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Lynn Coffelt
 
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Default what size wire to use for 30amp 12v circuit ?

The Ancor calculator Matt mentioned is about right. Things to keep in mind
are that a 25 foot length of wire is only good for 12.5 feet of
distance..........out and back, right?

And the type insulation is worth considering, particularly if it's
going to be near any heat, oil, sunlight, etc, etc.

Remember also that under emergency conditions (no alternator turning)
there isn't going to be that comfortable 14.7 volts to fall back on, but
something like 12.3 or 12.4 from a good, recently charged battery. Lots of
high class SSB radios will start jumping frequency or channels with 11 volts
at the radio, and the tuner will also be trying to retune everytime you
holler "Heeeelp" in the mic.

Welding cable is worth considering. Fine, cable laid wire with good
tough neoprene jacketing. Terminals deserve good swedged tools, and wicking
a little solder in after the swedging is super around salt water and
batteries.

Old Chief Lynn


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posted to rec.boats.electronics
Bruce in Alaska
 
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Default what size wire to use for 30amp 12v circuit ?

In article ,
"Lynn Coffelt" wrote:

The Ancor calculator Matt mentioned is about right. Things to keep in mind
are that a 25 foot length of wire is only good for 12.5 feet of
distance..........out and back, right?

And the type insulation is worth considering, particularly if it's
going to be near any heat, oil, sunlight, etc, etc.

Remember also that under emergency conditions (no alternator turning)
there isn't going to be that comfortable 14.7 volts to fall back on, but
something like 12.3 or 12.4 from a good, recently charged battery. Lots of
high class SSB radios will start jumping frequency or channels with 11 volts
at the radio, and the tuner will also be trying to retune everytime you
holler "Heeeelp" in the mic.

Welding cable is worth considering. Fine, cable laid wire with good
tough neoprene jacketing. Terminals deserve good swedged tools, and wicking
a little solder in after the swedging is super around salt water and
batteries.

Old Chief Lynn



I agree with "Old Chief Lynn" here, if the appliance we're discussing
here is an MF/HF SSB Radio. The thing that needs to be understood
is that Battery Voltage at the terminals is NOT Voltage at the back
of the Radio, or at the PowerAmp DC Terminals, especially at the 20
to 25 Amp draw of a 100 to 150 watt Peak Envelope Power Radio.
It is commonly understood that for each volt dropped from 13.6 VDC
at the radios PowerAmp DC Terminals, you lose 50% of your PEP Power.
So if your at 13.6 Vdc you get your 150 PEP, and at 12.6 VDC you
get 75 PEP, and at 11.6 Vdc you get 35 PEP and below 11.0 VDC
the internal Voltage Regulators drop out of regulation and the
radio goes OFF.
So any voltage drop associated with the wiring between the battery and
the radio at the the Demand Input Current of the radio, effects the
available output power. How many times have I seen a radio that receives
perfectly, but dies whenever you press the PTT and modulate the Mic.
LOTS. This is one of the reasons that the Powersupplys for FVSA
(Fishing Vessel Safety ACT) and SOLAS requires that any batteries
used for powering these MF/HF SSB Radios be on or above the same deck
as the Radio, and Battery Condition be certified each year by a
Discharge Test, in the case of SOLAS Required Vessels. When FVSA
was out for Public Comment, there was a bit of a uproar about this
requirment, as no one had that type of power system aboard, but
it was made LAW anyway, and most of the fleet installed the required
battery under the wheelhouse floor, right behind the wheelhouse
on that deck, or on top of the wheelhouse. These locations will
tend to keep the wire runs short, and any installer woirth his Salt,
should and would DOUBLE the wiresize on the MF/HF SSB Radio that
any table stated would be good enough.
Most of the vessels I Inspected had AC PowerSupplies, or DC/DC Converters
running from Ships Power of 120Vac or 32Vdc and Power leads of a foot or
two, before the FVSA, and we just added an 8D battery between the two.

Bruce in alaska
--
add a 2 before @
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posted to rec.boats.electronics
Eric Fairbank
 
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Default what size wire to use for 30amp 12v circuit ?

Where did you hear that myth??? Iv'e been a marine electronics tech for 30
years and have never heard that one. I know what you stated is total bs but
just for drill I did a little test before leaving work today. Hooked up a
variable power supply to my Icom 735 with a Bird 4381 power analyst in line
(which reads PEP directly). I also verified the wattmeter readings using an
o-scope. The power didn't start to drop til the voltage dropped below 10.5v
and I was able to receive just fine all the way down to 9.5v. Below that the
rig started to die.

Eric

"Bruce in Alaska" wrote in message
...
It is commonly understood that for each volt dropped from 13.6 VDC
at the radios PowerAmp DC Terminals, you lose 50% of your PEP Power.
So if your at 13.6 Vdc you get your 150 PEP, and at 12.6 VDC you
get 75 PEP, and at 11.6 Vdc you get 35 PEP and below 11.0 VDC
the internal Voltage Regulators drop out of regulation and the
radio goes OFF.



  #5   Report Post  
posted to rec.boats.electronics
Bruce in Alaska
 
Posts: n/a
Default what size wire to use for 30amp 12v circuit ?

In article ,
"Eric Fairbank" wrote:

Where did you hear that myth??? Iv'e been a marine electronics tech for 30
years and have never heard that one. I know what you stated is total bs but
just for drill I did a little test before leaving work today. Hooked up a
variable power supply to my Icom 735 with a Bird 4381 power analyst in line
(which reads PEP directly). I also verified the wattmeter readings using an
o-scope. The power didn't start to drop til the voltage dropped below 10.5v
and I was able to receive just fine all the way down to 9.5v. Below that the
rig started to die.

Eric

"Bruce in Alaska" wrote in message
...
It is commonly understood that for each volt dropped from 13.6 VDC
at the radios PowerAmp DC Terminals, you lose 50% of your PEP Power.
So if your at 13.6 Vdc you get your 150 PEP, and at 12.6 VDC you
get 75 PEP, and at 11.6 Vdc you get 35 PEP and below 11.0 VDC
the internal Voltage Regulators drop out of regulation and the
radio goes OFF.




It is not a Myth, is is a Fact, and as others have stated, your
experiment doesn't prove, or disprove the fact. Also, as Larry
stated the 21st Century Icom Rigs have a lot more headroom in the
SolidState Amps than just about any other Marine MF/HF Radio,
just to deal with this cause. Just try your experiment with ANY
SGC designed and built radio.

Bruce in alaska I am Old School, and an Old Fart, and I do remember
back in the Old Days, before Autotuners, allowed
anyone to think they were World Class Radiomen...
--
add a 2 before @


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posted to rec.boats.electronics
Meindert Sprang
 
Posts: n/a
Default what size wire to use for 30amp 12v circuit ?

"Bruce in Alaska" wrote in message
...
It is not a Myth, is is a Fact, and as others have stated, your
experiment doesn't prove, or disprove the fact. Also, as Larry
stated the 21st Century Icom Rigs have a lot more headroom in the
SolidState Amps than just about any other Marine MF/HF Radio,
just to deal with this cause.


But.... it is also a fact that any modern rig that is also allowed on
commercial vessels (IEC/EN60945) will never show this behavior, otherwise
they wouldn't be able to pass the the tests to comply with that standard.

Meindert


  #7   Report Post  
posted to rec.boats.electronics
Lynn Coffelt
 
Posts: n/a
Default what size wire to use for 30amp 12v circuit ?

"Eric Fairbank" wrote:

Where did you hear that myth??? Iv'e been a marine electronics tech

for 30
years and have never heard that one. I know what you stated is total bs

but
just for drill I did a little test before leaving work today. Hooked up

a
variable power supply to my Icom 735 with a Bird 4381 power analyst in

line
(which reads PEP directly). I also verified the wattmeter readings using

an
o-scope. The power didn't start to drop til the voltage dropped below

10.5v
and I was able to receive just fine all the way down to 9.5v. Below that

the
rig started to die.

Eric

"Bruce in Alaska" wrote in message
...
It is commonly understood that for each volt dropped from 13.6 VDC
at the radios PowerAmp DC Terminals, you lose 50% of your PEP Power.
So if your at 13.6 Vdc you get your 150 PEP, and at 12.6 VDC you
get 75 PEP, and at 11.6 Vdc you get 35 PEP and below 11.0 VDC
the internal Voltage Regulators drop out of regulation and the
radio goes OFF.




It is not a Myth, is is a Fact, and as others have stated, your
experiment doesn't prove, or disprove the fact. Also, as Larry
stated the 21st Century Icom Rigs have a lot more headroom in the
SolidState Amps than just about any other Marine MF/HF Radio,
just to deal with this cause. Just try your experiment with ANY
SGC designed and built radio.

Bruce in alaska I am Old School, and an Old Fart, and I do remember
back in the Old Days, before Autotuners, allowed
anyone to think they were World Class Radiomen...
--

Oh, my gosh, it's just killing me to sit here without jumping in! Then
when I heard SGC mentioned, I knew that someone besides me had experienced
"Bruce's Law". I am compelled to defend his position and scientific
observations without reservation.

How much midnight oil I've spent working on the DC supply system on
"commercial" vessels, trying to reduce the voltage drop. Until the "code"
made batterys in the pilot house almost mandatory, can't you imagine running
an SGC711 from engine room batterys? Here's a typical example (it is a
genuine "commercial", by the way) of a vessel still using this one time
popular rig:

http://www.alaskaboat.com/sn033.htm

Those SGC711's were hard to coax to even 75 watts PEP with any wire
less than #4 if you were more than two feet away from the battery! (OK,
stretching a little here) And the built-in wire antenna tuner was a charmer,
hey? But as the URL and dozens more can show, that not everyone has yet to
install an Icom M802.

Some earlier SEA's and Icom's with first generation digital VCO tuning
were cool, too. A sneeze or laugh in the mic was as apt to change channels
as anything if the antenna was fed directly from the radio, and some joker
installed #10 wire for DC power!

Early automatic antenna tuners were (are) cool, too. A little pitching
and rolling in the North Pacific and they would lock up and refuse to even
try to tune anymore. Then the transmitter's fabulous SWR power foldback
circuit hit the fan and 5 to 10 watts could be used to heat up the tuner's
coils and capacitors. (condensers, actually)

Lots of this early stuff is still out there. By the thousands. Modern
marine SSB radios certainly have improved their ability to survive poor
installations, but is that any reason to go as cheap as possible with DC
wiring and antenna installations? (RF ground on "Tupperware" boats is
probably just as important, but I digress)

Old Chief Lynn

(besides, tubes help heat the pilothouse and ease aching joints)


  #8   Report Post  
posted to rec.boats.electronics
Matt Colie
 
Posts: n/a
Default what size wire to use for 30amp 12v circuit ?



Lynn Coffelt wrote:
"Eric Fairbank" wrote:
Where did you hear that myth??? Iv'e been a marine electronics tech for 30
years and have never heard that one. I know what you stated is total bs but
just for drill I did a little test before leaving work today. Hooked up a
variable power supply to my Icom 735 with a Bird 4381 power analyst in line
(which reads PEP directly). I also verified the wattmeter readings using an
o-scope. The power didn't start to drop til the voltage dropped below 10.5v
and I was able to receive just fine all the way down to 9.5v. Below that the
rig started to die.

Eric

"Bruce in Alaska" wrote in message
...

It is commonly understood that for each volt dropped from 13.6 VDC
at the radios PowerAmp DC Terminals, you lose 50% of your PEP Power.
So if your at 13.6 Vdc you get your 150 PEP, and at 12.6 VDC you
get 75 PEP, and at 11.6 Vdc you get 35 PEP and below 11.0 VDC
the internal Voltage Regulators drop out of regulation and the
radio goes OFF.

It is not a Myth, is is a Fact, and as others have stated, your
experiment doesn't prove, or disprove the fact. Also, as Larry
stated the 21st Century Icom Rigs have a lot more headroom in the
SolidState Amps than just about any other Marine MF/HF Radio,
just to deal with this cause. Just try your experiment with ANY
SGC designed and built radio.

Bruce in alaska I am Old School, and an Old Fart, and I do remember
back in the Old Days, before Autotuners, allowed
anyone to think they were World Class Radiomen...
--


Oh, my gosh, it's just killing me to sit here without jumping in! Then
when I heard SGC mentioned, I knew that someone besides me had experienced
"Bruce's Law". I am compelled to defend his position and scientific
observations without reservation.

How much midnight oil I've spent working on the DC supply system on
"commercial" vessels, trying to reduce the voltage drop. Until the "code"
made batterys in the pilot house almost mandatory, can't you imagine running
an SGC711 from engine room batterys? Here's a typical example (it is a
genuine "commercial", by the way) of a vessel still using this one time
popular rig:

http://www.alaskaboat.com/sn033.htm

Those SGC711's were hard to coax to even 75 watts PEP with any wire
less than #4 if you were more than two feet away from the battery! (OK,
stretching a little here) And the built-in wire antenna tuner was a charmer,
hey? But as the URL and dozens more can show, that not everyone has yet to
install an Icom M802.

Some earlier SEA's and Icom's with first generation digital VCO tuning
were cool, too. A sneeze or laugh in the mic was as apt to change channels
as anything if the antenna was fed directly from the radio, and some joker
installed #10 wire for DC power!

Early automatic antenna tuners were (are) cool, too. A little pitching
and rolling in the North Pacific and they would lock up and refuse to even
try to tune anymore. Then the transmitter's fabulous SWR power foldback
circuit hit the fan and 5 to 10 watts could be used to heat up the tuner's
coils and capacitors. (condensers, actually)

Lots of this early stuff is still out there. By the thousands. Modern
marine SSB radios certainly have improved their ability to survive poor
installations, but is that any reason to go as cheap as possible with DC
wiring and antenna installations? (RF ground on "Tupperware" boats is
probably just as important, but I digress)

Old Chief Lynn

(besides, tubes help heat the pilothouse and ease aching joints)

Let's just watch out here. I was in a junk shop a while ago and I told
the proprietor what was actually hoping to find. We got talking about
ships and boats. He stopped and asked if I could tell him about
something in back. When retrieved, it turned out to be a marine HF -
real live dinosaur (dynosoar?). I think is was Hammerlund or EF Johnson
- most of the crystals had been pulled, but it still had a the 2 1625s
in the final (and a little burned spot on the tank). I looked at him
and said "You know - They haven't made 'em like this for a long time".
(Aren't we glad!)

Matt Colie - Lifelong Waterman, Licensed Mariner and Perpetual Sailor
  #9   Report Post  
posted to rec.boats.electronics
Bruce in Alaska
 
Posts: n/a
Default what size wire to use for 30amp 12v circuit ?

In article ,
Matt Colie wrote:

Let's just watch out here. I was in a junk shop a while ago and I told
the proprietor what was actually hoping to find. We got talking about
ships and boats. He stopped and asked if I could tell him about
something in back. When retrieved, it turned out to be a marine HF -
real live dinosaur (dynosoar?). I think is was Hammerlund or EF Johnson
- most of the crystals had been pulled, but it still had a the 2 1625s
in the final (and a little burned spot on the tank). I looked at him
and said "You know - They haven't made 'em like this for a long time".
(Aren't we glad!)

Matt Colie - Lifelong Waterman, Licensed Mariner and Perpetual Sailor


A lot of the OLD Northern Radio Co. AM Sets had 807/1625's in them.
when I started at Northern, we still were servicing those and I have
very fond memorries of traveling all over the State of Alaska, hauling
a RCA Tube Caddy full of 807's, 1625's, 811's and an 813 or two....
I even remember when we used 866A's in the Power supplies, as
Recitifiers.

Bruce in alaska
--
add a 2 before @
  #10   Report Post  
posted to rec.boats.electronics
Bruce in Alaska
 
Posts: n/a
Default what size wire to use for 30amp 12v circuit ?

In article ,
"Lynn Coffelt" wrote:

Oh, my gosh, it's just killing me to sit here without jumping in! Then
when I heard SGC mentioned, I knew that someone besides me had experienced
"Bruce's Law". I am compelled to defend his position and scientific
observations without reservation.

How much midnight oil I've spent working on the DC supply system on
"commercial" vessels, trying to reduce the voltage drop. Until the "code"
made batterys in the pilot house almost mandatory, can't you imagine running
an SGC711 from engine room batterys? Here's a typical example (it is a
genuine "commercial", by the way) of a vessel still using this one time
popular rig:

http://www.alaskaboat.com/sn033.htm

Those SGC711's were hard to coax to even 75 watts PEP with any wire
less than #4 if you were more than two feet away from the battery! (OK,
stretching a little here) And the built-in wire antenna tuner was a charmer,
hey? But as the URL and dozens more can show, that not everyone has yet to
install an Icom M802.

Some earlier SEA's and Icom's with first generation digital VCO tuning
were cool, too. A sneeze or laugh in the mic was as apt to change channels
as anything if the antenna was fed directly from the radio, and some joker
installed #10 wire for DC power!

Early automatic antenna tuners were (are) cool, too. A little pitching
and rolling in the North Pacific and they would lock up and refuse to even
try to tune anymore. Then the transmitter's fabulous SWR power foldback
circuit hit the fan and 5 to 10 watts could be used to heat up the tuner's
coils and capacitors. (condensers, actually)

Lots of this early stuff is still out there. By the thousands. Modern
marine SSB radios certainly have improved their ability to survive poor
installations, but is that any reason to go as cheap as possible with DC
wiring and antenna installations? (RF ground on "Tupperware" boats is
probably just as important, but I digress)

Old Chief Lynn

(besides, tubes help heat the pilothouse and ease aching joints)


Ah Oh, I feel a Story coming on....

StonerWatts .... A Real Tale about MF/HF Marine Radio......

Years ago, I was working for Northern Radio, as a Field Tech/Radioman
and getting the Alaska State Ferries ready for their Annual SOLAS
Inspections. The State wanted to replace the venerable Northern N550
MF/HF SSB Radios with something totally SolidState, and had put out
the refit for BID. Well Don Stoner, and his partner PeeAir Gorrale,
wanted to get their SGC711 into the US Market, so they bid the job
really LOW, and got the contract to refit all the State Ferries.
Their guys did the installations, and had left the vessels, for
me to get them thru FCC/SOLAS Inspections. I did everything else, first
and left the MF/HF Radio's for last, and when I finnally got around to
doing the preinspection testing, found that all but one wouldn't meet
Frequency Tolerance, and NONE of them would meet PowerOutput Requirments,
using the accepted Testing Procedures, expected by the FCC Field
Engineers, of the day. I got ahold of the Port Captain, and explained
the problem, and since these radios were NEW and under Warrentee (sp)
that it was SGC's problem to rectify, but since the Inspection was setup
for the next morning, SGC better get their collective Ass in gear, or the
ships would fail the Inspection and not be ready to sail on schedual.
SGC was summoned and one of their Field Techs reset all the Crystal
Frequencies and did his best to get the Power Output up to spec's.

They worked all night on the first boat due for inspection, and when I
showed up, one hour before Inspection time, the Power problem still
wasn't resolved. Finally, the Tech, called his office and Don Stoner,
drove out, and showed up just as Bob Zinns, the FCC Engineer, did and
they came aboard together. While Bob and I went thru all the other
Inspection Items, don worked on the 711. After 2 hours, Bob and I were
ready to do the MF/HF Radio Inpsection, and we were presented with Don
Stoner, and his very expensive Tek Storage OScope, connected across a 50
Ohm Dummy Load, and he said he would demonstrate the Power Output of the
711 with this Test Setup. Mr. Zinns looked very skeptical, and I didn't
say a word, but Don proceeded with his demontration. He picked the Mic
and mashed the PTT and sope the test phrase "Five, five, five", into the
mic. He had the Storage Oscope set to capture the Peak Voltage Pulse of
the transmission, and then showed the assembliadge the reading, and got
out his calculator, and computed the PEAK Envelope Power for that, very
narrow Pulse. "Yup" he said, "just exactly 152 PEP Watts". Mr Zinns
asked hm to demonstrate that on a Peak Reading Bird WattMeter, and Don
stated that he would not, that his demonstation was sufficent. Mr Zinns
took out an 801 PinkSlip and Failed the vessels SOLAS Inspection, citing
the lack of spec'd Transmit Output Power. I tested the radio, in the
accepted way using a Bird Wattmeter, and found that we could get maybe
80 Watts PEP out of it with a Maximum Scream in the Mic. Everyone went
home and the FCC and SGC had a WAR of Fax's and Phonecalls, between the
Seattle Field Offce, FCC Headquarters, State of Alaska Ferry Systems,
Port Captain, and SGC, ect. After three days of this, it was determined
by the FCC's Chief Engineer, that Don Stoner's method of testing did in
fact prove that the radio was in compliance, and that the FCC Field
Offices would accept that method of testing, for the SGC711 only, and
Issue SOLAS Certificates for the Alaska State Ferries which had SGC711
Radios fitted.
The long and short of the story is: All the SGC's were stripped off all
the Alaska State Ferries within 6 Months, for the simple reason that
they couldn't talk to any of their regular BaseStations, on a consistant
basis, as they were used to doing with the N550's previously fitted.
All were replace with Icom's first generation MF/HF Radios that actually
would "Whistle up" to 150PEP on a Wattmenter. Northern Radio continued
to do all the FCC/SOLAS Annual Inspections, untill I left the company.
The State of Alaska Communications Shop, took over the job
and was still doing it when I joined the FCC a few years later, as the
Southeastern Alaska Resident Field Agent and started doing the FCC/SOLAS
Inspection on the Alaska Ferries as the FCC Inspector.
The StonerWatts Story is still around in FCC Lore, and told in Marine
Radio Shops, all around the North Pacific.


Bruce in alaska just cause you can see the spike on a scope doesn't
mean you can actually talk to someone......
--
add a 2 before @


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