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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