[Amps] Pi-L Tank on TenTec Titan 425

[Rich Hallman - N7TR]

I have seen this as well with the two Titan 425's I have.   Seeing a fix
here would be great!  I love the amp....but would love to see the tuning
more in the "mid-range" of the tune sweep.

Thanks...
Rich

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
On Behalf Of Gary Myers
Sent: Thursday, December 21, 2006 8:07 AM
To: amps at contesting.com
Subject: Re: [Amps] Pi-L Tank on TenTec Titan 425

Help!

 I have a nice Titan - works great for the most part even with a
 20 year old tube... however on 10 meters the "peak" on the tune
 capacitor is right at the minimum capacitance point above about
 28.1 Mhz. Is there anything I can do, simply, to raise this 
just
 enough to know I am tuned properly (i.e. requiring LESS
 capacitance)?

 I contacted TT service - they are a great bunch of people for
 the most part... they said

 I spoke to the RF design engineer. If the coil is expanded on 
10
 meters in
 order to use more tune capacitance then the tuning will change
 on 15 meters.
 If the tuning is changed on 15 meters then the plate choke 
might
 be damaged.
 The suck out frequency for the plate choke is near the 15 meter
 band. As
 long as the tune cap will resonate there is no problem.

 My response was it does NOT resonate now - it is obvious it
 needs less capacitance to do so... and that I can't imagine it
 is THAT close and critical... finally something most be off to
 begin with for it not to work as spec'd in their manual 
(setting
 in manual is 5% of capacitance). Of course I could change the
 series cap, 25p to maybe a 20 but finding one might be 
difficult
 and getting it in more so... I could also parallel another high
 value cap with the 25 but again space dictates this to be
 difficult...I would love to know if I can spread (or compress?)
 the 10 meter section of the coil and accomplish what I need. 
The
 SWR is around 1.2:1 - 1.3:1.

 thanks for any help.

 Gary
 K9RX



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