thank you all for the info on running rtty with the titan 425. hope to print
you all some time.
73's tnx,
steve w1dxh
In a message dated 1/18/2008 12:27:27 P.M. Eastern Standard Time,
sales@tentec.com writes:
Bob -- I think you're quoting the specifications from the Titan II or
Titan III.
The Titan 425 is rated at 1000 watts continuous -- no time limit.
Running RTTY with that amplifier at 1500 watts in usual digital mode
duty cycle will not present a problem. The maximum power output for CW
and SSB was well over 2000 watts -- it was designed with lots of
headroom. The pair of 3CX800A's is rated 120 mA maximum grid current;
1500 watts out into a good load should run the amp in the 30-40 mA
range, typically.
There were 3 Amateur Radio versions of the Titan 425. The easy way to
tell them apart: the first had a dark case like the original Corsair,
mid-1980's. The second was a grey case, Corsair II-style knobs and says
TITAN 425 on the front panel. Serial numbered up to 425-01000. Roughly
1986 to 1989. Third version has the rubberized knobs like the modern HF
rigs, says TITAN on the front, serial numbers after 425-01000 and then
date encoded serial numbers which we started using in 1989. There
technically was a fourth version -- the "Titan Gold" series, which were
the last 50 units built of the Titan. They had a gold plate on the
front and a gold plastic logo. They are the same as the third version
except they were the very last ones we sold when we announced we were
cutting it off and doing one final production run in 1996-97.
For the technical differences between the amps, I'd refer to the service
department. I don't know them off the top of my head.
There was also a military version of the Titan called the Titan 425D.
Different power supply -- rack mount unit. More broadbanded coverage
than the ham bands version, the front panel bandswitch labeling is not
15-20-40 etc. for the ham bands, but was labeled with frequency
information like 3.3-5.7 MHz, etc. Required less drive power than the
425. Front panel, rear panel, and power supply also say Titan 425D.
Interestingly enough, 15 years or so out of production not many of these
have turned up for ham radio use. One can only wonder where they all
are now.
I bought a used 1989 vintage second version Titan 425 in 2001 and it has
been run up to 20 contests a year since that time. Great amp.
73
Scott Robbins
W4PA
Bob McGraw - K4TAX wrote:
> For RTTY it is rated 1000 watts output for 10 minutes of transmit time
with
> a 50% duty cycle. i.e. 10 minutes transmit, followed by 10 minutes of
> receive. Follow the TUNE UP procedure in the manual and do not over drive
> the amp. Pay very close attention to Screen current and grid current. Be
> sure the load/antenna is near 50 ohms i.e. SWR <1.5:1 before starting to
> tune the amp. Start with 10 watts of drive from the exciter.
>
> While it is well protected, overdrive can make for expensive and sudden
> tube replacement needs.
>
> And, if you don't have a manual, order one from Tentec.
>
> 73
> Bob, K4TAX
>
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