Home made 6m amplifier with GI7B, by F5MAG

| In French (original) | En Espa?l |

(English translation provided by F5MAG, not responsibility of DXMAPS.COM)

Hello and 73 are described below my amplifier HF equip three GI7B the project to start by browsing the web I see cites yu1aw without which this project will never be successful electronics business I do not know the characteristics of the lamps and Small tricks I do not know Then I quote visit our friend JH0WJF consultant to the article I decide to start with the chassis

Then begin the mechanical difficulties it is indeed the greatest difficulty HF amps are the mechanical strength because of the student temperature, ventilation, vibration we must not forget that there are equal filaments vibration breaks I start with the greatest courage as you know mounts the simplest triodes are a cause of mounting since the first mechanical support lamp is simply a hole diameter of the grid lamp But still the problem of ventilation but there is not enough progress for the moment

After pierced and set three lamps seen here is the three beautiful girls hi as planned I also set the self shock and bypass for the high-voltage

You'll see the trait that determines the separation of high-voltage compartment

Below are the patterns published on the web by JH0WJF

After watching this mounting quite simple but very functional I launch area has a small modification assembly has the base was scheduled for GI6B in absolute months are identical but powerful Here patterns bitter modification only in the polarization of cathodes

The transistor used is simply a tip36 and zener diode and 41 volts that it allows a good polarization of three tubes Not finding tubes ferrites for shock filament I realize ca with a torus here is the photo I realize ten spires then split a can of bakelite to fix ca in the lower compartment cathodes you will notice the copper foil for putting aa mass of decoupling capacitors and pass by

The cathodes are surrounded by a collar of copper to facilitate welding because this place has the gold cathode operation and raise the temperature why it is imperative to make the paste and shake for the vibration and temperature The lamps were placed in a single filament for two days without the high voltage to run and then been here about ten hours with cathode polarization, tension filament, and finally the high voltage a thousand volts that it finally accustom lamps a function because they are surplus of the Russian army which we do not know the origin and date of manufacture Attention handling this very important and we must make it absolutely

To feed the filaments of lamps I chose a power supply switcher 12 will 13v adjustable soft START which to start slowly to protect lamps Then the circuit 'entry is a classic that the same assembly that our friend JH0WJF Here is a small glimpse of mounting input circuit that allows to adapt the impedance for a tranceiver

This is a good compromise for use tx trade with this system filter is eliminated at the same time the harmonic s An important issue is clean while the band six metres is not often overloads

Then we will move symbol output circuit which is very simple to have calculated the fierce resistance of the three lamps About 1200 of 1.2 ohms k for the three lamps to apply the law ohms during tests here is what I have seen Using my mfj 259 on the frequency indicate I can pay my impedance plate in very good condition Of course this test done on my offices in the absence of any tension attention voltage 2500 v very dangerous and you may kill I advise you to be very careful unload the capacitor thereafter and short-circuit the two terminal + and - to avoid a violent shock

I recommend you not to play with the high voltage that you are not a specialist


Here it is done now that my circuit is ready we will begin assembling

Here is the dangerous part of the amplifier HF

The high voltage

Here is the high-voltage generator for testing before the start

A small test vacuum with a probe divide by 10 manufactured by f1btm Below are the measuring instruments and IP ig

All this home made

Here is almost finished assembling you remarquerais the capacitor plate manufacturing house also

Voila almost finished

Here's my little lab

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