Old Xmtrs, "Ancient Modulation" and Amps
 

Scott Dorsey wrote:
Randy or Sherry Guttery wrote:

I won't tell you that they are almost indistinguishable. But I will say
that S-units should be a valid comparison standard, at least with military
gear that _is_ calibrated in 6 dB increments.
--scott

On virtually all of the mil receiver's I'm familiar with (or remember
much about) the signal strength (carrier) meter is marked in dBs (not S
units). I know that some of the "conversion sets" (like the RAOs) had S
meters (though the meter was dropped after S/N200 of the RAO-6; and none
of the RAO-7 had a meter). R-390s, 390As and 391s are all dBs; as were
the 1051s.

Perhaps the newer ones (post 1980) have S-meters?

That's an interesting point - what military receivers --besides
conversion sets -- have "S meters" (i.e. actually marked in S units)?

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 Amps
 

"Scott Dorsey" wrote in message
...
John N9JG wrote:
That's BS! If what you have stated is true, no one would run more than 10
watts. Believe me, 20 dB is _very_ noticeable.

Sure, it's very noticeable. But, as someone running half a watt CW
these days, I can say that it's not everything.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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

Old Xmtrs, "Ancient Modulation" and Amps
 

Hi,

No real pitfall with a modern amp, as long as you get one
rated for continuous duty a.m. operation.
You need tubes with a lot of plate dissipation rating,
since a.m. linear is inefficent, maybe 25% carrier efficiency.
Look for a linear with ceramic tubes, a big blower
and a heavy-duty power supply.

You may need an rf power attenuator between the Ranger
and the linear. Most modern linear amps
produce 1500W peak output with only about 65w peak drive.
Your Ranger will produce 160W pep output in a.m. mode
(at 40W carrier). The linear will be producing 375W carrier,
at legal limit, so it will be almost 10dB more output
than the barefoot Ranger. With no modulation,
the linear's power input will be about 1,500 Watts
(assuming 25% efficiency).
A lot of heat will be dissipted from the linear's plates,
about 1,125 Watts.

A T-network made of 3 each 100W lightbulbs may be an OK
rf attenuator at the linear's input, so you don't overdrive it.

73,
Ed Knobloch






Lazy Senior wrote:
I recently acquired a Viking Ranger in nice working condx.

I am interested in using this on AM on 160, 80, and 40 mtrs. The Ranger
runs around 40 watts Am carrier output. I would like to get an amplifier
to use with this xmtr, maybe a vintage amp. What should I be looking
for? I would like to run legal Am Limit on these 3 bands. Should I
forget about Vintage Amps and get a modern Amp? Suggestions please. Any
pitfalls to using a modern Amp?

Thanx

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Amps
 

Edward Knobloch wrote:
Hi,

No real pitfall with a modern amp, as long as you get one
rated for continuous duty a.m. operation.
You need tubes with a lot of plate dissipation rating,
since a.m. linear is inefficent, maybe 25% carrier efficiency.
Look for a linear with ceramic tubes, a big blower
and a heavy-duty power supply.

You may need an rf power attenuator between the Ranger
and the linear. Most modern linear amps
produce 1500W peak output with only about 65w peak drive.
Your Ranger will produce 160W pep output in a.m. mode
(at 40W carrier). The linear will be producing 375W carrier,
at legal limit, so it will be almost 10dB more output
than the barefoot Ranger. With no modulation,
the linear's power input will be about 1,500 Watts
(assuming 25% efficiency).
A lot of heat will be dissipted from the linear's plates,
about 1,125 Watts.

A T-network made of 3 each 100W lightbulbs may be an OK
rf attenuator at the linear's input, so you don't overdrive it.

73,
Ed Knobloch

Ed
Thanx - this is one of the most usefull replys I have gotten on this
subject.

Lazy Senior

Old Xmtrs, "Ancient Modulation" and Amps
 

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

The current power limit for AM is 1500 watts PEP. This
means a carrier output of 375 watts. Easily obtainable
with the proper linear amp.

73, Roger


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Old Xmtrs, "Ancient Modulation" and Amps
 

Thanks for pointing this out. Unlike SSB, the legal limit for AM has been
reduced from what it had previously been.

"Roger D Johnson" wrote in message
...
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

The current power limit for AM is 1500 watts PEP. This
means a carrier output of 375 watts. Easily obtainable
with the proper linear amp.

73, Roger


--
Remove tilde (~) to reply

Remember the USS Liberty (AGTR-5)
http://ussliberty.org/

Old Xmtrs, "Ancient Modulation" and Amps
 

"Roger D Johnson" wrote in message
...
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

The current power limit for AM is 1500 watts PEP. This
means a carrier output of 375 watts. Easily obtainable
with the proper linear amp.

73, Roger




Roger

My point was, forget 10 or 20 dB improvement over a 40 signal.

Pete

Old Xmtrs, "Ancient Modulation" and Amps
 

I'll buy that. But, time and time again when on 40 meters SSB, as an
example, and running 100 watts, when the receiving station tells me that he
is having readability problems with my signal, then when I switch on the
Drake L-4B, the user almost always reports a significant improvement in both
received signal strength and readability. Going from 100 watts to 1000 watts
is 10 dB. Going from 10 watts to 1000 watts would be even more dramatic.

I still regard the statement that a 20 dB increase in signal strength is
"Not much at all" as pure Tier Scheiss.

" Uncle Peter" wrote in message
news:gKy9f.42576$fE5.26532@fed1read06...
[stuff]
My point was, forget 10 or 20 dB improvement over a 40 signal.

Old Xmtrs, "Ancient Modulation" and Amps
 

Randy or Sherry Guttery wrote:
Perhaps the newer ones (post 1980) have S-meters?

That's an interesting point - what military receivers --besides
conversion sets -- have "S meters" (i.e. actually marked in S units)?

best regards...

Why RT-718/FRC-93's, which are also know as KWM2A's do.

-Chuck

Old Xmtrs, "Ancient Modulation" and Amps
 

Chuck Harris wrote:

Randy or Sherry Guttery wrote:
Perhaps the newer ones (post 1980) have S-meters?


That's an interesting point - what military receivers --besides
conversion sets -- have "S meters" (i.e. actually marked in S units)?

best regards...


Why RT-718/FRC-93's, which are also know as KWM2A's do.

Don't those count as "conversions" - i.e. civilian sets "badged" with
military nomenclature?

I'll try asking again... what radios designed by / for the military (as
opposed to rebadged civilian sets) have carrier meters marked in S Units?

David - you've got a ton of mil stuff... what has meters in S units?

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