Re: A friendly suggestion for Farhan.


Maybe the next logical step is to convince Ashhar that instead of a new radio, his next offering should be the uBitAMP.

On 5/16/2018 11:51 AM, Ralph Mowery wrote:
There seems to be many amplifiers on ebay that put out about 70 watts for around $ 25 to $ 50.  Those are just circuit boards with parts mounted or kits. No filtering that you would have to add and a TX/RX switch and box to put it in. Going much about 10 watts would seem to knock it out of the portable weight limit .  I was talking with some friends on 80 meters this morning and using the 16 watts I get out (after the transistor mods) to drive a Drake L4B amp to somewhat over 150 watts out and getting good reports.

I am glad this rig is on the market as is.  Gives me a chance to make some modifications and my main goal is to use it with some transverters that need about 5 to 15 watts of drive depending on which one I use.

I am not much for designing things, but do enjoy playing around with others ideas.

de KU4PT

On Wed, May 16, 2018 at 11:30 AM, ajparent1/KB1GMX <kb1gmx@...> wrote:
One possible solution for those that want power....
Whats funny is I have built many QRP radios, I mean something over 10 of them all SSB.
Generally if the 3-5W didn't do it then 100 might have.  At one point I decided an amp
was a solution so I built it and it works well, though rarely use it.  Why, I find I make
contacts at lower power and when I cannot 100W isn't enough.  

One thing building an amp that works and doesn't fry everytime you look at it is on face trivial.
At the same time its about as non trivial as one can get.  A good amp is a mechanical project
as you are managing heat and sometimes much more than guessed.

The next possible increment up is not 20W:
If your inclined look in the files area of this forum under KB1GMX, there are two files called
HF-use-Fet 1 and 2.  Its fairly simple and if built well its a solid amp.  Pay attention to the
mechanical build.  Its a 1-2 watts in for more than 40-50 out amp for all HF using two IRF510s.
I didn't design it but I can say that if you build it soldering and mechanical construction has
to be 100% and there are the tribal tricks not written up that need to be known.  An aside if
you cannot cut aluminum pieces and drill and tap holes your already on the short side 
skills required.   To farm out machine shop work is expensive even in bulk.

The path to 100W is not cheap:

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