Mac,
A. I meant that you can provide +24v to the FET instead of 12 volts.
This is the easiest way to get more more. I would imagine that you
will get about 10-15 watts of power. +24v smps (switching mode power
supply) are available quite cheaply on the net. Here's one that I
just located :
http://www.aliexpress.com/item/Original-MeanWell-50W-5V-24V-12V-Triple-Output-Switching-Power-Supply-NET-50D-UL-CB-SMPS/949336685.html
C. By a boot, I meant an external linear amplifier. Search for
WA2EBY's amplifier. Highly recommended.
- f
On Mon, Feb 24, 2014 at 9:03 AM, Mac A. Cody <maccody@xxxxxxx
<mailto:maccody@xxxxxxx>> wrote:
Farhan,
Thanks for your response. I don't understand a few things, though:
A. What are "24V smps"? Or do you mean "24V amps"?
C. What do you mean by "an external boot"?
I do not understand exactly what you mean by "on 7 and 3.5 you
could expect far greater power". Do you mean 7 MHz and 3.5 MHz?
73,
Mac AE5PH
On 02/23/2014 07:02 PM, farhanbox@xxxxxxxxx
<mailto:farhanbox@xxxxxxxxx> wrote:
Mac,
There are several ways to 10 watts.
A. Just use 24V on the IRF510's drains. The 24V smps are quite
cheap on the ebay, etc.
B. Use an RD16HHF10 inplace of the ol' IRF510. You will have
to use a trifilar winding in the final instead of the bifilar one.
C. Use an external boot(my current solution).
This amp is sort of non-scalable to higher power because of
the driver chain. The amp is extremely easy to build as it is
now. Being RC coupled, it is unreasonable to expect more than
3-4V peak from the drivers without substantial distortion.
That limits how much power can be drawn from the final PA.
Btw, on 7 and 3.5, you could expect far greater power from the
current configuration.
- f
Sent from BlackBerry® on Airtel
-----Original Message-----
From: "Mac A. Cody" <maccody@xxxxxxx <mailto:maccody@xxxxxxx>>
Sender: minima-bounce@xxxxxxxxxxxxx
<mailto:minima-bounce@xxxxxxxxxxxxx>
Date: Sun, 23 Feb 2014 14:07:50
To: <minima@xxxxxxxxxxxxx <mailto:minima@xxxxxxxxxxxxx>>
Reply-To: minima@xxxxxxxxxxxxx <mailto:minima@xxxxxxxxxxxxx>
Subject: [minima] Re: A linear for the Minima
Farhan,
Very nice design for the amplifier! I am curious, though, what it
wouldtake to boost the power to ten watts, so that the Minima
could
have a 'full gallon' for SSB QRP?
73,
Mac AE5PH
On 02/23/2014 05:34 AM, Ashhar Farhan wrote:
I just finished a linear amp that is entirely RC-coupled
except for
the power stage's output. I have built two of them and
they appear to
very quite stable and clean. It uses just the 2N3904s in
the chain
except for the power output stage.
The details are here http://www.hfsignals.org/index.php/RF386
It started with the a stupid question "Why can't the LM386
be used in
an RF linear?"
I am particulary curious to know what value should one
pick for the
100 ohms in the Q4. I am quite kicked by the one-line
band-switching
arrangement.
- farhan
