Re: Elecraft KX3 Owner's Manual now available (*preliminary*)

Posted by Joe Subich, W4TV-4 on Mar 05, 2012; 9:47pm
URL: http://elecraft.85.s1.nabble.com/Elecraft-KX3-Owner-s-Manual-now-available-preliminary-tp7343177p7346508.html


Lance,

> However, my discussions recently have not been involving those big
> amps at all...rather my current application is to use the KX3 on
> overseas 6m EME Dxpeditions in conjunction with the M2 6M-1000 12
> pound 6m amplifier. I greatly appreciate all the guidance, and I
> will plan to build up some sort of arrangement to key the KX3 via the
> PTT line out of the MIC connector.

Since your concern is really for switching the amplifier and possibly
an LNA, you may be able to "split the baby".  Consider using the KX3
serial cable and a USB to serial converter.  That way you can use RTS
to switch the amplifier (split out a simple single transistor driver
for the amplifier) and allow the WSJT software to delay audio by +/-
200 ms with the KX3 in VOX.

You could even build the transistor driver into the EME amp (PTT on
 > +3V) so the only "extra" item needed would be a simple splitter cable
to connect between the USB converter and KX3SER cable.

The same solution would be applicable to *any* transceiver with a TTL
or RS-232 control interface and old laptops with a traditional serial
port.  Allow the transceiver to switch based on "data VOX" and have
the software provide "advance PTT".  If memory serves, the specs call
for JT-65 to assert PTT on the minute with tones starting one second
past the minute which by its very nature provides a 1 second "advance
PTT".

73,

    ... Joe, W4TV


On 3/5/2012 4:16 PM, W7GJ, Lance wrote:

> Hi Jim,
>
> TNX for your suggestions on the Harris amps on my website.  I agree that they should
> have some good switching on them, and have been suggesting that people use good
> coaxial relays, preferably those with an extra set of protection contats, so the amp
> is not turned on until the coax relays has switched.  They are great amps, though,
> and have fantastic protection circuitry built into them, so they are really hard to
> damage ;-) And it is nice to be able to get around a kw on 6m with only 10w of drive!
>
> However, my discussions recently have not been involving those big amps at
> all...rather my current application is to use the KX3 on overseas 6m EME Dxpeditions
> in conjunction with the M2 6M-1000 12 pound 6m amplifier.  I greatly appreciate all
> the guidance, and I will plan to build up some sort of arrangement to key the KX3 via
> the PTT line out of the MIC connector.
>
> VY 73, Lance
>
>
> On 3/5/2012 8:29 PM, Jim Brown-10 [via Elecraft] wrote:
>> On 3/5/2012 11:09 AM, W7GJ, Lance wrote:
>>   >  However, my solid state 6M-1000 amplifier has a little mechanical antenna relay in
>>   >  it, and the last thing I can afford to do is to hot switch that amp on a 6m EME
>>   >  DXpedition and blow up the transistors and/or the little transfer relay inside it.
>>
>> I understand, and like many others, greatly appreciate your initiative
>> to recycle those high quality ch 2 power amps for 6M. BUT -- designing
>> and building some sort of bulletproof T/R antenna switching ought to be
>> part of that conversion. It doesn't take much to rig a suitable vacuum
>> relay like the Jennings, Kilovac, or Gigavac, and the Ten Tec schematics
>> for the Titan 425, which are on my website, illustrate an easy way to
>> sense that the relay has positively switched. They did it in the late
>> 70s with discrete small signal NPN and PNP transistors, and it still
>> works just fine 35 years later. BTW -- Alpha uses Gigavac relays in
>> their current production, and they're not expensive. They will sell
>> small quantities directly to hams at about $80 each, and I've heard of
>> at least respected ham vendor who beats that price by something like 20%.
>>
>> While it's great to see more features built into Elecraft rigs, we must
>> realize that they are not free (at a minimum there is engineering time
>> to do the programming and document it), some can be costly or
>> impractical, depending on the hardware, and when they are costly, it is
>> not reasonable to burden all KX3 owners with things that can (and
>> should) be done outside the radio.
>>
>> 73, Jim K9YC
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