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.

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)

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)

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)

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

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

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

K7JEB wrote:

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

Jim
What linear amp do you use?

Lazy Senior