VHF Amplifier..

VK3ZL Amplifiers
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VK3ZL

VHF Amplifier..

Post by VK3ZL »

Hi all, I am currently using up some spare components to build a new VHF amplifier..This may be the last unit I can build for some time...Due to the low Aus$, importing new components have suddenly become expensive and I may have to add the cost to any new amplifiers I build after this unit..

Pics are a new "vacant" amplifier case and a GS-31B triode...If anyone is interested I can build this up as either a 6 or 2 meter amplifier...This will be suitable as a legal limit amplifier, or for use as an EME amplifier for those who have a high power permit...It should be good for at least 600 watts data,800 watts CW or 1KW SSB..The amplifier will be the same build style as those shown on my Logger page..

I can be contacted via email or phone 0355791403...

73...Bob..VK3ZL..
Attachments
Amplifier case with Papst fan and GS-31B tube.The Papst fan is a 12-28 volt unis rated at 285CFM free running...The air pressurises the RF deck and exits through the tube cooler and a Teflon chimney on the top cover..Under pressure there is more than adequate air for this tube...I use a multi tapped transformer so that  voltage can be selected for more or less air pressure.
Amplifier case with Papst fan and GS-31B tube.The Papst fan is a 12-28 volt unis rated at 285CFM free running...The air pressurises the RF deck and exits through the tube cooler and a Teflon chimney on the top cover..Under pressure there is more than adequate air for this tube...I use a multi tapped transformer so that voltage can be selected for more or less air pressure.
Another case view...The case is built using anodised aluminum..I clean the anodising away from all metal to metal joins in the RF deck so that there is good metal to metal contact..
Another case view...The case is built using anodised aluminum..I clean the anodising away from all metal to metal joins in the RF deck so that there is good metal to metal contact..
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VK6OX
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Posts: 276
Joined: Thu Mar 20, 2008 7:08 pm
Location: Perth NoR OF78vd

Re: VHF Amplifier..

Post by VK6OX »

Looking good Bob! 8)

Another fine example of your excellent amps in the making! :D
73
Andy VK6OX

If you can't explain it simply, you don't understand it well enough. Albert Einstein
VK3ZL

Re: VHF Amplifier..

Post by VK3ZL »

I have taken lots of time off due to illness however I have finally finished this amplifier and it has been sold..This amplifier was 2 meters with a 1/4 wavelength plate line output...Everything tuned perfectly at first switch on..With 25 watts drive it has in excess of 500 watts output and runs cool...The air flow noise is quite low using the 6 inch Papst fan running on 15vdc..Drive vswr through the T network is 1-1.I am really pleased with this amplifier and will pack it and send it to the new owner this coming week..This amplifier can be operated remotely via a PTT switch line.

I am hoping to complete the GS-35B 70cm amplifier soon along with my own small two band, 6 and 2 meter amplifier..This uses GS-9B triodes and will be loafing at 300 watts output..

The Australian dollar is staying around 90 cents and I now have to pay a lot more for importing tubes and transformers..This means that I have to add a few dollars on to my amplifiers ..I am currently having some health problems but I am anxious to return to my workshop..

73...Bob..
Attachments
HT power supply...This uses a 1350kva Toroidal transformer voltage doubled..
HT power supply...This uses a 1350kva Toroidal transformer voltage doubled..
Simple 1/4 wavelength plate line with link coupling on output..
Simple 1/4 wavelength plate line with link coupling on output..
Front panel hinges down for access to Step start, Bias system and 24 volt relay supply.
Front panel hinges down for access to Step start, Bias system and 24 volt relay supply.
My standard front panel layout..Plate and Grid meters, Bias set control and PTT etc..
My standard front panel layout..Plate and Grid meters, Bias set control and PTT etc..
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VK2ZRH
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Posts: 905
Joined: Mon Apr 09, 2007 2:17 pm

Re: VHF Amplifier..

Post by VK2ZRH »

Beautifully done, Bob. An absolute credit to your engineering nous and craftsmanship. :D
73, Roger Harrison VK2ZRH
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VK6OX
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Posts: 276
Joined: Thu Mar 20, 2008 7:08 pm
Location: Perth NoR OF78vd

Re: VHF Amplifier..

Post by VK6OX »

Wot Roger said above ...^ 8)

As a proud owner of one of Bob's VHF amps, I can only marvel at his efforts in producing such fine and AFFORDABLE devices.
My 6m 2 x GI-6b PA from Bob continues to perform exactly as Bob had designed it....robust and over-engineered for reliability. 8)

Thanks again Bob and well done!! :D :D
73
Andy VK6OX

If you can't explain it simply, you don't understand it well enough. Albert Einstein
VK4KHZ

Re: VHF Amplifier..

Post by VK4KHZ »

And Ditto.....

Get well soon Bob...you have plenty more of us to inspire!

Regards

Shane VK4KHZ
VK3ZL

Re: VHF Amplifier..

Post by VK3ZL »

VK4KHZ wrote:And Ditto.....

Get well soon Bob...you have plenty more of us to inspire!

Regards

Shane VK4KHZ

Thanks for the kind words Shane..I am looking forward to doing another project soon..

Bob..VK3ZL..
VK4WTN
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Posts: 154
Joined: Thu Jan 14, 2010 4:45 pm

Re: VHF Amplifier..

Post by VK4WTN »

Hi Bob, best wishes for your health, theres a few more amps in you yet. My 2 x GI7B amp is working like a dream
best wishes Wayne VK4WTN
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