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Copper pipe rather than 2/0 copper
wire
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil
to gamble on insurance covering a station using
flattened copper pipe as a grounding solution.
- Original Message -
From: Gary Schafer mailto:gascha...@comcast.net
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, March 17, 2010 11:11 AM
Subject: RE: [Repeater-Builder] Re: Copper
Copper strap is better as you get the benefit of both sides of the copper.
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Jesse Lloyd
Sent: Tuesday, March 16, 2010 11:42 AM
To:
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Gary Schafer
Sent: Tuesday, March 16, 2010 11:59 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Copper pipe rather than 2/0 copper wire
Copper strap is better as you get the benefit of both sides of the copper.
73
This is a resend of my email to Nate last night. It looks like good old
yahoo stripped my reply.
Hi Nate,
A UHF pass band cavity for example will pass only a UHF frequency that it is
tuned for. On frequency signals coming into it will see 50 ohms. Off
frequency signals will see a short circuit
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of wd8chl
Sent: Tuesday, March 09, 2010 11:07 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Dual receivers on one antenna for RX
only site
As far as phasing the antennas around the tower, it can't be done. Well it
can but you will end up with more nulls and a worse pattern than you started
with.
The problem is that most signals will arrive at more than one antenna.
Because they are different distances apart to the mobile there will
Well yes the T is sort of a magical device that makes the OTHER SIDE of the
T disappear electrically. Actually it is not the T itself that does the job
(that is just where IT happens) but it is the quarter wave length cables
that perform the magic!
Without the quarter wave length cables
Quarter wave length cables are the thing to use to couple the cavities
together at the antenna connection side of them.
The uhf cavity gets a cable that is a quarter wave length at the VHF
frequency and the VHF cavity gets a cable that is a quarter wave length at
the UHF frequency. These connect
PM, Gary Schafer wrote:
Without the proper length cables between the cavities and the antenna T
connector both UHF and VHF signals will be attenuated depending on the luck
of the cable length.
What technical reason causes this?
Nate
Hi Nate,
A UHF pass band cavity for example will pass
Ok, thanks to all that replied. It looks like it is a 2553 that I need.
Looking at the chart it looks like the CH751 is for the old outdoor cabinet
and the 2553 is for the indoor cabinet.
Also looks like the GE cabinet that I have is probably the desk mate and
takes the LL201 key.
Ted, K9MDM
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Gary Schafer
Sent: Wednesday, February 24, 2010 1:16 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Motorola cabinet key wanted
Ok, thanks to all that replied. It looks like it is a 2553 that I need.
Looking
Don't be too sure about that. Once the am station signal gets into the
receiver it can go anywhere and cause havoc. It could be getting into the IF
or the mixer once picked up by cables.
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
I am in need of a cabinet key for an old Motorola base station cabinet. It
is an old low band 1/4 kw rig. Had 100TH tubes in final. This is the 6 foot
tall cabinet.
Anyone know the key number for these?
Have a key?
Also have an old GE progress line base cabinet that needs a key. This
cabinet is
] On Behalf Of Gary Schafer
Sent: Tuesday, February 23, 2010 6:16 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Motorola cabinet key wanted
I am in need of a cabinet key for an old Motorola base station cabinet. It
is an old low band 1/4 kw rig. Had 100TH tubes in final
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Kris Kirby
Sent: Monday, February 22, 2010 5:03 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: DB-201 Measurements for 6 Meters?
On Mon,
Paul has some good points about batteries.
Here are a few more:
A so called marine deep cycle/starting battery is nothing more than a little
heavier starting battery.
A true deep cycle battery has much larger plates than a starting battery.
A starting battery has thinner plates which allows it
It comes down to where are the IM products really being generated.
I think what Skipp is trying to say is that if the preamp generates spurious
products from overload that fall outside of the center frequency, that
filtering behind the preamp will help keep those products out of the
receiver.
Most of the time you will want as much selectivity as you can get in front
of the preamp. The only time that I can think of off hand where you might
want a filter behind a preamp is if you are getting a receiver feed from a
receiver multicoupler that has a preamp in it, giving a few megs wide
You certainly don't want just any old coax. You for sure don't want any type
of hard line run up the mast as the flexing will break the center
conductor or outer conductor.
You want to have a stranded cable such as RG8 type. Also don't use any type
of foam dielectric type cable on a boat as the
You can make the measurement with a signal generator and a tunable receiver
that has some kind of indicator for signal strength. It doesn't even need to
be calibrated. Connect the signal generator to the antenna port and the
receiver to the receiver port of the duplexer. Be sure to disable the
I don't have a 189 but have other fluke meters. Measuring in dBm, to measure
an absolute value, you must first know what load you are measuring across.
Then the meter must be set up to read zero dBm across that load impedance.
One of the fluke meters that I have has several different settings of
Agreed Rob.
ACSSB is nothing more than regular old SSB with a few things added. The
compandering is simply speech compression on the transmit end and an
equivalent expansion on the receive end to restore the dynamic range of the
voice. This gives some noise reduction in the circuit.
As
Absolutely you need some reserve. The same if you are designing a point to
point path. You don't select equipment that will just do the job. You
always need a certain amount of reserve for changes of equipment etc. the
idea is that some think the repeater is going to work better with more
The reason FM stations transmit circular polarization is to accommodate
both horizontal and vertical receive antennas. Most fixed receivers are
horizontal and most cars are vertical.
You can not transmit both horizontal and vertical polarization at the same
time. Feeding a horizontal antenna
Dan Kagabine, the chief engineer at TX-RX systems use to always say that
once you have enough isolation to overcome any desense, then any more is a
waste of money as it does nothing for you. If you only need 70 db then a
100 db duplexer does nothing more for you than a 70 db duplexer.
73
Gary
Definitions:
Circulator - ferrite device with 3 ports.
Isolator - Circulator with a load on the 3rd port.
Intermod panel - Isolator with a harmonic filter. The harmonic filter may
consist of a 2nd harmonic notch filter or a low pass filter or a band pass
cavity.
73
Gary K4FMX
Actually galvanized and copper plated ground rods should not be mixed in any
ground system. Electrolysis will deplete the plating. All ground rods in any
ground system are electrically connected to one another.
73
Gary k4FMX
_
From: Repeater-Builder@yahoogroups.com
Some lightning facts:
There is no amount of grounding that will help protect an antenna from
lightning damage.
Grounding will not help an antenna or tower from being struck by lightning.
However if a lightning rod is placed above the antenna or a wire sloping
down from above and around the
Receiver gain does not work the same as transmitter power increase. A 10 db
increase in transmitter power is not the equivalent of adding a 10 db preamp
on the receiver. It would be if your receiver was very noisy
(internally)(very poor receiver) to start with and the 10 db preamp overcame
the
Do you have a low pass filter after the isolator?
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of offtrack
Sent: Saturday, May 16, 2009 11:19 AM
To: Repeater-Builder@yahoogroups.com
Subject:
First I would completely remove the external amplifier and connect the
repeater directly to the duplexer. Then turn the power up to where it
belongs on the transmitter. Sounds like the transmitter is generating a
spur.
73
Gary K4FMX
_
From: Repeater-Builder@yahoogroups.com
This is funny. All they appear to be doing is placing a capacitor across the
line at the service panel which gives some power factor correction to motor
or other inductive loads. But that correction is AT THE POWER PANEL which is
only inches or a few feet at the most away from the meter.
If you
Kevin,
I think that you meant the amperage to the load (a motor) is UNCHANGED
with and without the device.
I didn't notice the kwh reading on the meter. Good catch!
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On
No you wouldn't have seen any change in the kwh reading in an hour because
there is no change in real power which is what kwh is. If you were measuring
kva (volt amperes) then that would change.
I would assume that the kwh reading on the (handheld) meter would be
instantaneous.
Otherwise you
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Kevin Custer
Sent: Wednesday, February 11, 2009 8:33 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] OT Power Factor
Gary Schafer wrote
enough, and there was load.
Kevin said that the kWh reading didn't change and didn't understand why.
Chuck
WB2EDV
- Original Message -
From: Gary Schafer gascha...@comcast.net
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, February 11, 2009 8:51 PM
Subject: RE: [Repeater
Your typical home meter measures only real power consumed.
There is no such thing as reactive power being delivered to you. Any
reactive power that you may be concerned with will originate on your side of
the meter at the load. You really don't care about it there either as long
as the extra
The preamp had better amplify all things equally! If it doesn't then it is
non linear and you have an intermod generator connected to your receiver.
But if the preamp is driven hard enough by a strong signal(s) to drive it
into compression then it becomes non linear. A condition that you want to
Hi Nate,
Can't members of the club be held liable as well as officers?
73
Gary K4FMX
_
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Nate Duehr
Sent: Monday, January 26, 2009 8:31 PM
To: Repeater Builder List
Cc:
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf Of Mike Pugh
Sent: Wednesday, January 21, 2009 4:39 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Coax Interconnect (Inside Repeater)
John J.
Hi Skipp,
What's a Helper RF millivoltmeter manual worth to you?
I have one that I will scan for you when I get back home in a couple of
weeks. No charge.
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
buil...@yahoogroups.com] On Behalf
Helper never printed a service manual for the SM512. Only a operators
manual was ever issued. It does have a schematic and some adjustment
information in it.
I have a copy of the manual. I thought I had it with me at my temp qth but I
don't see it. If you will email me after the 1st of the year I
The main reason higher gain antennas on a link are desirable is to narrow
the beam width so that you don't pick up as much or transmit as much
interference to/from undesired stations. Horizontal polarization as
mentioned also helps reduce the interference problems.
73
Gary K4FMX
Mike,
How are you measuring the desense?
How are you connecting the signal generator to the receiver?
What are you using for an indicator of sensitivity on the receiver, sinad,
quieting etc?
I am assuming that you are replacing the antenna line with a dummy load at
the output junction
at the end of
the tee that feeds the feedline. If I do that, I can't feed signal to the
receiver. If I take the TX line off the tee and put a dummy load there,
there is no desense.
Mike
WM4B
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer
Sent: Tuesday
Hi Tom,
As others have said, try the dummy load at the antenna end of the cable and
see if there is any desense.
Then try disconnecting the antenna input to the receiver from the duplexer
and place a dummy load on the receiver. Turn on the transmitter and see if
you still have desense. If
Yes standing waves can exist with a pure resistive load on a line but the
mismatch of the load with the line impedance creates a reactance (depending
on line length).
A transmission line must be long enough (wavelength wise) for standing waves
to exist.
A short line (wavelength wise) like an
I think cables and cavities are being mixed up a littler here. When using
hard line cable to build the cavities for a 6 meter duplexer then that
hard line is not operating as a typical coax line. It is operating as a
quarter wave resonant cavity. It has a high impedance on one end and a short
on
on
Earth, even though you might have a clear line-of-sight path.
73, Eric Lemmon WB6FLY
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer
Sent: Sunday, August 10, 2008 9:20 PM
To: Repeater-Builder@yahoogroups.com
Subject
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Dave Gomberg
Sent: Monday, August 11, 2008 8:37 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Height Gain figure
At 16:42 8/10/2008, Dick wrote:
So if the antenna is already at 1000 feet height and it is moved up another
100 feet to 1100 feet, you are going to increase the range by 14 miles??
73
Gary K4FMX
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Sunday,
If you see several db difference with a 12.5 KHz frequency shift then your
duplexer is also distorting your audio on the transmitted signal. It would
induce unwanted phase shifts and also unwanted amplitude changes in the
transmitted signal.
73
Gary K4FMX
-Original Message-
From:
That is true for band pass filters but in the case of a duplexer the filters
are usually notch type (or pass/notch). So the more notch type cans there
are the wider the notch will be at some given frequency. Think of it as an
upside down band pass response.
Note that the pass response of a
Hi Skipp,
I can't really tell if you are agreeing or disagreeing. :)
A good, properly tuned isolator will absorb all reflected power that is of
any consequence. In other words I don't think that you would be able to see
any reflected power on the wattmeter from the isolator. A wattmeter in line
A couple of notes on this:
Beware of the mfj to read impedance/swr. I have an mfj 259B and it is
terrible on 2 meters. With a GOOD dummy load it shows a higher swr the
higher you go in frequency with it. I think it will show around 1.5:1 and an
impedance of around 42 ohms on the good dummy load.
with that band
often.
I also have noticed the problems in high RF environments, but that's not
MFJ's fault. No SWR bridge works accurately measuring an antenna with a few
milliwatts at a 100 kilowatt broadcast site.
Paul, AE4KR
- Original Message -
From: Gary Schafer mailto
Any tower over 150 feet tall can get a direct hit on the side. It will not
necessarily hit the top of the tower.
A side mounted antenna on a tall tower is not a guarantee that it won't be
hit directly. If a wire is run outside of a side mounted antenna and
connected to the tower above and below
If it were me asking that question, I would be saying thank you to Eric.
Not everyone knows that some of the commercial manufacturers are very
supportive of ham activities and that they have that sort of information
readily available.
73
Gary K4FMX
_
From:
You need a HI-pot tester to check the protection devices. You crank up the
voltage until they show a breakdown and see if it is breaking down at the
proper voltage for the device. It will not harm them at all as the current
is only a few micro amps..
Polyphaser used to market a small test set
Here is a cascade noise figure calculator. Play around with different gain
figures and noise figures for the first amp to see how it affects the total
noise figure. Consider the second amp your receiver. Put in an 8 db or so
figure for the second amp to simulate your receiver.
You will see
For clarification: A SWEEP GENERATOR
is just a sweep generator by itself and is generally used with a diode
detector and a scope to view the output signal of whatever is being swept.
The sensitivity (dynamic range) is limited by the sensitivity of the diode
which is usually in the neighborhood of
Transmitter combiners are not always high loss, avoid like the plague kind
of thing. 10 channels at 250 Khz spacing on 800 does give you quite a hit
but it is still better than the alternative.
The cavity on each transmitter must give at least 10 db of attenuation at
the other frequencies in the
I can't imagine why you would want to put a window filter between your
duplexer and antenna line. There is much more to be gained by putting
separate band pass filters on the tx and rx ports.
In order to make a window filter you need several pass filters in order to
make a wide window. Using
[EMAIL PROTECTED] On Behalf Of skipp025
(window filter cannon fodder)
I can't imagine why you would want to put a window filter
between your duplexer and antenna line. There is much more
to be gained by putting separate band pass filters on the
tx and rx ports.
There can be good
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Daron Wilson
Sent: Thursday, January 31, 2008 9:37 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Desense Problem on 222 MHz Repeater
(window filter cannon fodder)
I
Sorry my last response to this didn't come through.
Additional may be the key word here. I can assure you that a window
filter did not do the job just because it is a window filter.
Pass cavities do not have ultimate rejection off frequency. The skirt goes
down to a certain point and then
How are you checking for desense? Are you using an isolated T between the
duplexer and antenna line and doing the same when measuring desense on the
dummy load?
Are you measuring site noise? Do this the same way you would measure desense
with the isolated T in the line. But first see what the
If you have an extra band pass cavity then you also have a notch cavity.
Just connect a T to one port of the band pass cavity and ignore the other
port on the cavity. This will work as a notch cavity for your testing.
73
Gary K4FMX
_
From: Repeater-Builder@yahoogroups.com
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Ken Arck
Sent: Thursday, January 17, 2008 7:11 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: MSR2000 transmit spike
At 04:06 PM 1/17/2008, you
When inserting the bird meter between the duplexer and the radio make sure
that you have a jumper that you use with the bird meter that makes the meter
and jumper cable a 1/2 wavelength at the frequency of the transmitter.
That way inserting the meter will show the transmitter the same impedance
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Monday, January 14, 2008 11:21 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Revisiting Shorted 1/2-wave Traps
Paul,
You have to account for the velocity factor of the cable. The length you use
has to be the electrical length not the physical length.
This measurement that you made indicates that the cable is a quarter wave
(not ½ wave) at 146.15 if indeed you do have the far end open.
146.15 MHz
amplifier, the output per channel shall work out as
-2dBm (+22dBm - 24dB, and +22dBm is 1dB compression point). However, the
measurement shows that it is -24dBm per channel. Anything we have missed
out?
Best Regards,
Chong Kwan Meng
- Original Message
From: Gary Schafer [EMAIL
If you want each signal, of the 16 signals, to be 0 dBm (1 mW) output
capable then the amplifier has to be capable of 16 squared times 1 mW or 256
milliwatts. This is the peak envelope power that can be present at any one
time in the amplifier with 16 signals present.
So the amplifier would need
I don't know that particular duplexer. The close spacing capability is not
an indication that it is a band pass/band reject or a straight notch type
unit. It could be either.
The difference in the smaller mobile type or smaller rack mount type
duplexers is usually in the insertion loss. The
1 + square root (r/f)
SWR= _
1 - square root (r/f)
where r = reflected power
f = forward power
73
Gary K4FMX
from: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of n9wys
Sent: Wednesday,
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