Today's Message Index:
----------------------
1. 12:28 AM - current limiting an alternator (Bob Verwey)
2. 06:34 AM - Re: current limiting an alternator (Robert L. Nuckolls, III)
3. 08:37 AM - Re: current limiting an alternator (Bob Verwey)
4. 09:57 AM - Re: current limiting an alternator (Robert L. Nuckolls, III)
5. 12:59 PM - TM-902C Digital LCD K Type Thermometer meter (marvin haught)
6. 01:20 PM - Re: TM-902C Digital LCD K Type Thermometer meter (Robert L. Nuckolls, III)
7. 01:28 PM - Digital multimeter recommendation (Larry Winger)
8. 01:42 PM - Re: Digital multimeter recommendation (Ed Gilroy)
9. 02:12 PM - Re: Digital multimeter recommendation (Henry Hallam)
10. 02:57 PM - Re: Digital multimeter recommendation (RGent1224@aol.com)
11. 03:13 PM - Re: Digital multimeter recommendation (Ed Gilroy)
12. 03:34 PM - Re: TM-902C Digital LCD K Type Thermometer meter (marvin haught)
13. 06:59 PM - KT-76A transponder blowing fuse (Henry Hallam)
14. 08:45 PM - Initial amp spike on PTT (Bill Bradburry)
15. 09:17 PM - Re: Digital multimeter recommendation (RGent1224@aol.com)
16. 10:00 PM - Re: Initial amp spike on PTT (Robert L. Nuckolls, III)
Message 1
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Subject: | current limiting an alternator |
Listers,
Is it economically and relatively simple to limit charging current from an
alternator in a 12v system? The automotive alternators have relatively high
initial output and looking at my small electrical loads, I don't see the
need for a massive battery...or have I got it all wrong?? <grin>
Bob Verwey
IO470 Bonanza A35 ZU-DLW
V6 Chevy Safari ZU-AJF
Message 2
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Subject: | Re: current limiting an alternator |
At 02:26 AM 12/4/2012, you wrote:
Listers,
Is it economically and relatively simple to limit charging current
from an alternator in a 12v system? The automotive alternators have
relatively high initial output and looking at my small electrical
loads, I don't see the need for a massive battery...or have I got it
all wrong?? <grin>
While an alternator has the CAPABILITY of delivering
energy at relatively high rates, it can do so only
if the LOAD is willing to accept it based on
VOLTAGE DIFFERENTIALS and total loop resistance.
When you hook an energy consumer across the bus,
the current it requires is relatively constant and
only slightly dependent on bus voltage. But an
energy storage device (battery) may present a
load to the bus that is initially several volts
lower than the bus voltage set point.
Now, you have the POTENTIAL for some serious
currents to flow but even that's limited by the
internal resistance of the battery. Intuitively
one sees a potential hazard to, let us say, a 2 a.h.
SLVA battery being totally discharged and then connected
across a bus capable of delivering 40+ amps
at normal bus voltages. Indeed, the itty-bitty
battery's acceptance will 'spike' on initial
connection but probably no where near 40 amps
and it will fall rapidly. The risk to the battery
is not so much from 'hammering energy into a
chemical conversion'; the greatest potential
for damage is from heating of the internals
as a result of I(squared) x R watts being
dissipated within the small mass. This is
made worse by the fact that the dissipation
is not necessarily spread evenly throughout
the battery's chemistry.
The battery will not necessarily drown
upon experiencing its first 'drink from the
firehose' but a series of such events will
chip away at battery performance and severely
shorten its potential service life.
It would help to know more about your design
goals. What size battery are you wanting to
use? Is this battery going to be your only
source of energy during failure of the boss-
hog alternator? Have you established endurance
goals for alternator-out operations? Aside
from engine cranking, ENDURANCE goals are the
big driver of battery size. Can you give
us more numbers as to size of battery you
want to use and how this battery fits into
your consideration for a comfortable Plan-B
termination of flight after an alternator
failure?
Bob . . .
Message 3
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Subject: | Re: current limiting an alternator |
Hi Bob,
As usual, you have put much more thought into your answer than I did into
my question!
My craft is powered by a Chevy V6 with a single aftermarket ignition coil,
specifically designed for "high vibration environments". My endurance goals
for alternator-out operations would be 30 minutes, as I will be strictly
day VFR, and with a cruise speed of 100 knots I will have some options.
Electrical loads are the usual ignition system, 2 comms, GPS, landing
light, but really the very basics required. No fuel pump, high wing with
carb. I had the H35 battery in mind, same as in the Bonanza.
I am not considering an endurance bus.
Bob Verwey
IO470 Bonanza A35 ZU-DLW
V6 Chevy Safari ZU-AJF
On 4 December 2012 16:33, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> nuckolls.bob@aeroelectric.com**>
>
> At 02:26 AM 12/4/2012, you wrote:
> Listers,
>
> Is it economically and relatively simple to limit charging current from an
> alternator in a 12v system? The automotive alternators have relatively high
> initial output and looking at my small electrical loads, I don't see the
> need for a massive battery...or have I got it all wrong?? <grin>
>
> While an alternator has the CAPABILITY of delivering
> energy at relatively high rates, it can do so only
> if the LOAD is willing to accept it based on
> VOLTAGE DIFFERENTIALS and total loop resistance.
>
> When you hook an energy consumer across the bus,
> the current it requires is relatively constant and
> only slightly dependent on bus voltage. But an
> energy storage device (battery) may present a
> load to the bus that is initially several volts
> lower than the bus voltage set point.
>
> Now, you have the POTENTIAL for some serious
> currents to flow but even that's limited by the
> internal resistance of the battery. Intuitively
> one sees a potential hazard to, let us say, a 2 a.h.
> SLVA battery being totally discharged and then connected
> across a bus capable of delivering 40+ amps
> at normal bus voltages. Indeed, the itty-bitty
> battery's acceptance will 'spike' on initial
> connection but probably no where near 40 amps
> and it will fall rapidly. The risk to the battery
> is not so much from 'hammering energy into a
> chemical conversion'; the greatest potential
> for damage is from heating of the internals
> as a result of I(squared) x R watts being
> dissipated within the small mass. This is
> made worse by the fact that the dissipation
> is not necessarily spread evenly throughout
> the battery's chemistry.
>
> The battery will not necessarily drown
> upon experiencing its first 'drink from the
> firehose' but a series of such events will
> chip away at battery performance and severely
> shorten its potential service life.
>
> It would help to know more about your design
> goals. What size battery are you wanting to
> use? Is this battery going to be your only
> source of energy during failure of the boss-
> hog alternator? Have you established endurance
> goals for alternator-out operations? Aside
> from engine cranking, ENDURANCE goals are the
> big driver of battery size. Can you give
> us more numbers as to size of battery you
> want to use and how this battery fits into
> your consideration for a comfortable Plan-B
> termination of flight after an alternator
> failure?
>
>
> Bob . . .
>
>
Message 4
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Subject: | Re: current limiting an alternator |
At 10:35 AM 12/4/2012, you wrote:
Hi Bob,
As usual, you have put much more thought into your answer than I did
into my question!
My craft is powered by a Chevy V6 with a single aftermarket ignition
coil, specifically designed for "high vibration environments". My
endurance goals for alternator-out operations would be 30 minutes, as
I will be strictly day VFR, and with a cruise speed of 100 knots I
will have some options.
Electrical loads are the usual ignition system, 2 comms, GPS, landing
light, but really the very basics required. No fuel pump, high wing
with carb. I had the H35 battery in mind, same as in the Bonanza.
I am not considering an endurance bus.
Okay. According to this posting
http://tinyurl.com/cryc6w3
The battery on an H35 is a 12 volt, rated
at 29 a.h. for a one-hour rate. At 30
pounds this is not a wimpy device. On the
certified airplane, it's paired with at least
a 60A alternator. There might have been an
larger alternator offered as an option.
Many of our brothers are flying 17 a.h. batteries
with alternators of 40 amps or more.
Can you articulate a foundation for your
concerns? Even if you don't have an E-bus,
consider a battery bus that supplies power
for the ignition system. You should be able
to fly this airplane with the battery master
and alternator switches OFF.
Bob . . .
Message 5
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Subject: | TM-902C Digital LCD K Type Thermometer meter |
I saw the thread a while back on this temp meter, and guess I missed
most of it. I just ordered 10 of the units for resale (I am a
distributor for Stewart Systems Aircraft Finishes) and decided the meter
was a cheap alternative for the $25 multimeter that I've been selling
for calibrating irons used to shrink fabric. I thought I saw a message
where someone calibrated the meter using boiling water? Is my memory
correct? Can someone either send that message to me again or steer me
to it?
M. Haught
Message 6
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Subject: | Re: TM-902C Digital LCD K Type Thermometer meter |
At 02:57 PM 12/4/2012, you wrote:
><handainc@madisoncounty.net>
>
>I saw the thread a while back on this temp meter, and guess I missed
>most of it. I just ordered 10 of the units for resale (I am a
>distributor for Stewart Systems Aircraft Finishes) and decided the
>meter was a cheap alternative for the $25 multimeter that I've been
>selling for calibrating irons used to shrink fabric. I thought I
>saw a message where someone calibrated the meter using boiling
>water? Is my memory correct? Can someone either send that message
>to me again or steer me to it?
From my archives:
------------------------------------
The procedure I used was to immerse the probe in ice water and adjust
the display to 0 deg C. Next was to immerse the probe in boiling
water and adjust the display to 100 deg C. Repeat until no further
adjustment is needed.
Raymond Julian
On 10/24/2012 05:07 PM, rayj wrote:
>Greetings,
>
>I calibrated the 3 TM-902C hand held instruments. I was able to
>adjust them to read the same at both 0 and 100 deg C. It seemed to
>take 2-3 cycles from cold to hot and back to get them to settle
>down, but once they did they all were very consistent at both ends
>of the range tested.
>
>As I reviewed Bob's posting I noticed that the boards in mine are a
>different layout than the one pictured. I'll include a picture of
>mine if I can get to upload.
>
>On mine one adjustment point is to the left of the yellow connector
>(6:30 position) near the edge of the board. The second is located
>at the 3:00 position.
>
>The 6:30 position adjusts the readout at 0 deg C. The 3:00 position
>adjusts the readout at 100 deg C. As I mentioned earlier it seemed
>to take 2-3 cycles before it becomes stable.
>
>On both adjustments turning clockwise lowered the value
>displayed. CCW raised it.
>
>--
>Raymond Julian
>Kettle River, MN
------------------------------------
Bob . . .
Message 7
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Subject: | Digital multimeter recommendation |
I've just completed wiring my Zenith CH 650 and believe it is time to
upgrade from the Harbor Freight multimeter I've been using. I'll like to
have one that can provide audio alerts when doing continuity testing, along
with all the normal functionality you would expect when troubleshooting an
aircraft electrical system. It would be great if I could find a really
solid, full-featured unit for under $75. Any suggestions?
Larry Winger
Tustin, CA
Zenith CH 650/Corvair
Doing final punch list before my hangar move
Message 8
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Subject: | Re: Digital multimeter recommendation |
Buy a working Fluke off of Craigslist...
On Tue, Dec 4, 2012 at 4:27 PM, Larry Winger <larrywinger@gmail.com> wrote:
> I've just completed wiring my Zenith CH 650 and believe it is time to
> upgrade from the Harbor Freight multimeter I've been using. I'll like to
> have one that can provide audio alerts when doing continuity testing, along
> with all the normal functionality you would expect when troubleshooting an
> aircraft electrical system. It would be great if I could find a really
> solid, full-featured unit for under $75. Any suggestions?
>
> Larry Winger
> Tustin, CA
> Zenith CH 650/Corvair
> Doing final punch list before my hangar move
>
> *
>
> *
>
>
Message 9
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Subject: | Re: Digital multimeter recommendation |
Agreed (or eBay). Used Fluke 77 meters are around your price range
and they're great. Especially if there's any RF interference around,
it's really worth having a quality meter.
Henry
On Tue, Dec 4, 2012 at 1:40 PM, Ed Gilroy <egilroy@gmail.com> wrote:
> Buy a working Fluke off of Craigslist...
>
>
> On Tue, Dec 4, 2012 at 4:27 PM, Larry Winger <larrywinger@gmail.com> wrote:
>>
>> I've just completed wiring my Zenith CH 650 and believe it is time to
>> upgrade from the Harbor Freight multimeter I've been using. I'll like to
>> have one that can provide audio alerts when doing continuity testing, along
>> with all the normal functionality you would expect when troubleshooting an
>> aircraft electrical system. It would be great if I could find a really
>> solid, full-featured unit for under $75. Any suggestions?
>>
>> Larry Winger
>> Tustin, CA
>> Zenith CH 650/Corvair
>> Doing final punch list before my hangar move
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> _blank">http://www.matronics.com/contribution
>> ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
>> tp://forums.matronics.com
>>
>
>
Message 10
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Subject: | Re: Digital multimeter recommendation |
Question I have a Fluke 8020 B multimeter and I think it needs to be
calibrated. The voltages appear to be off a bit. How much would it cost and
anyplace where it could be done.
Thanks,
Dick
In a message dated 12/4/2012 4:13:33 P.M. Central Standard Time,
henry@pericynthion.org writes:
--> AeroElectric-List message posted by: Henry Hallam
<henry@pericynthion.org>
Agreed (or eBay). Used Fluke 77 meters are around your price range
and they're great. Especially if there's any RF interference around,
it's really worth having a quality meter.
Henry
On Tue, Dec 4, 2012 at 1:40 PM, Ed Gilroy <egilroy@gmail.com> wrote:
> Buy a working Fluke off of Craigslist...
>
>
> On Tue, Dec 4, 2012 at 4:27 PM, Larry Winger <larrywinger@gmail.com>
wrote:
>>
>> I've just completed wiring my Zenith CH 650 and believe it is time to
>> upgrade from the Harbor Freight multimeter I've been using. I'll like
to
>> have one that can provide audio alerts when doing continuity testing,
along
>> with all the normal functionality you would expect when troubleshooting
an
>> aircraft electrical system. It would be great if I could find a really
>> solid, full-featured unit for under $75. Any suggestions?
>>
>> Larry Winger
>> Tustin, CA
>> Zenith CH 650/Corvair
>> Doing final punch list before my hangar move
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> _blank">http://www.matronics.com/contribution
>> ist"
target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
>> tp://forums.matronics.com
>>
>
>
Message 11
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Subject: | Re: Digital multimeter recommendation |
http://www.fluke.com/fluke/usen/service/calibration/default.htm
On Tue, Dec 4, 2012 at 5:55 PM, <RGent1224@aol.com> wrote:
> **
> Question I have a Fluke 8020 B multimeter and I think it needs to be
> calibrated. The voltages appear to be off a bit. How much would it cost and
> anyplace where it could be done.
> Thanks,
> Dick
>
> In a message dated 12/4/2012 4:13:33 P.M. Central Standard Time,
> henry@pericynthion.org writes:
>
> henry@pericynthion.org>
>
> Agreed (or eBay). Used Fluke 77 meters are around your price range
> and they're great. Especially if there's any RF interference around,
> it's really worth having a quality meter.
>
> Henry
>
> On Tue, Dec 4, 2012 at 1:40 PM, Ed Gilroy <egilroy@gmail.com> wrote:
> > Buy a working Fluke off of Craigslist...
> >
> >
> > On Tue, Dec 4, 2012 at 4:27 PM, Larry Winger <larrywinger@gmail.com>
> wrote:
> >>
> >> I've just completed wiring my Zenith CH 650 and believe it is time to
> >> upgrade from the Harbor Freight multimeter I've been using. I'll like
> to
> >> have one that can provide audio alerts when doing continuity testing,
> along
> >> with all the normal functionality you would expect when troubleshooting
> an
> >> aircraft electrical system. It would be great if I could find a really
> >> solid, full-featured unit for under $75. Any suggestions?
> >>
> >> Larry Winger
> >> Tustin, CA
> >> Zenith CH 650/Corvair
> >> Doing final punch list before my hangar move
> >>
> >> _blank">www.aeroelectric.com
> >> .com" target="_blank">www.buildersbooks.com
> >> ="_blank">www.homebuilthelp.com
> >> _blank">http://www.matronics.com/contribution
> >> ist" target="_blank">
> http://www.matronics.com/Navigator?AeroElectric-List
> >> tp://forums.matronics.com
> >>
> >
> >
> >
> >
> bsp; (And Get Some AWESOME FREE o find ifts bsp; lder's LP you
> for ; -Matt Dralle, List = Use ilities ay
> - MATRONICS WEB FORUMS
>
>
> *
>
> *
>
>
Message 12
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Subject: | Re: TM-902C Digital LCD K Type Thermometer meter |
Thanks Bob - Just what I needed.
M. Haught
On 12/4/2012 3:19 PM, Robert L. Nuckolls, III wrote:
> At 02:57 PM 12/4/2012, you wrote:
>> <handainc@madisoncounty.net>
>>
>> I saw the thread a while back on this temp meter, and guess I missed
>> most of it. I just ordered 10 of the units for resale (I am a
>> distributor for Stewart Systems Aircraft Finishes) and decided the
>> meter was a cheap alternative for the $25 multimeter that I've been
>> selling for calibrating irons used to shrink fabric. I thought I saw
>> a message where someone calibrated the meter using boiling water? Is
>> my memory correct? Can someone either send that message to me again
>> or steer me to it?
>
>
> From my archives:
> ------------------------------------
>
> The procedure I used was to immerse the probe in ice water and adjust
> the display to 0 deg C. Next was to immerse the probe in boiling
> water and adjust the display to 100 deg C. Repeat until no further
> adjustment is needed.
>
> Raymond Julian
>
> On 10/24/2012 05:07 PM, rayj wrote:
>> Greetings,
>>
>> I calibrated the 3 TM-902C hand held instruments. I was able to
>> adjust them to read the same at both 0 and 100 deg C. It seemed to
>> take 2-3 cycles from cold to hot and back to get them to settle down,
>> but once they did they all were very consistent at both ends of the
>> range tested.
>>
>> As I reviewed Bob's posting I noticed that the boards in mine are a
>> different layout than the one pictured. I'll include a picture of
>> mine if I can get to upload.
>>
>> On mine one adjustment point is to the left of the yellow connector
>> (6:30 position) near the edge of the board. The second is located at
>> the 3:00 position.
>>
>> The 6:30 position adjusts the readout at 0 deg C. The 3:00 position
>> adjusts the readout at 100 deg C. As I mentioned earlier it seemed
>> to take 2-3 cycles before it becomes stable.
>>
>> On both adjustments turning clockwise lowered the value displayed.
>> CCW raised it.
>>
>> --
>> Raymond Julian
>> Kettle River, MN
>
> ------------------------------------
>
> Bob . . .
>
> *
>
>
> *
Message 13
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Subject: | KT-76A transponder blowing fuse |
Dear Aeroelectrons,
My KT-76A (ser # 33921) has been occasionally tripping its 2A breaker
for a while. I let it run on the bench with a power logger and a 3A
supply and now after 30 minutes it has blown its internal 2A fuse. No
obvious burned components or leaky capacitors... any ideas for failure
modes? Does anyone have a schematic?
Thanks,
Henry
Message 14
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Subject: | Initial amp spike on PTT |
My hangar mate and I checked the current in the wire pulled to ground by the
PTT and found an initial spike of almost 2 amps. This seems excessive to
me. After the initial spike it dropped down to a low number that I don't
currently remember, but close to what I would think is acceptable in the
millamp range.
The radio is a Garmin GNS 430W.
Any comments on this?
Bill B
Message 15
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Subject: | Re: Digital multimeter recommendation |
Thanks
In a message dated 12/4/2012 5:14:55 P.M. Central Standard Time,
egilroy@gmail.com writes:
_http://www.fluke.com/fluke/usen/service/calibration/default.htm_
(http://www.fluke.com/fluke/usen/service/calibration/default.htm)
On Tue, Dec 4, 2012 at 5:55 PM, <_RGent1224@aol.com_
(mailto:RGent1224@aol.com) > wrote:
Question I have a Fluke 8020 B multimeter and I think it needs to be
calibrated. The voltages appear to be off a bit. How much would it cost and
anyplace where it could be done.
Thanks,
Dick
In a message dated 12/4/2012 4:13:33 P.M. Central Standard Time,
_henry@pericynthion.org_ (mailto:henry@pericynthion.org) writes:
--> AeroElectric-List message posted by: Henry Hallam
<_henry@pericynthion.org_ (mailto:henry@pericynthion.org) >
Agreed (or eBay). Used Fluke 77 meters are around your price range
and they're great. Especially if there's any RF interference around,
it's really worth having a quality meter.
Henry
On Tue, Dec 4, 2012 at 1:40 PM, Ed Gilroy <_egilroy@gmail.com_
(mailto:egilroy@gmail.com) > wrote:
> Buy a working Fluke off of Craigslist...
>
>
> On Tue, Dec 4, 2012 at 4:27 PM, Larry Winger <_larrywinger@gmail.com_
(mailto:larrywinger@gmail.com) > wrote:
>>
>> I've just completed wiring my Zenith CH 650 and believe it is time to
>> upgrade from the Harbor Freight multimeter I've been using. I'll like
to
>> have one that can provide audio alerts when doing continuity testing,
along
>> with all the normal functionality you would expect when troubleshooting
an
>> aircraft electrical system. It would be great if I could find a really
>> solid, full-featured unit for under $75. Any suggestions?
>>
>> Larry Winger
>> Tustin, CA
>> Zenith CH 650/Corvair
>> Doing final punch list before my hangar move
>>
>> _blank">_www.aeroelectric.com_ (http://www.aeroelectric.com/)
>> .com" target="_blank">_www.buildersbooks.com_
(http://www.buildersbooks.com/)
>> ="_blank">_www.homebuilthelp.com_ (http://www.homebuilthelp.com/)
>> _blank">_http://www.matronics.com/contribution_
(http://www.matronics.com/contribution)
>> ist"
target="_blank">_http://www.matronics.com/Navigator?AeroElectric-List_ (http://www.matronics.com/Navigator?AeroElectric-List)
>> tp://_forums.matronics.com_ (http://forums.matronics.com/)
>>
>
>
bsp; (And Get Some AWESOME FREE o find ifts bsp; lder's LP you for ;
-Matt Dralle, List = Use ilities ay - MATRONICS WEB FORUMS
_blank">www.aeroelectric.com
.com" target="_blank">www.buildersbooks.com ="_blank">www.homebuilthelp.com
_blank">http://www.matronics.com/contribution ist"
target="_blank">http://www.matronics.com/Navigator?AeroElectric-List tp://forums.matronics.com
(http://www.aeroelectric.com/)
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Subject: | Re: Initial amp spike on PTT |
At 10:43 PM 12/4/2012, you wrote:
><bbradburry@bellsouth.net>
>
>My hangar mate and I checked the current in the wire pulled to ground by the
>PTT and found an initial spike of almost 2 amps. This seems excessive to
>me. After the initial spike it dropped down to a low number that I don't
>currently remember, but close to what I would think is acceptable in the
>millamp range.
What is the duration of the spike? The PTT
line coming out of the radio may have some
form of RFI ingress protection that includes
capacitance to ground. Any capacitor rapidly
discharged through the PTT circuit will produce
some large 'inrush' currents but they're typically
very short duration hence low energy.
Bob . . .
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