Topband: Fwd: Modifying Heath SB-200 for 160m

[Bill Tippett]

---------- Forwarded message ----------
From: Steve Ireland <vk6vz at arach.net.au>
Date: Nov 18, 2007 6:17 PM
Subject: Modifying Heath SB-200 for 160m

G'day

For some time, I have been rebuilding an old Heath SB200 linear
amplifier and adding 160m to it.  The amp is now working fine with one
exception – the 160m input (pi) network I am using gives a 3:1 SWR at
best.

This network I am using comes from a well-known article on modifying
linear amps to 160m, which is based on the Heath SB220 –
unfortunately, the input impedance of a pair of 3-500Zs appears to be
rather different to a pair of 572B (which is about 120 ohms)!

Please, does anyone have details of a suitable input circuit for the
SB200 for 160m (preferably one they have used themselves, but all
offers are gratefully accepted)?   If so, could they email me direct?

Many thanks!

Vy 73

Steve Ireland, VK6VZ