[600MRG] U3S with T/R relay

[John Molnar]

I'm not sure how a classic sequencer (external PTT starts RX->TX sequence)
works here.

If U3S asserts it's 'PTT' +5v signal EXACTLY with appearance of the RF, a
sequencer does nothing
for you.  The TX is going to hot switch at the T/R relay.

Hans needs to add code to the WSPR mode to assert a PTT signal at the 2
min. TX sequence. in advance of the RF.

This is exactly what WSPR on a computer does with RTS/DTS in advance of the
tone.

John XKA



On Tue, Nov 1, 2016 at 3:14 PM, K2ORS <k2ors at verizon.net> wrote:

> There are better and cheaper sequencers out there:
> http://www.advancedreceiver.com/page20.html
>
> http://www.w6pql.com/relay_sequencer.htm
>
> I've used both and can vouch for them.
>
> 73 Warren K2ORS
>
>
>
> ----- Original Message ----- From: "Edward R Cole" <kl7uw at acsalaska.net>
> To: "Steve Flood" <kk7uv at bresnan.net>; <600mrg at w7ekb.com>
> Sent: Tuesday, November 01, 2016 11:10 AM
> Subject: Re: [600MRG] U3S with T/R relay
>
>
> Steve,
>>
>> It looks like you want a sequencer:
>> http://www.downeastmicrowave.com/category-s/1833.htm
>>
>> model TRS ...$120 assembled
>> or TRSCK kit ... $85
>> or TRSK ... $35 pcb kit w/o hdwr or enclosure
>>
>> 73, Ed - KL7UW
>>
>> At 02:12 AM 11/1/2016, Steve Flood wrote:
>>
>>> I plan to use an Ultimate 3S for WSPR operation.  I will be using it to
>>> drive an external Class D amplifier (using the square-wave output from
>>> the
>>> U3S synth chip with its own PA disabled).
>>>
>>>
>>>
>>> I am having trouble figuring out how to activate the output T/R antenna
>>> relay prior to RF transmission.  Likewise I need to key the driver stage
>>> of
>>> the external amp.  This all needs to be automated for unattended WSPR
>>> TX/RX
>>> sessions.
>>>
>>>
>>>
>>> I was hoping to use the +5v "KEY" output from the U3S to activate the
>>> relay
>>> and driver, but Hans tells me that it is essentially simultaneous to the
>>> RF
>>> output.  I am trying to avoid hot-switching the T/R antenna relay or
>>> causing
>>> a load fault shutdown.
>>>
>>>
>>>
>>> Any ideas?   How have others used the U3S with a T/R antenna relay?
>>>
>>>
>>>
>>> Thanks,
>>>
>>> Steve KK7UV/WH2XNV
>>>
>>>
>>>
>>>
>>>
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>>
>> 73, Ed - KL7UW
>> http://www.kl7uw.com
>>     "Kits made by KL7UW"
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