[Amps] TL-922 question

[R L Measures]

On Aug 29, 2006, at 12:06 PM, Tom W8JI wrote:

>
>>> From the responses, I see two possibilities.
>>
>> 1. Replacing the blocking cap may have necessitated
>> increasing the
>> padder caps on 80 and 160.  It seems like all the load
>> positions are a
>> bit less than the manual would indicate.  The other bands
>> are still in
>> range.
>
> You can go all the way down to a few hundered pF on the
> blocker and it will make very little difference in tuning.
> It is at a few thousand ohm impedance point.

Indeed, Tom.
>
> If the blocker was so bad as to affect 160 or 80
> performance, it would be smoking.

Bad blockers are shorted because the dielectric punches through.
>
>> 2. The 80 meter padder cap, which is also used on 160, is
>> actually 2
>> ganged sections of the 5 section Load variable cap.  It is
>> possible that
>> this cap has become disconnected somewhere in the path
>> from the
>> bandswitch to ground.  The 160 padders are discrete
>> components
>
> The problem is the 922 when stock barely makes the lower end
> of 160 and 80. Compounding that problem more C is required
> as drive is reduced.
>
> There is an inherent shortfall in network range on both 160
> and 80.

In my TL-922, there is enough C to reach 3.5MHz and 1.8MHz when the  
amplifier is driven with 120w.
...
R L MEASURES, AG6K. 805-386-3734
r at somis.org