Hang on for a week or two. The minima started as a spectrum analyzer. I should probably get back to it soon and publish the design. - f Sent from BlackBerry® on Airtel -----Original Message----- From: Paul Chebi <paul.chebi@xxxxxxx> Sender: minima-bounce@xxxxxxxxxxxxx Date: Mon, 24 Feb 2014 00:18:44 To: minima@xxxxxxxxxxxxx<minima@xxxxxxxxxxxxx> Reply-To: minima@xxxxxxxxxxxxx Cc: minima@xxxxxxxxxxxxx<minima@xxxxxxxxxxxxx> Subject: [minima] Re: A linear for the Minima Could somebody suggest/recommend a spectrum analyser that won't brake the bank? The more I read this and other groups it's becoming evident a S/A is an indispensable piece of testing gear for any serious builder/ ham Thanks 73 kk4ptv Paul Chebi Sent from my iPhone > On Feb 23, 2014, at 10:51 PM, Ashhar Farhan <farhanbox@xxxxxxxxx> wrote: > > 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> 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 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> >>> Sender: minima-bounce@xxxxxxxxxxxxx >>> Date: Sun, 23 Feb 2014 14:07:50 >>> To: <minima@xxxxxxxxxxxxx> >>> Reply-To: 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 >