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View Full Version : And yet another...2 meter GS-31B..



VK3ZL
10-19-2013, 04:49 AM
I had just delivered the last GS-31B 6 meter amplifier to it's new owner and I received mail from VK4 requesting a 2 meter unit..I collected the aluminum panels a week ago and started this new project last Monday..

This is pretty much after the same design as my last 2 meter GS-31B amp..The aluminum panels in this amp are anodised grey satin finish so I had to carefully remove the anodising from all metal to metal joins and earthing points so that the chassis was bonded together as a common ground...This was especially important around the RF deck...I used a high speed wire wheel to remove the anodising along all the joins down to bare aluminum, carefully, as I didn't want to disfigure the interior of the case...Using 12mm aluminum angle I re assembled the case and it looks pretty good..

The RF deck uses a 1/4 wavelength plate line grounded at the cold end...The Plate blocking capacitor is a 10kv/20kva doorknob 200pf...Hopefully the DC will never find it's way through that capacitor..

Plate tuning uses a grounded cam operated Flapper at the hot end of the Plate line and the Loading consists of a wire loop with a series to ground 20pf variable capacitor the other end goes to the output relay..

The Cathode circuit is simple, a tunable T network and can be adjusted from the back of the amplifier..

The front sub panel has a simple resistor relay step start for the high tension transformer..The tube bias setup uses a W4ZT designed board adjustable from the front panel and all the bias wiring, cutoff resistor/relay also on the sub panel..

I am about to wire in the front panel and will show further construction pics as I progress...I am held up waiting for a new batch of HT transformers and electrolytic capacitors but expect them soon..

Enjoy....Bob..VK3ZL..

KG4CGC
10-19-2013, 06:20 AM
Look at the bottom pic and disregard the concept of scale.
Now what are you looking at?
Interior back panel of a ___________________ .

VK3ZL
10-20-2013, 01:36 AM
Look at the bottom pic and disregard the concept of scale.
Now what are you looking at?
Interior back panel of a ___________________ .


Is this a bit better Charles....

Bob..VK3ZL..

VK3ZL
11-03-2013, 04:46 AM
Look at the last 6 meter thread I posted and you will find pics etc for the rest of this amplifier...Getting brain dead in my dotage...Sorry..

Bob..VK3ZL..

w2amr
11-15-2013, 05:28 AM
Beautiful work, as usual. :clap:

PA5COR
11-15-2013, 06:02 AM
Nothing braindead at that work and design ;) nice as ever.

W3WN
11-15-2013, 11:56 AM
Gorgeous work.

I'm sure that shipping costs would make sending one of these amps stateside prohibitively expensive... *sigh*

KG4CGC
11-15-2013, 12:51 PM
Is this a bit better Charles....

Bob..VK3ZL..

I meant it looked like a sub station panel at a couple of places I've seen. One of them being a bubble extrusion plant.

kk4rsv
11-22-2013, 11:41 PM
very nice work real ART

NQ6U
11-23-2013, 12:13 AM
very nice work real ART

He's a showoff, don't encourage him.

Just kidding, you're right. And welcome to the Island.

KG4NEL
11-23-2013, 10:12 PM
Bar's over that way. First drink is on the house.

VK3ZL
11-24-2013, 01:31 AM
This amplifier was completed a week ago and now resides in VK4..I have no new work at present so I am building a project for my own use...

Bob..VK3ZL..