[Hackrf-dev] Still hoping for PTT

[Dominic Spill]

I'm not certain, because I don't want to break portapack or other add on
boards, but it may be possible for us to toggle a GPIO pin on one of the
headers when we switch to TX mode, if that would help?

Dominic

On 20 June 2018 at 17:55, Gavin Jacobs <apriljunkbox at hotmail.com> wrote:

> Chuck,
> I have used the bias-t voltage on the hackrf to power an upconverter but
> it isn’t easy to turn it on and off. The only method I know is to use
> hackrf-transfer - but that doesn’t work when switching to/from rx & tx.
>
> Meanwhile I have brought the tx LED signal out from P5, and it is
> switching the power amp on and off just fine.
>
> Jake
>
> On Jun 19, 2018, at 7:02 PM, Chuck McManis <chuck.mcmanis at gmail.com>
> wrote:
>
> FWIW the idiomatic way to achieve this as far as I can tell is to send a
> bias-T signal on the RF cable, basically its a DC offset on the cable which
> the PA picks up and switches on. This lets you have short cables between
> the PA and the antenna and its only one line to hook up (the antenna coax)
>
> On Tue, Jun 19, 2018 at 5:04 PM Gavin Jacobs <apriljunkbox at hotmail.com>
> wrote:
>
>> Bernie
>> That’s a great idea! I looked on the hackrf schematic and the signal for
>> the TX LED is brought out to a (DNP) header - all I have todo is bring that
>> signal out to my PTT circuit. Thanks for the suggestion!
>>
>> Jake
>>
>>
>> On Jun 15, 2018, at 5:32 AM, Bernard Kobier <bernardkobier at tpg.com.au>
>> wrote:
>>
>> I admit I have not tried this but what about using the TX LED to drive an
>> optocoupler to switch the amp?
>>
>> Bernie
>>
>>
>>
>> On 11 Jun 2018, at 00:53, CJ Hicks <cjhicks at dadelus-engineering.com>
>> wrote:
>>
>> Why not leave your exciter on and only PTT your power amplifier (PA)?  Or
>> use an RF to shunt your exciter signal into a dummy load.  Just a couple of
>> random thoughts.
>>
>> CJH
>>
>> *From:* HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com
>> <hackrf-dev-bounces at greatscottgadgets.com>] *On Behalf Of *Gavin Jacobs
>> *Sent:* Saturday, June 09, 2018 5:57 PM
>> *To:* hackrf-dev at greatscottgadgets.com
>> *Subject:* [Hackrf-dev] Still hoping for PTT
>>
>> Has there been any progress on implementing digital i/o from/to the
>> hackrf One. I'm hoping that someday the hackrf can supply a PTT signal to
>> an external amplifier.
>>
>> Jake
>>
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>>
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>
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