Steve says in Message: 3
Date: Sat, 7 Oct 2017 10:32:17 +1300
From: Steve Wright <stevewrightnz@gmail.com>
To: amps@contesting.com
Subject: Re: [Amps] SB200 on 30 m
Message-ID: <346cad54-63df-7c3b-4dfb-e0508b8cf90c@gmail.com>
Content-Type: text/plain; charset=utf-8
On 07/10/17 10:07, Michael Clarson wrote:
[...] Besides the 3 dB, he'd get better match to exciter, better
harmonic suppression, and,better efficiency which is easier on the
tubes and power supply. Probably only changing taps on coils and maybe
a capacitor or two in grid circuit. Easily reversible mods.
That's OCD levels of daft.? No one in their right mind goes through
those hoops for 3dB, and all this better matching and harmonic
suppression is just virtue signalling.? A simple rotatable dipole will
give you your 3dB, AND it works on receive.
This is all assuming the mods DO go smoothly, and the amp still
functions at full output on 80 and 40, which wasn't power to begin with
- the SB200 is only a 600W amp on 80/40/other so why bother?
S
@ Mike:
Agreed about the efficiency, tube life, better match, etc.
@Steve:
Not everyone lives on a piece of land or has a situation that would allow a 30m
rotatable dipole. Here on my postage stamp sized city lot the only realistic
direction is UP. And so my vertical sits upon my 160 foot of chain link fence
and does a credible job.
Also… remember I’m heading to 300w not 200w with this mod and that’s 4.77db
compared to a barefoot 100w. But, my tired old pro3 only puts out 75W so the
comparison for moi is really 10xlog(300/75)= 6.02db over my running barefoot on
30. Six db is nothing to sneeze at, eh?
With respect,
jerome - VA7VV/VE7ASS
Vancouver
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