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 @

"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

"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)

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

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 @

Bruce in Alaska wrote in news:bruceg-
:

I even remember when we used 866A's in the Power supplies, as
Recitifiers.



Yecch.....flashovers! Been there, done that....

Bruce, have you seen what an AM transmitter looks like, now? A 50KW AM
broadcast transmitter uses POWERTAB transistors for final output stages!

http://hawkins.pair.com/wabcnow/wabcn14.jpg

That little board puts out 1KW with 240VDC applied...

Amazing. A 50KW broadcast transmitter cooled with muffin fans....55KW from
the power company...50KW to the antenna!

On Thu, 02 Mar 2006 00:51:43 -0500, Larry wrote:


http://hawkins.pair.com/wabcnow/wabcn14.jpg

That little board puts out 1KW with 240VDC applied...

Do they put 50 boards in parallel?

Wayne.B wrote in
:

Do they put 50 boards in parallel?




No, it actually has something like 248 boards, in parallel. There is one
board that always puts out 100 watts, the only board turned on at the
negative 100% modulation peak. The other boards are controlled by a long
driver board mounted outside the RF shield and hooked to them with big
ribbon cables. The modulation audio simply turns all but the one on and
off as the audio waveform is converted to the digital data. With no
modulation, half the boards produce a 50KW output carrier. As the audio
waveform goes up, more boards switch in up to 100% modulation peak, then
back to half and down to only the one 100W output, then back up. The
output amounts to a sum of all these boards' square wave switching
output. The big square wave is sent to a tuned circuit that filters out
the harmonics with more low-pass filters to keep the neighbors happy.
The output, of course, is an amplitude modulated sinewave that is quite
smooth, considering it comes from a digitized square wave. Being
actually a switching power supply at the RF carrier frequency, the boards
are 95+% efficient like the power supply in your computer....making the
company VERY happy as the electric bill comes down from 130KW load, the
rest wasted as heat, to 55KW load with only 5KW of heat coming off with
simple cooling fans. Simply amazing switcher technology, considering
AM's analog roots. Harris has a pretty good lock on the market for AM
transmitters, now.

The boards come in 100W, 200W, 500W and 1KW power levels, I think.
Binary switching them as the audio waveform is digitized makes quite
small power steps hardly recognizable in the modulated output.

Listen to almost any clear channel AM station in the USA and you'll be
listening to a Harris DX-50 these days. Hell, WWL on 870Khz was on the
air through the hurricane with theirs....near New Orleans.

In article ,
Larry wrote:

Bruce in Alaska wrote in news:bruceg-
:

I even remember when we used 866A's in the Power supplies, as
Recitifiers.



Yecch.....flashovers! Been there, done that....

Bruce, have you seen what an AM transmitter looks like, now? A 50KW AM
broadcast transmitter uses POWERTAB transistors for final output stages!

http://hawkins.pair.com/wabcnow/wabcn14.jpg

That little board puts out 1KW with 240VDC applied...

Amazing. A 50KW broadcast transmitter cooled with muffin fans....55KW from
the power company...50KW to the antenna!


No, i really haven't kept up on Broadcast Engineering, since I left that
field in the late 60's, in a previous life. I understandf that some of
the newer Transmitters using Class D & E Amps are very efficent and
compact in the extreme, compared to what I was working with.

Bruce in alaska
--
add a 2 before @

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 @