"Nordic Breeds WA4VZQ" wrote in message
...
"Antonio Vernucci" wrote in message
...
You are both right.

On a 1966 issue of QST magazine, I found the advertisement of "Echoplex"
by Kahn Research Laboratories. It sold for more than 300$, which was not
cheap at those times.

As to Lincomplex, I remember a friend of mine working for Page Europe who
told me having installed Lincomplex on HF transmitters in Africa.

73

Tony I0JX
Rome Italy

Thank you, Tony.

Somehow, I think you are talking about Leonard R. Kahn of Kahn Research
Laboratories in Freeport, Long Island, NY, and not A. Q. Khan of Khan
Research Laboratories in Kahuta, Pakistan (Pakistan's main nuclear weapons
laboratory as well as an emerging center for long-range missile
development). Leonard Kahn is best known for his paper: L.R. Kahn,
“Single Sideband Transmission by Envelope Elimination and Restoration,”
Proceedings of the IRE, Vol. 40, July 1952, pp. 803–806., and for his work
on AM stereo. Google somehow doesn't know the difference...

73, Barry WA4VZQ

Wow, isn't this a super thread? Learned more here in a week of spare
time than 60 years of experiments and reading magazines! Where was
Usenet when we needed it?

Old Chief Lynn, W7LTQ

Somehow, I think you are talking about Leonard R. Kahn of Kahn Research
Laboratories in Freeport, Long Island, NY, and not A. Q. Khan of Khan Research
Laboratories in Kahuta, Pakistan (Pakistan's main nuclear weapons laboratory
as well as an emerging center for long-range missile development). Leonard
Kahn is best known for his paper: L.R. Kahn, “Single Sideband Transmission by
Envelope Elimination and Restoration,” Proceedings of the IRE, Vol. 40, July
1952, pp. 803–806., and for his work on AM stereo. Google somehow doesn't
know the difference...

Yes, it was Leonard Kahn. I have an Kahn SSB adapter for 455-KHz IF receivers.
It employs a great deal of nuvistors. Very complex machine!

73

Tony I0JX

Antonio Vernucci wrote:
I am planning to build a suppressor-grid modulated AM transmitter.

In all the diagrams I have seen they use proper pentodes, i.e. tubes
that have a real suppressor grid (e.g. 803).

I have seen no diagram using beam power tubes (e.g. 813 or 814) which
have beam forming plates instead of the suppressor grid .

Before purchasing 803 tubes, I would like to be sure that 813s or 814s
are really unsuitable for suppressor-grid modulation.

My question is whether, with 813s or 814s, the plate current can be
actually controlled by varying the beam forming plates voltage.

Does anyone have experience on that issue?

73

Tony I0JX

Rome, Italy

A little late, but could be of interest:

Try the 2E22 valve.

I used to work with this excellent valve during my military service in
1968, repairing military equipment that used it as supresor modulated.

It was built especially for that purpose.

Here are the specifications:

2E22
Power Pentode

Base & Bulb
EIA Base 5J

Mechanical Data

EIA Base ...................................... 5J
Electrical Data

Heater Voltage ................................ 6.3 V
Heater Current ................................ 1.5 A
Direct Interelectrode Capacitances (approx)

Pentode
Input ......................................... 13 pf
Output ........................................ 8 pf
Grid to Plate ................................. 0.2 pf
Maximum Ratings (Design Center Values)

Pentode
Plate Voltage ................................. 750 V
Grid No. 2 Voltage ............................ 250 V
Plate Dissipation ............................. 30 W
Grid No. 2 Dissipation ........................ 10 W
Characteristics and Typical Operation

Class C Oscillator/Amplifier
Plate Voltage ................................. 750 V
Grid No. 3 Voltage ............................ 22.5 V
Grid No. 2 Voltage ............................ 250 V
Grid No. 1 Voltage ............................ -60 V
Grid No. 1 Current ............................ 6 mA
Plate Current ................................. 100 mA
Grid No. 2 Current ............................ 16 mA
Driving Power ................................. 0.55 W
Power Output (approx) ......................... 53 W
Characteristics and Typical Operation

Class C Modulated Amplifier (Supressor)
Plate Voltage ................................. 750 V
Grid No. 3 Voltage ............................ -90 V
Grid No. 2 Voltage ............................ 250 V
Grid No. 1 Voltage ............................ -90 V
Plate Current ................................. 55 mA
Grid No. 2 Current ............................ 29 mA
Power Output (approx) ......................... 16.25 W

Alejandro Lieber
LU1FCR
Rosario - Argentina

Real-Time F2-Layer Critical Frequency Map foF2 at:

http://1fcr.com.ar

Try the 2E22 valve.

I used to work with this excellent valve during my military service in 1968,
repairing military equipment that used it as supresor modulated.

Thanks for suggestion. I have some 2E22s, even some 2E24s (quick.heating
versions).

The problem with the 2E22 is that the output power would be small (probably 10W
or so) because, using suppressor screen modulation, the efficiency is rather low
(30%).

Using two 803s I can instead get 200W or perhaps 250W of carrier.

73

Tony I0JX

"Antonio Vernucci" wrote in message
. ..
Thanks for suggestion. I have some 2E22s, even some 2E24s
(quick.heating versions).

The problem with the 2E22 is that the output power would be small
(probably 10W or so) because, using suppressor screen modulation, the
efficiency is rather low (30%).

Using two 803s I can instead get 200W or perhaps 250W of carrier.

73

Tony I0JX

Hi Tony,

The 2E22 is a true pentode while the 2E24 is a quick heating filament
version of the 2E26. Both are beam power tetrodes and not suitable for
suppressor modulation. A pair of suppressor modulated 803's will deliver
approximately 100 watts of carrier.

73, Barry WA4VZQ

Hi Tony,

The 2E22 is a true pentode while the 2E24 is a quick heating filament
version of the 2E26. Both are beam power tetrodes and not suitable for
suppressor modulation. A pair of suppressor modulated 803's will deliver
approximately 100 watts of carrier.

73, Barry WA4VZQ

Hello,

Barry is right !

With 2 x 803, input power will be as far as 1,5 x 2 x 125 W = 375 W

and carrier power, about 125 W (33% of 375) only. No more !

All the best
Jean-Pierre (F6BGV)