I don't think the big multi-multis care about QSK, anyway. The ones I
know of run semi. As for Germany alas, no. I'd love to have a go, though! :)
PIN diode switches are, in the end, probably not suited to multi-multi
stations, anyway as they won't tolerate big mismatches. I have the
Ameritron QSK5 internal switches on both my amps and I've blown the
receive fuses in them a couple of times because I selected the wrong
antenna in the heat of battle. I've never been in enough RF for them to
cause problems, though I'm sure it can happen. Outside of that, I've
found them quite reliable.
Rick, did you ever receive my reply about Oklahoma?
Kim N5OP
On 3/17/2014 3:19 PM, Rick - DJ0IP / NJ0IP wrote:
Kim, apparently you have never operated a multi-multi station with 6
stations running 1.5kW at the same time, within a few hundred yards of each
other.
And you must not have had Pin Diode switching in Germany because the RF
power in the air at night is significant.
It slightly forward biases the diodes and they cause intermodulation
distortion.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Kim Elmore
Sent: Monday, March 17, 2014 8:09 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] QSK or not?
I was thinking more along lines for amplifier switching. I have PIN diode
switches in both of my amps. There are a few AM BC stations within a few
miles of me - one is a 50 kW blowtorch and the others are 1 to 5 kW. I've
never heard any overload problems attributable to the PIN diode switches.
There's only one ham nearby (about 2.5 mi away) who can run 1.5 kW and I've
never heard anything attributable to the switches then, either. The "on"
bias for the rx diodes runs about 100 mA or so and the source voltage is 12
V.
I can't claim that they can't generate problems (kW field day ops might well
create some as might big multi-multi stations) but I can claim that I've
never encountered any.
Kim N5OP
"People that make music together cannot be enemies, at least as long as the
music lasts." -- Paul Hindemith
On Mar 17, 2014, at 13:51, Carl Moreschi <n4py3@earthlink.net> wrote:
Because relays don't cause receive overload problems when very strong
signals saturate the pin diodes.
Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com
On 3/17/2014 2:14 PM, Kim Elmore wrote:
Why use relays when we have PIN diodes?
Kim N5OP
"People that make music together cannot be enemies, at least as long
as the music lasts." -- Paul Hindemith
On Mar 17, 2014, at 11:43, "Rick - DJ0IP / NJ0IP"<Rick@DJ0IP.de> wrote:
Different relays have different life cycles.
AND, keep in mind that this spec was specified for a relay when
switching between two STABLE STATES.
If you run full QSK with the relay following the keying, sometimes
the relay is in transition when it gets a command to go the other
way. It must overcome inertia and change directions. THIS IS
ADDITIONAL WEAR AND TEAR on the relay.
THIS type of operation is not considered in the specs.
Also, when Phil wrote that paper on QSK, he was referring to the
open-frame relay used in ALL Ameritron amplifiers.
I guarantee you that this relay will NEVER WEAR OUT when trying to
follow QSK keying. . .
BECAUSE IT WILL BURN UP LONG BEFORE IT WEARS OUT! (hi)
UNFORTUNATELY AMERITRON IS HOPELESSLY BEHIND THE POWER CURVE WITH
THEIR DEPLOYMENT OF THIS RELAY!
I would remind people at this point to keep in mind that there are 3
VERY different kinds of relays used for T/R switching in the linear
amplifiers that we use. The differences are HUGE!
You'll find pictures and short description of these on my web site,
Here:
http://www.dj0ip.de/ten-tec-stuff/misc-stuff/linear-amp-relays/
ALTHOUGH AMERITRON publishes a switching time of 15mS for its relays
and [falsely] advertises them as "fast- nearly as fast as some QSK
relays"
[puke], these relays are DIRT SLOW.
In reality they switch with 17 to 20mS delay, depending on the
situation.
*** AS MEASURED LAST WEEK BY BOB, K4TAX. ***
Phil is absolutely right!
(sorry Gary)
NEVER-THE-LESS, there is still a way to have near QSK with the slow
Ameritron Amps (without the expensive QSK-5) and still hear in
between words; just not in between dit, dahs, or characters. It's
just a matter of proper time sequencing. I've been doing it with these
amps for 30+ years.
As long as you can hear between words, there is no tangible
disadvantage between QSK that can hear between dits. OK, perhaps
you notice someone is transmitting when you are... 1/10 second
later than with true full QSK. If you are willing to accept this, you
can avoid burning the relay.
In order to do this, you will need an external keyer that has
adjustable time sequencing. There are a few of these on the market
(i.e., WINKEY, MFJ-495, etc.) AND several rig interface boxes such
as the "MicroHam MicroKeyer II" have adjustable delay (time
sequencing) parameters. If you understand the timing, it's a piece
of cake to set this up. With devices like that, you may use any keyer -
EXCEPT the rig's own built-in keyer.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of
GARY HUBER
Sent: Monday, March 17, 2014 4:40 PM
To: TenTec Reflector
Subject: [TenTec] QSK or not?
I operate QSK and have the past thirty years using TenTec equipment.
One reason given by others for not running QSK is that the relays
wear out sooner in the transceiver and amplifier.
from
http://www.ad5x.com/images/Presentations/QSKals500als600RevA.pdf
How Long will the Relays Last?
What kind of life can you expect from the relays? The relay life is
specified at 100 million operations minimum at 36,000
operations/hour. The service life increases as the operations/hour
decreases. So let's use the standard PARIS text that is used for
determining code speed.
PARIS has 10 dits and 4 dahs = 14 relay operations/minute at 1 WPM.
Assuming an average of 25WPM code speed, you would have 360 relay
operations per minute. So, 100 million operations = 4630 hours. Now
you normally operate 50% transmitting and 50% receiving during a
QSO, so your relay operating time should double to 9260 hours. There
are 8760 hours/year, which means you could operate 1.057 years at 25
WPM before the relays exceeded their lifetime spec - IF you operate
24 hours/day! But when you operate, you are probably listening more
like 75% of the time and in a QSO 25% of the time. So this says that
your relay operating life will be over 4- years if you operate 24
hours/day. So what do you normally average in operating time/day? I
bet it is not more than about an hour/day. But let's say you average
4- hours/day of operation (i.e. you are not married and have no
kids, you don't shop or eat or sleep much, and you don't hold a
full-time job). So the relay life will extend to about
25 years! The bottom line - Don't worry about wearing out the relays
anytime soon.
73 ES DX,
Gary - AB9M -...-.-
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