[minima] Re: A linear for the Minima
- From: farhanbox@xxxxxxxxx
- To: minima@xxxxxxxxxxxxx
- Date: Mon, 24 Feb 2014 14:08:07 +0000
Sarmaji,
Higher power will also mean some other challenges.
1. We will need to use high voltage capacitors and more expensive toroids.
2. The core saturation of FT 37-43 will mean a different type of output network.
3. Proper dissipation of heat will mean an externally mounted heatsink.
Given all this, it is best to assemble something similar to the WA2EBY amp. I
have a much simpler 25 watts amp design. I shall clean it up and publish that
soon enough.
- f
Sent from BlackBerry® on Airtel
-----Original Message-----
From: Mvs Sarma <mvssarma@xxxxxxxxx>
Sender: minima-bounce@xxxxxxxxxxxxx
Date: Mon, 24 Feb 2014 19:17:11
To: <minima@xxxxxxxxxxxxx>
Reply-To: minima@xxxxxxxxxxxxx
Subject: [minima] Re: A linear for the Minima
perhaps we need to search for devices that have lesser Gcap
On Mon, Feb 24, 2014 at 7:16 PM, Mvs Sarma <mvssarma@xxxxxxxxx> wrote:
>
>
>
> On Mon, Feb 24, 2014 at 6:50 PM, Paolo Cravero <paolo.cravero@xxxxxxxxx>wrote:
>
>> About input gate capacitance, we are talking about:
>>
>> IRF510, 135 pF typ
>> IRFZ24: 370 pF typ
>> IRFZ44: 1770 pF typ
>>
>> While the latter two may be OK for 160/80 and maybe 40 m bands, driving
>> them on higher bands will be hard (too low impedance, see what Farhan wrote
>> yesterday).
>>
>>
>> What I love about this linear is that it can be built and tested while
>> waiting for Minima PCBs to arrive. Since we're dealing with higher level RF
>> I am afraid a PCB might require few revisions before becoming 100% stable
>> and reproductible. A Manhattan style is probably better for the
>> unexperienced.
>>
>> Mr Farhan, I hope you will publish a picture of existing Minima
>> Linear(s), as a guidance for those that will begin building it right away.
>>
>> 73,
>> Paolo IK1ZYW
>>
>>
>
>
> --
> Regards
> Sarma
>
>
--
Regards
Sarma
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