Today's Message Index:
----------------------
1. 05:27 AM - Re: Are 'serial' contactors really needed? (jon molek)
2. 05:38 AM - Re: Re: Are 'serial' contactors really needed? (jon molek)
3. 07:41 AM - Re: Are 'serial' contactors really needed? (user9253)
4. 08:02 AM - Crowbar OV module placement (Robert L. Nuckolls, III)
5. 09:18 AM - Re: COZY: Phantom audio return path (Narco 12MKE) (Alan Barnett)
6. 10:34 AM - Re: Crowbar OV module placement (jon molek)
7. 10:36 AM - Re: Re: Are 'serial' contactors really needed? (jon molek)
8. 01:29 PM - Transmitting with no antenna? (donjohnston)
9. 01:56 PM - Z13 fusible link, circuit breaker, same circuit? (Bower, Bob)
10. 02:26 PM - Re: Transmitting with no antenna? (Henry Hallam)
11. 02:49 PM - Re: Z13 fusible link, circuit breaker, same circuit? (John Tipton)
12. 02:51 PM - Re: Transmitting with no antenna? (donjohnston)
13. 02:54 PM - Re: Transmitting with no antenna? (John Tipton)
14. 02:58 PM - Re: Z13 fusible link, circuit breaker, same circuit? (Bower, Bob)
15. 02:59 PM - Re: Transmitting with no antenna? (Bill Putney)
16. 03:22 PM - Re: Re: Transmitting with no antenna? (Bill Putney)
17. 03:23 PM - Re: Transmitting with no antenna? (John MacCallum)
18. 06:10 PM - Re: Transmitting with no antenna? (Eric Page)
19. 06:38 PM - Re: Crowbar OV module placement (Robert L. Nuckolls, III)
20. 06:46 PM - Re: Transmitting with no antenna? (Robert L. Nuckolls, III)
Message 1
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Subject: | Re: Are 'serial' contactors really needed? |
yes I'm using the B&C schematic with an external regulator ,(no changes) it says
to hook the ovm to regulator in & to the master switch .
I want to hook it to the field which has a five amp breaker .
I'm asking why I can't do that instead of the regulator in?
Sent from my iPhone
> On Jul 20, 2014, at 4:41 PM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
>
> At 06:13 AM 7/20/2014, you wrote:
>> I tried using five amp breaker it won't kick the alternator in
>> have to have a 60 amp I guess
>>
>> Sent from my iPhone
>
> A picture may be worth 10,000 words . . . but 10,000
> words never describes the same picture in the
> minds of all readers.
>
> Are you wiring to a published schematic that
> we can download and all pray over at the same
> time? If you've modified a published schematic,
> then a scanned copy of your changes will
> offer all of us a reasonable chance of understanding
> your design goals and offering a solution.
>
>
>
> Bob . . .
>
>
>
>
Message 2
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Subject: | Re: Are 'serial' contactors really needed? |
this is an alternator with an external regulator (system by Interav, using their
schematic and B&C schematic ) it's a Motorola Alternator previously installed
an experimental RV8
my intention is to use the field instead of the regulator in ,being how the field
already has a 5 amp breaker to kick ,
(it is also controlling the regulator )
Thank You for your time & advice it's greatly appreciated and very helpful!
John
Sent from my iPhone
> On Jul 20, 2014, at 4:31 PM, "user9253" <fransew@gmail.com> wrote:
>
>
> John,
> Is the O.V. module being installed in an experimental airplane?
> What make and model is it?
> Are we talking about an alternator or dynamo or generator?
> Is there an external voltage regulator?
> Is this an existing electrical system that you are adding an O.V. module to?
> If there is an existing alternator and external voltage regulator, then there
should also be a fuse or circuit breaker that supplies power to the voltage regulator.
The O.V. module needs to be connected between the 5 amp circuit breaker
and the voltage regulator (which is part of the field circuit).
> Good advice can not be given without knowing all of the facts.
> It is better to not install an O.V. module than to install it incorrectly.
>
>> . . . .you may want to refer to my email again for all details thank you !
>
> I can not find your original posting.
>
>> why am I getting everybody's questions and answers to me from other people
>
> Because you are posting in someone else's thread.
>
>>
>> do I still need to change to a voltage limiter on the firewall ?if so what is
it ?
>
> Do you mean current limiter? It is sort of a robust very slow blow fuse.
> Search for MIDI fuse or ANL fuse. A current limiter is a good idea, but is unrelated
to the O.V. module.
>
>> do I split the regulator in or split the field the field has the breaker on
& the regulator in doesn't
>
> Sorry, I do not understand that. If installing an O.V. module to an existing
> electrical system, no splitting is necessary. Connect the O.V. module to the
wire that goes between the 5 amp breaker and the voltage regulator.
> Joe
>
> --------
> Joe Gores
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=427018#427018
>
>
>
>
>
>
>
>
>
>
Message 3
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Subject: | Re: Are 'serial' contactors really needed? |
> it says to hook the ovm to regulator in & to the master switch
No it doesn't.
B&C schematic link: http://www.bandc.biz/pdfs/OVM_wiringdiagram.pdf
The B&C schematic shows the black wire of the O.V. module connected to ground.
They just happened to use the same ground that the master switch is connected
to. You can connect the black wire to any convenient ground.
I think that B&C drew the schematic that way for two reasons: 1. It is easy to
draw. 2. It is easy to wire directly at the master switch because both ground
and the alternator field circuit are available there (if your master switch is
wired like B&C's switch is wired).
As for the colored wire (orange?) of the O.V., B&C shows it connected to the alternator-field
half of the master switch. Electrically speaking, this is the
same as connecting to the voltage regulator input. In either case, power is coming
from the 5 amp breaker.
Now if you want to connect the O.V. module directly to the 5 amp breaker, I see
no reason why that will not work. I hope others will correct me if wrong. Just
make sure that it is connected to the down stream side and not the always
hot side of the breaker.
In summary, connect the O.V. black wire to ground. And connect the other wire
to some point between the 5 amp breaker and the input to the voltage regulator.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=427062#427062
Message 4
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Subject: | Crowbar OV module placement |
At 07:25 AM 7/21/2014, you wrote:
>
>yes I'm using the B&C schematic with an external regulator ,(no
>changes) it says to hook the ovm to regulator in & to the master switch .
>I want to hook it to the field which has a five amp breaker .
>I'm asking why I can't do that instead of the regulator in?
The crowbar ov module functions by creating
a high current (artificial fault) on the field
voltage supply line for the purpose of
forcing the field supply breaker open . . .
thus depriving the alternator of field
excitation an shutting it down.
That 'fault' may be applied anywhere along
the supply line between the breaker and
the regulator's input terminal.
What kind of regulator are you using?
You mentioned something to the effect that
a 5A breaker seemed inadequate to getting
the alternator to come alive? You need
to get the alternator working first using
details from the B&C drawing . . . the
breaker sizes cited are correct.
After the alternator is working, then add
the OV module at any point along the field
excitation power path.
Bob . . .
Message 5
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Subject: | Re: COZY: Phantom audio return path (Narco 12MKE) |
Message 6
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Subject: | Re: Crowbar OV module placement |
The regulator is the solid-state supplied from InterAv as a kit to work with the
Motorola Alternator i'm using the schematic of the interAv system and hooking
up the OVM from the B&C system if I can hook to the field on the InterAv system
then all my troubles are over that's what I wanted to do
the mention of the 5 amp not kicking the regulator in just disregard ! that was
a whole Nother scenario!
do you still recommend me to change to a voltage limiter on the firewall as suggested
before? if not I'm done ,I have it accomplished! Thank you again!!
John
Sent from my iPhone
> On Jul 21, 2014, at 11:01 AM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
>
> At 07:25 AM 7/21/2014, you wrote:
>>
>> yes I'm using the B&C schematic with an external regulator ,(no changes) it
says to hook the ovm to regulator in & to the master switch .
>> I want to hook it to the field which has a five amp breaker .
>> I'm asking why I can't do that instead of the regulator in?
>
> The crowbar ov module functions by creating
> a high current (artificial fault) on the field
> voltage supply line for the purpose of
> forcing the field supply breaker open . . .
> thus depriving the alternator of field
> excitation an shutting it down.
>
> That 'fault' may be applied anywhere along
> the supply line between the breaker and
> the regulator's input terminal.
>
> What kind of regulator are you using?
>
> You mentioned something to the effect that
> a 5A breaker seemed inadequate to getting
> the alternator to come alive? You need
> to get the alternator working first using
> details from the B&C drawing . . . the
> breaker sizes cited are correct.
>
> After the alternator is working, then add
> the OV module at any point along the field
> excitation power path.
>
>
>
> Bob . . .
>
>
>
>
Message 7
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Subject: | Re: Are 'serial' contactors really needed? |
I understand !! I thank you very very very much you guys are lifesaver it's a please
dealing with you and your staff !!
Thank You
John
Sent from my iPhone
> On Jul 21, 2014, at 10:40 AM, "user9253" <fransew@gmail.com> wrote:
>
>
>
>> it says to hook the ovm to regulator in & to the master switch
>
> No it doesn't.
> B&C schematic link: http://www.bandc.biz/pdfs/OVM_wiringdiagram.pdf
> The B&C schematic shows the black wire of the O.V. module connected to ground.
They just happened to use the same ground that the master switch is connected
to. You can connect the black wire to any convenient ground.
> I think that B&C drew the schematic that way for two reasons: 1. It is easy to
draw. 2. It is easy to wire directly at the master switch because both ground
and the alternator field circuit are available there (if your master switch
is wired like B&C's switch is wired).
> As for the colored wire (orange?) of the O.V., B&C shows it connected to the
alternator-field half of the master switch. Electrically speaking, this is the
same as connecting to the voltage regulator input. In either case, power is
coming from the 5 amp breaker.
> Now if you want to connect the O.V. module directly to the 5 amp breaker, I see
no reason why that will not work. I hope others will correct me if wrong.
Just make sure that it is connected to the down stream side and not the always
hot side of the breaker.
> In summary, connect the O.V. black wire to ground. And connect the other wire
to some point between the 5 amp breaker and the input to the voltage regulator.
> Joe
>
> --------
> Joe Gores
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=427062#427062
>
>
>
>
>
>
>
>
>
>
Message 8
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Subject: | Transmitting with no antenna? |
I'm working on an audio panel/radio problem and I was told that pressing the PTT
(transmitting) without an antenna will fry the radio. [Embarassed]
Is this correct or is it an OWT?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=427077#427077
Message 9
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Subject: | Z13 fusible link, circuit breaker, same circuit? |
Something puzzles me . . .
Drawing Z-13/8 rev T dated 1/17/2014 shows both a 22AWG fusible link and a
5A circuit breaker between the main bus and terminal 5 of the Bat/Alt DC Po
wer switch. When the Bat/Alt DC Power switch is closed and the alternator i
s making power, the 5A circuit breaker will open if the crowbar over voltag
e protection module connected to terminal 4 of the Bat/Alt DC Power switch,
senses an over voltage condition and grounds the circuit. This functionali
ty I understand.
The wire between the fusible link and the circuit breaker is called out as
18AWG, thus the four size smaller 22AWG fusible link makes sense to me. Thr
ee questions:
1. What is the function of the 22AWG fusible link in this circuit?
2. Shouldn't the wire from the 5A circuit breaker to the Bat/Alt DC Pow
er switch and the wire from the Bat/Alt DC Power switch terminal 4 to the v
oltage regulator terminal A also be 18AWG?
3. Alternatively, assuming the 20AWG wire is sufficient to carry the lo
ad, shouldn't all wires in this circuit be 20AWG and the fusible link be 16
AWG, i.e. 4 sizes smaller?
Thanks in advance for unpuzzling me.
Message 10
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Subject: | Re: Transmitting with no antenna? |
It's not a good idea; transmitting into an open circuit can damage
that final power amplifier stage as the signal is reflected back into
it. But most radios built in the past 20-30 years will have built-in
foldback protection to detect this condition and dial the power back
to avoid damage.
Henry
On Mon, Jul 21, 2014 at 1:27 PM, donjohnston <don@velocity-xl.com> wrote:
>
> I'm working on an audio panel/radio problem and I was told that pressing the
PTT (transmitting) without an antenna will fry the radio. [Embarassed]
>
> Is this correct or is it an OWT?
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=427077#427077
>
>
Message 11
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Subject: | Re: Z13 fusible link, circuit breaker, same circuit? |
Just to clarify:
Question 3 : four sizes smaller than 20awg, is 24awg, not 16
John
Sent from my iPad
----x--O--x----
> On 21 Jul 2014, at 09:55 pm, "Bower, Bob" <Bob.Bower@hdrinc.com> wrote:
>
> Something puzzles me . . .
>
> Drawing Z-13/8 rev T dated 1/17/2014 shows both a 22AWG fusible link and a
5A circuit breaker between the main bus and terminal 5 of the Bat/Alt DC Po
wer switch. When the Bat/Alt DC Power switch is closed and the alternator is
making power, the 5A circuit breaker will open if the crowbar over voltage p
rotection module connected to terminal 4 of the Bat/Alt DC Power switch, sen
ses an over voltage condition and grounds the circuit. This functionality I u
nderstand.
>
> The wire between the fusible link and the circuit breaker is called out as
18AWG, thus the four size smaller 22AWG fusible link makes sense to me. Thr
ee questions:
>
> 1. What is the function of the 22AWG fusible link in this circuit?
> 2. Shouldn=99t the wire from the 5A circuit breaker to the Bat/A
lt DC Power switch and the wire from the Bat/Alt DC Power switch terminal 4 t
o the voltage regulator terminal A also be 18AWG?
> 3. Alternatively, assuming the 20AWG wire is sufficient to carry the l
oad, shouldn=99t all wires in this circuit be 20AWG and the fusible li
nk be 16AWG, i.e. 4 sizes smaller?
>
> Thanks in advance for unpuzzling me.
>
>
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=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
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=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>
Message 12
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Subject: | Re: Transmitting with no antenna? |
henry(at)pericynthion.org wrote:
> It's not a good idea; transmitting into an open circuit can damage
> that final power amplifier stage as the signal is reflected back into
> it. But most radios built in the past 20-30 years will have built-in
> foldback protection to detect this condition and dial the power back
> to avoid damage.
>
> Henry
>
> On Mon, Jul 21, 2014 at 1:27 PM, donjohnston wrote:
>
Thanks!
What should I do to prevent any potential problem? Would a 50 ohm terminating
resistor be a good idea? I'm not going to be able to connect the antennas for
a while and I'd like to not have to worry about any problems.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=427085#427085
Message 13
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Subject: | Re: Transmitting with no antenna? |
Is it an OWT (old wives tale): I don't know but where are those 'ouput watts' going,
if you don't have an aerial connected
John
Sent from my iPad
----x--O--x----
> On 21 Jul 2014, at 09:27 pm, "donjohnston" <don@velocity-xl.com> wrote:
>
>
> I'm working on an audio panel/radio problem and I was told that pressing the
PTT (transmitting) without an antenna will fry the radio. [Embarassed]
>
> Is this correct or is it an OWT?
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=427077#427077
>
>
>
>
>
>
>
>
>
>
Message 14
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Subject: | Z13 fusible link, circuit breaker, same circuit? |
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Message 15
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Subject: | Re: Transmitting with no antenna? |
It depends on the radio design. The problem is that the radio is meant
to have an antenna connected to it that is designed to operate on the
frequency the transmitter is transmitting at. When that doesn't happen
all the power that the transmitter is producing is "reflected" back into
the transmitter. That can fry things. Most well designed modern
transmitters have protection circuits that reduce the transmitter power
or disable the transmitter when it detects that condition. It's still a
bad idea to transmit with no antenna (or the wrong antenna) connected.
This goes for Comm radios, Transponders, Radio Altimeters, TCAS boxes...
Bill
On 7/21/14, 1:27 PM, donjohnston wrote:
>
> I'm working on an audio panel/radio problem and I was told that pressing the
PTT (transmitting) without an antenna will fry the radio. [Embarassed]
>
> Is this correct or is it an OWT?
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=427077#427077
>
>
Message 16
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Subject: | Re: Transmitting with no antenna? |
Most 50 Ohm terminating resistors are rated for a half watt or less.
Most Comm radios put out 5 watts or more. The terminating resistor won't
last long. 1) Keep the radio turned off when you're working on things.
2) Disconnect the PTT wire from the radio connector if that's feasible.
Termination resistors are made to keep a constant impedance connection
on something like a spare antenna diplexer port, not dissipate the power
from a transmitter. You can get 50 dummy loads that are designed to be
transmitted into all day long. They're a lot more expensive than a
terminator and much bulkier. Even a dummy load will only operate at it's
rated power for a limited time. Make sure you look at all the specs for
what you buy. Most of the time you're going to be transmitting without
you knowing it because a wiring short or sitting on the mic (or
something like that). You're likely to be transmitting for a long time
or until the stuck mic circuit in the transmitter shuts it down.
Bill
On 7/21/14, 2:50 PM, donjohnston wrote:
>
>
> henry(at)pericynthion.org wrote:
>> It's not a good idea; transmitting into an open circuit can damage
>> that final power amplifier stage as the signal is reflected back into
>> it. But most radios built in the past 20-30 years will have built-in
>> foldback protection to detect this condition and dial the power back
>> to avoid damage.
>>
>> Henry
>>
>> On Mon, Jul 21, 2014 at 1:27 PM, donjohnston wrote:
>>
>
>
> Thanks!
>
> What should I do to prevent any potential problem? Would a 50 ohm terminating
resistor be a good idea? I'm not going to be able to connect the antennas for
a while and I'd like to not have to worry about any problems.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=427085#427085
>
>
Message 17
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Subject: | Transmitting with no antenna? |
As per some other post in reply yes it can lead to damage to the output
stage of the connected radio. The high SWR presented to the
Output side by no Antenna or the wrong antenna causes significant heating to
the output transistors and can cause their internal junctions to fail.
You can go to your local Ham Radio shop and purchase a small 50 Ohm dummy
load for a few dollars to protect the connected radios or indeed test the
Radios without an antenna. You will need a VHF, 50 Ohm Dummy Load Capable of
handling 25 watts (less if you keep the transmissions short say 4-5
seconds).
Cheers
John MacCallum
VH-DUU
RV10 41016
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
donjohnston
Sent: Tuesday, 22 July 2014 6:28 AM
Subject: AeroElectric-List: Transmitting with no antenna?
--> <don@velocity-xl.com>
I'm working on an audio panel/radio problem and I was told that pressing the
PTT (transmitting) without an antenna will fry the radio. [Embarassed]
Is this correct or is it an OWT?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=427077#427077
Message 18
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Subject: | Re: Transmitting with no antenna? |
Alternatively, you could build this dummy load: http://bit.ly/1wSMtI1
...using 20 of these (buy 25 for the price break): http://bit.ly/1lnVgfM
Note: Do *not* substitute wire-wound resistors!
Eric
> On Jul 21, 2014, at 5:22 PM, John MacCallum <john.maccallum@bigpond.com> wrote:
>
> You can go to your local Ham Radio shop and purchase a small 50 Ohm dummy load
for a few dollars to protect the connected radios or indeed test the Radios
without an antenna. You will need a VHF, 50 Ohm Dummy Load Capable of handling
25 watts (less if you keep the transmissions short say 4-5 seconds).
>
> Cheers
> John MacCallum
> VH-DUU
> RV10 41016
>
>
> I'm working on an audio panel/radio problem and I was told that pressing the
> PTT (transmitting) without an antenna will fry the radio. [Embarassed]
>
> Is this correct or is it an OWT?
Message 19
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Subject: | Re: Crowbar OV module placement |
At 12:27 PM 7/21/2014, you wrote:
The regulator is the solid-state supplied from InterAv as a kit to
work with the Motorola Alternator i'm using the schematic of the
interAv system and hooking up the OVM from the B&C system if I can
hook to the field on the InterAv system then all my troubles are over
that's what I wanted to do
Very good.
the mention of the 5 amp not kicking the regulator in just
disregard ! that was a whole Nother scenario!
do you still recommend me to change to a voltage limiter on the
firewall as suggested before? if not I'm done ,I have it
accomplished! Thank you again!!
If you have a 60A breaker already installed and
wired, leave it.
Pleased to have a clearer picture of what you were
wrestling with.
Bob . . .
Message 20
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Subject: | Re: Transmitting with no antenna? |
At 03:27 PM 7/21/2014, you wrote:
I'm working on an audio panel/radio problem and I was told that
pressing the PTT (transmitting) without an antenna will fry the
radio. [Embarassed]
Is this correct or is it an OWT?
I wouldn't make a habit of it . . . there's no
good reason to do it. If you need to listen to
your transmitted signal without radiating it more
than a few dozen yards, build yourself a dummy
load to put on the transmitter's coax connector.
http://tinyurl.com/cchp3pf
This load is good for 2W continuous and will handle
10W transmitters for the few seconds necessary to make
a vocal test transmission to deduce audio quality.
If you need a bigger load, it too can be fabricated
from R-S parts.
But the caveat about keying a transmitter into
an open antenna jack is a carry-over from the state
of solid state radios of the 60-70's. It didn't
take the industry long to figure out ways to build
protections into their products . . . so keying
an unloaded transmitter no longer represents
a serious hazard.
Bob . . .
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