To touch on the point, unless the Thunderbolt has been modified, there is no
switching or relays inside the amp. The input connector goes direct to the
input selector switch which then goes to the input network and then the
grids of the 4-400 tubes. The output of the Pi network is connected direct
to the output coax connector. At the right rear of the amp is a 4 pin
connector. The pins are ground, operate bias, standby bias and grid. To
switch from standby to operate the correct bias voltage much be switched to
the grid terminal. The VR regulators are for the screen voltage and the
bias voltage.
To configure the amp for QSK, one will need to provide a means to switch RF
at the input and output of the amp and a means to simultaneously switch the
bias from standby to operate. I am not aware of any commercial product that
will accomplish this task. Thus expect to "roll your own" switching system.
Operating in Class AB2 mode, the input circuit is a tuned input and thus the
drive power for rated output is in the order of 2 watts. In the LINEAR mode
the input is swamped by a big resistor and one can expect required drive to
be about 30 watts or so.
The Johnson Thunderbolt was designed and sold in the 1960's and was used for
SSB and AM. I don't recall we even knew what QSK was during that time
period. Later Johnson came out with an "electronic" T/R switch. These were
found to be mostly monster TVI generators as the switching tube was driven
into a gross area of non linearity.
Although this amp is a very well built amp and will run for days in a
key-down mode, they weight in at some 135 lbs. The HV transformer in a full
wave CT configuration, the swinging filter choke and the low voltage
transformer and filter choke adds some serious iron to this amp. Power
output is in the area of 600 to 750 watts. Remember, this amp was designed
when the "legal limit" was 1 KW DC input. The meter scale is so calibrated
as well.
I just completed a re-furbish job on one of these. If they are used as
designed, they will produce some of the cleanest RF of any amp on the market
today. They are great and one won't need to worry about the desk moving
around when sending aggressive CW.
73
Bob, K4TAX
----- Original Message -----
From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Saturday, December 07, 2013 2:10 AM
Subject: Re: [TenTec] 318 and qsk-5
GM Mike,
I think I will pass on this one.
This is not going to be a PLUG'n'Play solution.
Bob seems to know them.
I 'remember' seeing them when I was a kid, but I left the states soon
after
that and never saw one again.
In general, if you want to run QSK with a NON-QSK Amp, you will need the
QSK5.
The Model 318 has no way to speed up switching inside the amplifier.
It just slows down the switching when returning to RX mode, to PREVENT the
amp from "trying" to follow the QSK switching.
In other words, the Model 318 enables "Clean Semi-BK", but with a caveat.
The amp's relay can't be too big and clunky. If so, it won't be happy
with
the 15mS pre-dit time which is a fixed value coming from the Orion. For
the
Eagle, it's 17mS.
TEN-TEC, PLEASE INCREASE THIS TO "20Ms" or better yet, "22mS", AND THEN IT
WILL WORK WITH JUST ABOUT ANYTHING!
NOTE: the specs on most open frame relays are something like 15 to 20 mS
switching plus 1 to 2 mS settling time, depending on make and model.
The QSK-5 actually does enable QSK switching, at least with most amps, but
in the case of the Thunderbolt, you will need to add additional hardware.
By the time you do all that, it may have been just as easy to pick up a
second, used amp.
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Michael
Tortorella
Sent: Saturday, December 07, 2013 12:37 AM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] 318 and qsk-5
Hi Rick, sorry, I forgot to include that the rigs are Corsair II and
Johnson
Courier or Thunderbolt. Was hoping to use the amp with QSK.
73
Mike
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Rick -
DJ0IP / NJ0IP
Sent: Friday, December 06, 2013 4:23 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] 318 and qsk-5
Mike, these are two totally different animals.
The QSK-5 speeds up the amp switching, while the 318 slows it down.
Both solutions can work, but it also depends a bit on the amp and how fast
its relay switches.
What rig and amp are you trying to mate.
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Michael
Tortorella
Sent: Friday, December 06, 2013 6:32 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: [TenTec] 318 and qsk-5
Tentec friends, I am looking for help comparing the TenTec 318 with the
Ameritron QSK-5. Has anyone used either/both of these who could offer
some
insights?
Thanks and 73
Mike W2IY
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