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Re: [Amps] Looking for Alpha 87A expertise

To: amps@contesting.com
Subject: Re: [Amps] Looking for Alpha 87A expertise
From: Jim <jimw7ry@gmail.com>
Date: Mon, 15 Mar 2021 23:57:51 -0500
List-post: <mailto:amps@contesting.com>
Anything under 2ms  (2 milliseconds = 2000 microseconds, which is a whole bunch of nano seconds) is WAY MORE then enough for most transceivers. (Which was the point I was trying to make here).

BUT if you use an IC7000 or similar, you'll have trouble. But I think Alpha compensates for crappy radios that still transmit RF AFTER the PTT line is released.

See here:

https://www.w0qe.com/amplifier_timing.html


Thanks
73
Jim W7RY

On 3/15/2021 5:49 AM, Victor Rosenthal wrote:
There is a high-speed version of the 1N4007, the UF4007 whose recovery time is specified as 75 ns. That's pretty fast! See

<https://www.vishay.com/docs/88755/uf4001.pdf>

The regular 1N4007 is more like 30 us. Still fast.

<https://global.oup.com/us/companion.websites/fdscontent/uscompanion/us/pdf/microcircuits/students/diode/1n4004-general.pdf>

73,
Victor, 4X6GP
Rehovot, Israel
CWops #5
Formerly K2VCO
https://www.qsl.net/k2vco/

On 15/03/2021 4:57, Benjamin Deovlet via Amps wrote:
I respectfully suggest that you do a google search for the
specifications sheets for both diodes and do a comparison. Ben, W6FDU
In a message dated 3/14/2021 7:53:08 PM Pacific Standard Time,
ka4inm@gmail.com writes: On 3/14/2021 10:16 PM, Jim wrote:

Doug ...

How fast is a PIN diode?  How fast is a 1N4007 in an Alpha 87? If
you have not measured their speed, how can you make that
statement?

It is my understanding that the 1N4007 (only) IS a PIN diode and I
have used them to replace PIN diodes in relay-less 2 meter
transceivers up to 35. Watts and normal operation and power were
restored. Without failing.

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