My Linear is a class AB1 high frequency amplifier utilizing the Eimac 4CX5000A power tetrode. It is operating on the 176m. A 4CX5000a will work in the circuit with little modifications. -->The Screen of the tube is physically connected to the ground.
HOME MADE LINEAR AMPLIFIER 4CX5000A
In order to achieve full power output over 10000 watts continuous carrier, an input power approximately 10 to 40 watts is required. If your delivers more output power, reduce the drive level.
For the amplifier RF output, I used an LC type connectors at the time of construction. The LC type seems to handle the power levels without any problems (so far!).
The linear has a very sophisticated tube protection circuitry, designed to protect excessive plate current, screen grid current, screen grid voltage, bias voltage, overdrive, SWR. The tube is also protected from excessive temperature by continuously monitoring the required airflow temperature. In case of any fault, the amplifier is automatically cut off. A resistor in the B+ circuit and a MOV in the screen circuit further protects the tube and the power supply from a possible tube internal flash-over.
A lot of attention was given to the design of the linear cooling system. A pressurized forced air cooling to achieve with a rugged temperature controlled 850 CFM blower (turbine) which effectively cools all critical components of the amplifier. The volume of cooling air far exceeds manufacturers' specifications for all critical components. The blower is positioned in such a way that it prevents hot air being circulated through the system.
Eimac SK-300A and Y-309 Bypassed socket for the 4CX5000A/10000D/15000A... series tubes.
Keep eyes on the screen current while tuning the PA. The screen current will go drastically negative (-10mA) if the cavity is tuned too low in frequency.
High-Voltage Power Supply.
keep your hands OUT!
HF BANDS QRP HI POWER LINEAR AMPLIFIER .An AM Transmitter Modification and Construction Project. -->
-->AM PLL TRANSMITTER EXCITER 522-1800KHZ -->PLL Synthesizer Variable Power Output,swr Protection. The Best For Radio Station!!
The 455 kHz IF utilizes crystal filters for 0.1 and 1 kHz bandwidths and mechanical filters for 2, 4, 8 and 16 kHz bandwidths. Operational capability of the receiver allows for remote control of the AGC and RF gain adjustments.
My R-390A is fairly complete, is in prety good shape, and works quite well.
The R390A/URR is without question the best receiver (in my opinion) mass produced.
Here are pictures of my Collins R-388/URR receiver.Collins Radio Company manufactured a lot of 51J3 and 51J4 receivers in the beginning of 1950's for the US Armed Forces, where they were called as R-388/URR and R-388A/URR.
I know Collins is a very respectable name in ham radio.
Data plate of my Collins R-388/URR
and here you can see the s-meter of this receiver.
The meter is calibrated in 20-,40-,60-,80-,and 100-db input signal levels and -10 to +6 db audio output level.
The R- 388/urr has a standard crystal filtering system. Only the 51J-4 version is equipped with the famous mechanical Collins IF filters, I consider the 3 and 6 kHz filters as very useful for AM reception, in some situations they are even better suited then the filters found in the R-390A.The receiver power supply can be operated from a 115 volt, 45 to 70 hz source and has provisions for 230 volt operation.
This unit was manufactured by Stewart Warner. A number of these units were manufactured by Collins.
Receiver: R-392/URR provides continuous tuning and calibration every 100 kHz throughout its range.
The receiver was designed with a watertight (!)
Icom IC -R8500 - Wideband Communications Receiver.
-->The Icom IC-R8500 Communications Receiver is probably the only receiver you will ever need, with superb coverage from 0.1- 2000Mhz in all modes SSB (USB, LSB), CW, AM, FM and WFM are included.
The ICOM's Audio Peak Filter is also very effective at helping voices to 'pop out' of the HF background noise."
The IC-R8500 is a high specification communications receiver ideal for the radio amateur.This handsome receiver is a terrific centerpiece or complement to any listening shack
More photo of SIEMENS E-311 receiver.E-311 Shortwave Receiver 1,5 - 30 mhz
-->Here's another favorite receiver.
MFJ-259B SWR antenna analyzer MODIFICATION 1.5-170 MHZ BY JOHN 5-19
In most of the US, mediumwave stations are separated by 10 kHz and have two sidebands of ±5 kHz. In the rest of the world, the separation is 9 kHz, with sidebands of ±4.5 kHz.
During the day, AM signals travel by groundwave, diffracting around the curve of the earth over a distance up to a few hundred kilometers from the signal transmitter. However, after sunset, changes in the ionosphere cause AM signals to travel by skywave, enabling AM radio stations to be heard much farther from their point of origin than is normal during the day.THE IONOSPHERIC WALL
Because of the solar ionization and also other smaller ionization effects as meteors, or even high energetic radiation from the space infinity, the ionosphere becomes a conducting wall that can reflect the waves, as light is reflected on a mirror.
More to follow..........Μην ανησυχείτε για το τι σκέφτονται οι άλλοι για σας γιατί απλώς οι άλλοι δεν σας σκέφτονται. Αναρωτιούνται μόνο τι σκέφτεστε εσείς για αυτούς. -->
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