--- In ham_amplifiers@..., R L Measures <r@...> wrote:
? As I understand it, Trio-Kenwood has stopped selling
bandswitches
for the TL-922. The stock TL-922 uses VHF parasitic suppressors
with
a Q of c. 5.5 @ 100MHz. Since the the TL-922's original
suppressors
with a pair of fresh 3-500Zs can produce intermittent oscillations
c.
120MHz which can arc, melt & even evaporate the 10m and 15m L
contacts on the bandswitch, owners can avoid the problem by
either
switching to lower-Q VHF suppressors to lower VHF-gain, or by
using
worn-out 3-500Zs to do the same.
- end
### Owner's can avoid the parasitic problem altogether by simply
removing the 2 x rf chokes from the gid pins... plus the 6 x 200 pf
caps from the same grid pins..... and then directly ground the 6 x
grid pins with wide strap. Then the stock suppressor's will work
just fine.
## By semi-floating the grids you are just asking for parasitic
trbl.
Later... Jim VE7RF
R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org
