XVRT sequencing

[Evert Bakker (PA2KW)]

Hello to all,

I'm at the stage of inserting my K2 into the VHF setup. I've been using a
Ten-Tec Paragon for the last 18 years as the IF stage for my 2 mtr station.
The Ten-Tec has two connectors at the back (RCA?) with the function "TX-OUT"
and "TX-EN". In normal standalone operation a bridge is plugged in. When
using amps, and in my case a XVRT - PA - HF Relay, the TX-OUT is a request
for transmit (initiated by the internal combination of the PTT, key(er) or
tune button. I use this signal in my sequencer to sequentially switch the
final HF-relay - switch the PA in TX mode - and switch the XVRT in TX mode
after a defined time delay. When this procedure is accomplished I give an
enable (TX-EN) signal to the Ten-Tec to switch over in TX mode. This
procedure enables absolute power-free switching. (I never blew any relays,
amps and preamps in the last 18 years of intensive use).
To make use of my sequencer again, I was looking for this function in the
K2. Unfortunately I could not find this closed loop procedure.

Of course I can short circuit the "XVRT-OUT" plug (after a 10 dB pad) from
the K60XV module to prevent RF injection into my XVRT. I just don't like
this type of solution.

I saw an RX 8V signal on the DB9 / RS232 connector (included in the KPA100
option, which I bought but not installed yet), but this signal is not the
one I can use as described in my above story.

Is there anyone out there who made some changes in the K2 which gives
similar sequence procedures as with the Ten-Tec?

Thanks in advance.

Evert, PA2KW
K2: #4836




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[Don Wilhelm-3]

Evert,

You are correct, the K2 is always 'full QSK' operation on CW, and a key
closure is what begins the cycle.  The K2 amplifier keying circuit shown on
the Elecraft website will provide an output that essentially says "RF output
will follow in about 15 ms."

Take a look on my website http://w3fpr.qrpradio.com for the 'CW PTT' - it
will accomplish the function you want.  It's operqtion is to interrupt the
keying until a signal is received on the added PTT input.  How your
sequencer chain is kicked off may be another problem, that part of the
implementation is up to the user - if you use a footswitch or similar, then
the answer is obvious, but if it is started by just hitting the paddles,
there will be no source for the sequencer start signal.

73,
Don W3FPR

> -----Original Message-----
>
> Hello to all,
>
> I'm at the stage of inserting my K2 into the VHF setup. I've been using a
> Ten-Tec Paragon for the last 18 years as the IF stage for my 2
> mtr station.
> The Ten-Tec has two connectors at the back (RCA?) with the
> function "TX-OUT"
> and "TX-EN". In normal standalone operation a bridge is plugged in. When
> using amps, and in my case a XVRT - PA - HF Relay, the TX-OUT is a request
> for transmit (initiated by the internal combination of the PTT, key(er) or
> tune button. I use this signal in my sequencer to sequentially switch the
> final HF-relay - switch the PA in TX mode - and switch the XVRT in TX mode
> after a defined time delay. When this procedure is accomplished I give an
> enable (TX-EN) signal to the Ten-Tec to switch over in TX mode. This
> procedure enables absolute power-free switching. (I never blew any relays,
> amps and preamps in the last 18 years of intensive use).
> To make use of my sequencer again, I was looking for this function in the
> K2. Unfortunately I could not find this closed loop procedure.
>
> Of course I can short circuit the "XVRT-OUT" plug (after a 10 dB pad) from
> the K60XV module to prevent RF injection into my XVRT. I just don't like
> this type of solution.
>
> I saw an RX 8V signal on the DB9 / RS232 connector (included in the KPA100
> option, which I bought but not installed yet), but this signal is not the
> one I can use as described in my above story.
>
> Is there anyone out there who made some changes in the K2 which gives
> similar sequence procedures as with the Ten-Tec?
>
>

--
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[Evert Bakker (PA2KW)]

Hello Don,

Thanks for your information. I understand that what I want is not available
from "stock". In the meantime I've been reading some stuff on several url's
about this subject.
I do have a rather complicated setup here for my VHF station. I'm running
real FSK when active on CW and HSCW / FSK441 for meteorscatter or moonbounce
because RFI/TVI problem when running high power on 144Mc. I'm living in a
rather populated area and would limit my self or hinder my neighbours. Both
I don't like, hi. My transverter has got a DDS running at 116 Mc (a bit of
an overkill but clean signal and FSK capability). The FSK voltage is
generated by a audio(Hz)-voltage converter. I asked Elecraft if they would
think about FSK capabilities in the future. This would enhance the K2 for
specialized usage as an IF stage in transvertor concepts. Unfortunately they
won't. The K2 makes use of a PLL circuit which makes FSK a lot more
complicated while keeping signal performance at high standards.    
I've been looking to bend the pins (dot/PTT and dash) from the MCU and bring
them to a connector (opto-isolated). This could work but leaves me still
with hot switching when using the Tune button.
I decided to leave the K2 as is and will design my own interface to tackle
the needs (starting in the autumn and keep my Ten-Tec running for the
moment).
Anyway, when finished I'll inform the reflector in case someone is
interested.

I wish you all a nice week end.

Evert, PA2KW
K2, #4836


-----Original Message-----
From: W3FPR - Don Wilhelm [mailto:[hidden email]]
Sent: 09 July 2005 03:55
To: [hidden email]; Elecraft e-mail reflector
Subject: RE: [Elecraft] XVRT sequencing

Evert,

You are correct, the K2 is always 'full QSK' operation on CW, and a key
closure is what begins the cycle.  The K2 amplifier keying circuit shown on
the Elecraft website will provide an output that essentially says "RF output
will follow in about 15 ms."

Take a look on my website http://w3fpr.qrpradio.com for the 'CW PTT' - it
will accomplish the function you want.  It's operqtion is to interrupt the
keying until a signal is received on the added PTT input.  How your
sequencer chain is kicked off may be another problem, that part of the
implementation is up to the user - if you use a footswitch or similar, then
the answer is obvious, but if it is started by just hitting the paddles,
there will be no source for the sequencer start signal.

73,
Don W3FPR

> -----Original Message-----
>
> Hello to all,
>
> I'm at the stage of inserting my K2 into the VHF setup. I've been using a
> Ten-Tec Paragon for the last 18 years as the IF stage for my 2
> mtr station.
> The Ten-Tec has two connectors at the back (RCA?) with the
> function "TX-OUT"
> and "TX-EN". In normal standalone operation a bridge is plugged in. When
> using amps, and in my case a XVRT - PA - HF Relay, the TX-OUT is a request
> for transmit (initiated by the internal combination of the PTT, key(er) or
> tune button. I use this signal in my sequencer to sequentially switch the
> final HF-relay - switch the PA in TX mode - and switch the XVRT in TX mode
> after a defined time delay. When this procedure is accomplished I give an
> enable (TX-EN) signal to the Ten-Tec to switch over in TX mode. This
> procedure enables absolute power-free switching. (I never blew any relays,
> amps and preamps in the last 18 years of intensive use).
> To make use of my sequencer again, I was looking for this function in the
> K2. Unfortunately I could not find this closed loop procedure.
>
> Of course I can short circuit the "XVRT-OUT" plug (after a 10 dB pad) from
> the K60XV module to prevent RF injection into my XVRT. I just don't like
> this type of solution.
>
> I saw an RX 8V signal on the DB9 / RS232 connector (included in the KPA100
> option, which I bought but not installed yet), but this signal is not the
> one I can use as described in my above story.
>
> Is there anyone out there who made some changes in the K2 which gives
> similar sequence procedures as with the Ten-Tec?
>
>

--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.323 / Virus Database: 267.8.10/43 - Release Date: 7/6/2005

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