Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Ok, the Modern Amp seems to be the way to go with an old AM xmtr, mainly
because they have 160 mtrs (THE band where higher power is almost
necessary)and also I can call a 800 number and get one fast.

Which amp is best for my circumstance?

I have a Ranger running 40 watts AM for drive.I want legal limit AM or
close to it with a modern Amp that can take it and not burn up because
of the duty cycle. Suggestions under $2500 new price please.

Which amp tube would be best for AM - 572's - 811's - 3-500's or the
high gain ceramic tubes?

Thanx

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy - Most modern amps being "linear" are not the way to go for AM as
they have poorer efficiency than the older Class C amps with high level
modulation. If you want an AM transmitter check out the ARRL handbooks
and ham ads for the 1950 to 1970s when AM was king.

Higher power on 160 is nice as the band can be noisy and the higher
power is needed to over come the noise level at the receiving end. BTW
- a way around this is to limit the receive bandwidth as with CW or
other slow speed forms of modulation and some most interesting work has
been done with very low power levels.

A problem you will find with older AM gear is that the manufactures
didn't support 160 meters years ago. The band had been taken over by
the government's LORAN A service during WWII and partly given back to
the hams with a 50 watt power lamination depending on where you lived.
Most hams didn't attempt to use 160 and this limited store bought
equipment.

If you have the room and technical ability might consider converting a
salvaged AM broadcast transmitter. They are available as most stations
are removing them to upgrade to much more efficient solid state units.

Good luck in your quest

73 Bob W7AVK

\

Lazy Senior wrote:


Ok, the Modern Amp seems to be the way to go with an old AM xmtr, mainly
because they have 160 mtrs (THE band where higher power is almost
necessary)and also I can call a 800 number and get one fast.

Which amp is best for my circumstance?

I have a Ranger running 40 watts AM for drive.I want legal limit AM or
close to it with a modern Amp that can take it and not burn up because
of the duty cycle. Suggestions under $2500 new price please.

Which amp tube would be best for AM - 572's - 811's - 3-500's or the
high gain ceramic tubes?

Thanx

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior ) writes:
Ok, the Modern Amp seems to be the way to go with an old AM xmtr, mainly
because they have 160 mtrs (THE band where higher power is almost
necessary)and also I can call a 800 number and get one fast.

No, and I don't know where you got that.

Nobody used a linear amplifier for AM in amateur radio circles.
They either used medium power to start with, or went with a full kilowatt
amplifier with suitable modulator. They made sure they had the space,
and made sure the floor was strong enough.

If your transmitter isn't powerful enough for you, then you find a more
powerful AM transmitter. If that's still not enough, then you build
or buy a full power amplifier or transmitter.

You won't get much power out of a linear amplifier because of
the way things work.

Just because nobody makes a kilowatt AM transmitter these days, and
you aren't interested in building one, does not mean a linear amplifier
is "the way to go".

Michael VE2BVW

Which amp is best for my circumstance?

I have a Ranger running 40 watts AM for drive.I want legal limit AM or
close to it with a modern Amp that can take it and not burn up because
of the duty cycle. Suggestions under $2500 new price please.

Which amp tube would be best for AM - 572's - 811's - 3-500's or the
high gain ceramic tubes?

Thanx

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Michael Black wrote:


Nobody used a linear amplifier for AM in amateur radio circles.
They either used medium power to start with, or went with a full kilowatt
amplifier with suitable modulator. They made sure they had the space,
and made sure the floor was strong enough.


You must not work AM. I talk daily on AM (with my Valiant)and find hams
running linear amps at legal limit. They ALL sound good. Most are
driving the amp with old xmtrs....

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:
Michael Black wrote:

Nobody used a linear amplifier for AM in amateur radio circles.
They either used medium power to start with, or went with a full kilowatt
amplifier with suitable modulator. They made sure they had the space,
and made sure the floor was strong enough.

You must not work AM. I talk daily on AM (with my Valiant)and find hams
running linear amps at legal limit. They ALL sound good. Most are
driving the amp with old xmtrs....

Folks are doing that today, but in previous years it was much more common
to run the transmitter with no modulation, and run it into a (very nonlinear)
amplifier running the legal limit. Then you'd modulate the finals of the
outboard amplifier.

The good part about this is that your amplifier is now much smaller and
has lower input power than a linear amplifier that is truly linear. The
bad news is that now you need a modulation deck putting out half as
much AF power as your RF output, and a gargantuan transformer.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:


Which amp is best for my circumstance?



Which amp tube would be best for AM - 572's - 811's - 3-500's or the
high gain ceramic tubes?

Thanx

Lazy Senior

Lazy:
People dont seem to read what you are asking - Suggestions for a modern
linear amp to be used on Am. --A simple question-- but everyone "wants"
to tell you it cant be done,shouldnt be done, or you dont need high
power,buy another xmtr, etc etc.

Yes, I Know people use Linear amps with old xmtrs, I have talked to many
of them.

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Bob W7AVK wrote:


If you have the room and technical ability might consider converting a
salvaged AM broadcast transmitter. They are available as most stations
are removing them to upgrade to much more efficient solid state units.

Yup - a Harris MW1 would be ideal... save for the power transformer(s)
nearly everything else can be either hand made (coils, etc.) or bought
off the shelf (transistors, etc.- including the PAs). The "output" unit
consists of 13 identical RF modules twelve as PAs - one a driver. They
"normally" run a 83W each - if one dies - the matching network
effectively isolates it - the drive to the remaining PAs "steps up" -
and it stays at a KW. One of easiest to maintain transmitters around
(from both layout - and parts availability). PA B+ is (IIRC) something
like 70V - the modulators consist of two sections - one that passes the
70V (i.e. saturated at 0% modulation) - or ramps down towards cutoff
with negative modulation- the other section of the modulator is tied to
+140V - and as positive modulation is applied - it overrides the 70V
rail - and up it goes pulling the PAs with it. Capable of 110% positive
modulation if everything is up to snuff. Each of those 13 identical PA
modules includes it's modulator (both sections). Very efficient for an
AM transmitter.

best regards...
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:

Lazy:
People dont seem to read what you are asking - Suggestions for a modern
linear amp to be used on Am. --A simple question-- but everyone "wants"
to tell you it cant be done,shouldnt be done, or you dont need high
power,buy another xmtr, etc etc.

Yes, I Know people use Linear amps with old xmtrs, I have talked to many
of them.

Well, yes, but you can use ANY modern linear amp, just as long as it is
rated for full power at AM.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior

Lazy:
People dont seem to read what you are asking - Suggestions for a modern
linear amp to be used on Am. --A simple question-- but everyone "wants"
to tell you it cant be done,shouldnt be done, or you dont need high
power,buy another xmtr, etc etc.

Yes, I Know people use Linear amps with old xmtrs, I have talked to many
of them.

Lazy Senior



Ya know... You specifically asked what type of "linears" would have
been use back when AM the common mode. Your question was
answered. Now your starting with the backtracking BS about
a modern "amplifier."

If you "know" people who are using linears with old
xmtrs", why not just ASK THEM WHAT THEY ARE
USING and quit trolling this newsgroup
with your BS?

Peter k1zjh

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Uncle Peter wrote:


If you "know" people who are using linears with old
xmtrs", why not just ASK THEM WHAT THEY ARE
USING and quit trolling this newsgroup
with your BS?

Peter k1zjh


Same old crap from usenet, its why I hardly use it for getting info. Too
many assholes like you. Self Proclaimed experts always call you a troll
when they cant supply you with usefull info.

If you think I am trolling just put me on your kill list, I wont miss you.

I asked a simple question, you just gave me bul**** answers. Most of the
really good replys I got via email.

Dont bother replying I am not looking for a flamefest....

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Same old crap from usenet, its why I hardly use it for getting info. Too
many assholes like you. Self Proclaimed experts always call you a troll
when they cant supply you with usefull info.


Crap in, crap out. I still think you're a CBer trolling. I say it again,
why
not ask all of your AM buddies who you state are running linears??????

The BS meter is pegged.

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Uncle Peter wrote:

The BS meter is pegged.


Is that why the call you use "Peter k1zjh" is fake? From Qrz. com - The
callsign K1ZJH is not in our database.

You gonna use a callsign make sure it is valid - just like this response:

.................................................. ...........
Uncle Peter wrote:

The problem is a ham linear will not deliver 1000 watts carrier
power on AM. It would have to be rated for 4kW to do so.
PEP on AM is at least 4X carrier.

Pete

.................................................. .....................

Everyone knows cept you that legal limit AM is 375 watts carrier...

I just dislike self proclaimed "experts" that know little and show it on
usenet under fake calls.

You made a real fool of yourself this time Peter k1zjh......

And YEAH, I got a ham license, all those nice private emails I received
with thoughtfull answers, got my call....

Lazy Senior (no fake call - you wanna know who I am - private email me)

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:
Uncle Peter wrote:

The BS meter is pegged.

Is that why the call you use "Peter k1zjh" is fake? From Qrz. com - The
callsign K1ZJH is not in our database.

You gonna use a callsign make sure it is valid - just like this response:

The FCC thinks it's valid. Whether or not it's in QRZ.com is irrelevant.

--
Mike Andrews W5EGO

Tired old sysadmin

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Mike Andrews wrote:



The FCC thinks it's valid. Whether or not it's in QRZ.com is irrelevant.


Hmmm, a new nocoder vanity call? No, most tech lites I know have common
sense, Uncle Peter acts like an Extra.........

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:

Is that why the call you use "Peter k1zjh" is fake? From Qrz. com - The
callsign K1ZJH is not in our database.


From the FCC website:

Federal Communications Commission

Callsign Results [ULS DATABASE]

Callsign K1ZJH
File Number 9504040209
Applicant Type I
Service HA

Licensee Name BERTINI, PETER J
Address 20 PATSUN R
City SOMERS
State CT
Zip 06071-1810
Operator class E

IIRC - that last item is Amateur Extra?

Then there is:

http://www.cq-vhf.com/Log%20Periodic.html

Now who looks "the fool"?
Sheeesh...
--
randy guttery
P1-8-14610 (I'll save ya' the trouble of looking that up, since you seem
"look-up impaired" - that's FCC License Radio Telephone First Class
w/Ships RADAR issued 5/30/78 - converted to FCC PG-8-4546 current and
active).

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Randy or Sherry Guttery wrote:




Now who looks "the fool"?
Sheeesh...

Unlike our USA President, I admit my mistakes. I was a fool responding
to Uncle Peters flame. He was nasty to me first. I simply was looking
for intelligent answers to maybe stupid questions but answers to things
I didnt know - Peter called me a troll - not true -I am just a average
stupid ham trying to learn.

I truly thank everyone who tried to help me - and there were many
private emails. Thanx to all cept Peter.

Only Peter tried to ridicule me and I apologize for taking his bait.

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior ) writes:
Uncle Peter wrote:

The BS meter is pegged.


Is that why the call you use "Peter k1zjh" is fake? From Qrz. com - The
callsign K1ZJH is not in our database.

You've missed a lot if you don't recognize his name and callsign.

He had quite a number of articles in QST, including a synthesized 2meter
rig in the early seventies, when synthesizers were still a new thing
in the ham magazines. Lots of VHF equipment too, and in Ham Radio
magazine also.

Wrote for Communications Quarterly, and in recent years, has a column
about antique radio in Popular Communications magazine.

He's hardly a "self-styled expert".

Michael VE2BVW

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:

Unlike our USA President, I admit my mistakes.

Plonk
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com

Old Xmtrs, "Ancient Modulation" and Modern Amps (Only in America)
 

Lazy Senior wrote:

Same old crap from usenet, its why I hardly use it for getting info. Too
many assholes like you. Self Proclaimed experts always call you a troll
when they cant supply you with usefull info.

If you think I am trolling just put me on your kill list, I wont miss you.

I asked a simple question, you just gave me bul**** answers. Most of the
really good replys I got via email.

Dont bother replying I am not looking for a flamefest....

Lazy Senior

Only in America - would grown men using $1,000 computers pay $30 a month
for the priviledge of lecturing someone about the "best" way to use an
80 year old technology.

Lazy Senior: I feel your pain!

If I were you, I'd look for any of the "2KW PEP" linears that come up on
Ebay or at hamfests, such as an L-4B: any linear rated for 1KW key-down
continuous input will work fine. If you have the money, a Collins 30S-1
would be my "top shelf" choice. I recommend you avoid the "1KW PEP"
units, such as the Collins 30L-1, since they're designed for SSB.

If you are using coax, don't forget to check it for breakdown voltage
before loading up: AM peaks will put a lot of strain on older cable.
Don't ask me how I know ;-).

HTH.

William

--

William Warren

(Filter noise from my address for direct replies)

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Linear amplifiers are not new to radio. They were used in the thirties -
yes to amplify am transmitters. It is old technology, and perfectly proper
to put out a signal that way.

When you compare efficiencies of a linear amplifier to a full blown class C
plate modulated amplifier, you must consider the filament and plate power of
the modulator.

I worked a number of stations in the fifties that were running a low level
transmitter into a linear amplifier, and they sounded excellent. The
Central Electronics 100V and their linear amplifier put out an excellent AM
signal. Even the KWS-1, which transmitted AM using only one sideband,
sounded great.

The modern amp covers 160, though, along with the other bands, so of one is
lazy (hence his name), the linear is a reasonable approach.

Colin K7FM

Old Xmtrs, "Ancient Modulation" and Modern Amps (Only in America)
 

William Warren wrote:


Lazy Senior: I feel your pain!

If I were you, I'd look for any of the "2KW PEP" linears that come up on
Ebay or at hamfests, such as an L-4B: any linear rated for 1KW key-down
continuous input will work fine.

If you are using coax, don't forget to check it for breakdown voltage
before loading up: AM peaks will put a lot of strain on older cable.
Don't ask me how I know ;-).

HTH.

William


William

Thanx for the info. It seems like most hams I work on AM that use amps
are using linear amps, but much to my surprise there are many here in
this group that are against using linears.

Lazy (yes) Senior (yes)

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

COLIN LAMB wrote:

The modern amp covers 160, though, along with the other bands, so of one is
lazy (hence his name), the linear is a reasonable approach.

Colin K7FM



Colin
This is what I suspected when I first asked my question, but many
posters here infered it was not a reasonable approach.

Thanx
Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

Lazy Senior wrote:
Mike Andrews wrote:

The FCC thinks it's valid. Whether or not it's in QRZ.com is irrelevant.

Hmmm, a new nocoder vanity call? No, most tech lites I know have common
sense, Uncle Peter acts like an Extra.........

THat's because he's an Extra.

I'm not sure where you're getting your data, but the FCC has this for
Peter:

Licensee Name BERTINI, PETER J
Operator Class Amateur Extra

You _could_ have looked it up for yourself.

--
Mike Andrews, W5EGO

Tired old sysadmin

Old Xmtrs, "Ancient Modulation" and Modern Amps (Only in America)
 

Lazy Senior wrote:

William

Thanx for the info. It seems like most hams I work on AM that use amps
are using linear amps, but much to my surprise there are many here in
this group that are against using linears.

Lazy (yes) Senior (yes)


Well, you can go either way, but linears are simpler, self-contained,
easy to service, and they help keep the room warm.

High level plate modulation was "The way to go" before the FCC switched
to measuring output power instead of input, and I understand why some
hams would want to use Class C finals and high level modulation, since
that's the best way to get the most efficiency out of a 1 KW input rig.
Now that we measure output power, I don't feel that the added hardware
and maintenance of using high-level modulation is justified. Others may
disagree.

My attitude is "If it isn't fun, stop doing it" - this is a _hobby_, but
somehow a few hams never get the word. If having a "big iron" rig is
what turns you on, go for it. If you want to maximize efficiency and
homebrew a rig from scratch, there are Class E designs available using
computer components to good effect. If you're interested in a smaller
footprint and interoperability with SSB or other modes that need
linears, then a linear is a practical alternative.

FWIW.

William

--

William Warren

(Filter noise from my address for direct replies)

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

The modern amp covers 160, though, along with the other bands, so of one is
lazy (hence his name), the linear is a reasonable approach.
Colin K7FM

This is what I suspected when I first asked my question, but many
posters here inferred it was not a reasonable approach.
Lazy Senior

I use low-level modulation and a linear amplifier to work AM. My
advice in selecting a linear amplifier for that mode is to focus on
the heat dissipation capability of the final devices, be they tubes
or transistors. Although the theoretical efficiency of a class-B
amplifier is something like 67%, that applies to a signal swinging
the amplifier between cutoff and saturation. For the carrier-wave
level, which will be 1/4 the peak output power, the operating point
will be in the regions of the characteristic curves that are much
less efficient. I typically get 25-30% from my SB-220 with a
250-watt carrier output power. Worst-casing a desired 375-watt
carrier level with 25% efficiency gives a final-power-dissipation
requirement of 1125 watts - a stretch for a pair of 3-500's, somewhat
easier with a 3CX1200 and easier still with an 8877/3CX1500.
The steady-state power-supply requirements are also pretty strenuous -
1500 watts - although most recent designs (Ameritron AL-1500) are
capable of this.

The efficiency argument against using a linear and in favor of
high-level modulation is seen to be fairly strong. However there
are a few additional factors to consider: As noted by another
poster, the modulator has to be powered up and has its own efficiency
issues. Also, using a linear amplifier rather than a Class-C final
reduces the harmonic-attenuation problem considerably (as well as
neighborhood TVI complaints). Modulation done at low levels is
more "controllable" with modestly sized components for splatter
filters, negative-peak loading/clipping and negative feedback. I
use an SSB transceiver (a Kenwood TS-850) for the extreme form
of this "modulation control", since my transmit signal is passed
through the same 6 kHz IF filter used for reception - effectively
filtering out splatter and out-of-channel IMD. The last advantage
of linear amplifier use, stated in the beginning of this thread, is,
of course, the ready availability of commercial units, both new and
used. For a dual-mode station (AM and SSB), the investment in
the amplifier pays a double dividend while, at the same time,
breathing new life into (and a whopping signal out of) many cherished
vintage low-power AM transmitters.

Jim, K7JEB

Old Xmtrs, "Ancient Modulation" and Modern Amps (Only in America)
 

William Warren wrote:


My attitude is "If it isn't fun, stop doing it" - this is a _hobby_, but
somehow a few hams never get the word.

FWIW.

William


William
We think alike. Too many hams take hamradio way too seriously. Its not a
way of life, its just a small part of my life.

I am a long time ham -45 yrs-. After posting here for the first time I
was called a troll simply because I asked a stupid question which I
didnt know the answer to. Altho having been a ham for so long, I am not
particularly tech inclined.In other words my life doesnt revolve around
electronics and theory.I know fom experience many hams look down on
those who are only Tech lites or Generals. It is no surprise young
people dont want to join our ranks.

You were one of many who gave me a very informative answer in language I
could understand. I only wish more had your attitude.

Thanx and hope to CU on AM
Lazy Senior

Old Xmtrs, "Ancient Modulation" and Modern Amps
 

K7JEB wrote:

I use low-level modulation and a linear amplifier to work AM.

Jim
What linear amp do you use?

Lazy Senior