Discussion:
[Hackrf-dev] Still hoping for PTT
Gavin Jacobs
2018-06-09 21:57:21 UTC
Permalink
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
CJ Hicks
2018-06-10 14:53:52 UTC
Permalink
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-***@greatscottgadgets.com] On Behalf
Of Gavin Jacobs
Sent: Saturday, June 09, 2018 5:57 PM
To: hackrf-***@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
Gavin Jacobs
2018-06-20 00:04:50 UTC
Permalink
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 <***@tpg.com.au<mailto:***@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 <***@dadelus-engineering.com<mailto:***@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-***@greatscottgadgets.com] On Behalf Of Gavin Jacobs
Sent: Saturday, June 09, 2018 5:57 PM
To: hackrf-***@greatscottgadgets.com<mailto:hackrf-***@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

_______________________________________________
HackRF-dev mailing list
HackRF-***@greatscottgadgets.com<mailto:HackRF-***@greatscottgadgets.com>
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
Chuck McManis
2018-06-20 01:01:51 UTC
Permalink
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 <***@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 <***@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 <***@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-***@greatscottgadgets.com
> <hackrf-dev-***@greatscottgadgets.com>] *On Behalf Of *Gavin Jacobs
> *Sent:* Saturday, June 09, 2018 5:57 PM
> *To:* hackrf-***@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
>
> _______________________________________________
> HackRF-dev mailing list
> HackRF-***@greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>
>
> _______________________________________________
> HackRF-dev mailing list
> HackRF-***@greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>
Gavin Jacobs
2018-06-20 23:55:05 UTC
Permalink
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 <***@gmail.com<mailto:***@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 <***@hotmail.com<mailto:***@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 <***@tpg.com.au<mailto:***@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 <***@dadelus-engineering.com<mailto:***@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-***@greatscottgadgets.com] On Behalf Of Gavin Jacobs
Sent: Saturday, June 09, 2018 5:57 PM
To: hackrf-***@greatscottgadgets.com<mailto:hackrf-***@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

_______________________________________________
HackRF-dev mailing list
HackRF-***@greatscottgadgets.com<mailto:HackRF-***@greatscottgadgets.com>
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

_______________________________________________
HackRF-dev mailing list
HackRF-***@greatscottgadgets.com<mailto:HackRF-***@greatscottgadgets.com>
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
Dominic Spill
2018-06-26 16:58:53 UTC
Permalink
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 <***@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 <***@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 <***@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 <***@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 <***@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-***@greatscottgadgets.com
>> <hackrf-dev-***@greatscottgadgets.com>] *On Behalf Of *Gavin Jacobs
>> *Sent:* Saturday, June 09, 2018 5:57 PM
>> *To:* hackrf-***@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
>>
>> _______________________________________________
>> HackRF-dev mailing list
>> HackRF-***@greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>>
>> _______________________________________________
>> HackRF-dev mailing list
>> HackRF-***@greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>
> _______________________________________________
> HackRF-dev mailing list
> HackRF-***@greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>
>
Gavin Jacobs
2018-06-26 18:18:37 UTC
Permalink
Dominic
Thanks for that offer/suggestion, but it’s already done! I found the TX mode signal that drives the TX LED, and it was already brought out to P5. So All I had to do was solder some ribbon cable to P5 socket (which is not populated). I have it connected to my power amp such that it energizes whenever the Hackrf is in transmit mode.

Jake


On Jun 26, 2018, at 10:59 AM, Dominic Spill <***@gmail.com<mailto:***@gmail.com>> wrote:

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 <***@hotmail.com<mailto:***@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 <***@gmail.com<mailto:***@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 <***@hotmail.com<mailto:***@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 <***@tpg.com.au<mailto:***@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 <***@dadelus-engineering.com<mailto:***@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-***@greatscottgadgets.com] On Behalf Of Gavin Jacobs
Sent: Saturday, June 09, 2018 5:57 PM
To: hackrf-***@greatscottgadgets.com<mailto:hackrf-***@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

_______________________________________________
HackRF-dev mailing list
HackRF-***@greatscottgadgets.com<mailto:HackRF-***@greatscottgadgets.com>
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

_______________________________________________
HackRF-dev mailing list
HackRF-***@greatscottgadgets.com<mailto:HackRF-***@greatscottgadgets.com>
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

_______________________________________________
HackRF-dev mailing list
HackRF-***@greatscottgadgets.com<mailto:HackRF-***@greatscottgadgets.com>
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
Chuck McManis
2018-06-26 22:51:56 UTC
Permalink
Or to put it differently, :-) If the HackRF would enable the ANT bias when
it was transmitting then it would "just work" as they say.

On Tue, Jun 26, 2018 at 11:18 AM Gavin Jacobs <***@hotmail.com>
wrote:

> Dominic
> Thanks for that offer/suggestion, but it’s already done! I found the TX
> mode signal that drives the TX LED, and it was already brought out to P5.
> So All I had to do was solder some ribbon cable to P5 socket (which is not
> populated). I have it connected to my power amp such that it energizes
> whenever the Hackrf is in transmit mode.
>
> Jake
>
>
> On Jun 26, 2018, at 10:59 AM, Dominic Spill <***@gmail.com> wrote:
>
> 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 <***@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 <***@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 <***@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 <***@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 <***@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-***@greatscottgadgets.com
>>> <hackrf-dev-***@greatscottgadgets.com>] *On Behalf Of *Gavin Jacobs
>>> *Sent:* Saturday, June 09, 2018 5:57 PM
>>> *To:* hackrf-***@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
>>>
>>> _______________________________________________
>>> HackRF-dev mailing list
>>> HackRF-***@greatscottgadgets.com
>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>
>>>
>>> _______________________________________________
>>> HackRF-dev mailing list
>>> HackRF-***@greatscottgadgets.com
>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>
>>
>> _______________________________________________
>> HackRF-dev mailing list
>> HackRF-***@greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>>
> _______________________________________________
> HackRF-dev mailing list
> HackRF-***@greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>
Dominic Spill
2018-06-26 23:40:51 UTC
Permalink
It's possible that we could add an option for this, but I wouldn't want to
make it the default because there are times when we don't want to turn it
off when switching back to RX mode.

Dominic

On 26 June 2018 at 16:51, Chuck McManis <***@gmail.com> wrote:

> Or to put it differently, :-) If the HackRF would enable the ANT bias when
> it was transmitting then it would "just work" as they say.
>
> On Tue, Jun 26, 2018 at 11:18 AM Gavin Jacobs <***@hotmail.com>
> wrote:
>
>> Dominic
>> Thanks for that offer/suggestion, but it’s already done! I found the TX
>> mode signal that drives the TX LED, and it was already brought out to P5.
>> So All I had to do was solder some ribbon cable to P5 socket (which is not
>> populated). I have it connected to my power amp such that it energizes
>> whenever the Hackrf is in transmit mode.
>>
>> Jake
>>
>>
>> On Jun 26, 2018, at 10:59 AM, Dominic Spill <***@gmail.com> wrote:
>>
>> 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 <***@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 <***@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 <***@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 <***@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 <***@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-***@greatscottgadgets.com
>>>> <hackrf-dev-***@greatscottgadgets.com>] *On Behalf Of *Gavin Jacobs
>>>> *Sent:* Saturday, June 09, 2018 5:57 PM
>>>> *To:* hackrf-***@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
>>>>
>>>> _______________________________________________
>>>> HackRF-dev mailing list
>>>> HackRF-***@greatscottgadgets.com
>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>
>>>>
>>>> _______________________________________________
>>>> HackRF-dev mailing list
>>>> HackRF-***@greatscottgadgets.com
>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>
>>>
>>> _______________________________________________
>>> HackRF-dev mailing list
>>> HackRF-***@greatscottgadgets.com
>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>
>>>
>> _______________________________________________
>> HackRF-dev mailing list
>> HackRF-***@greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>
Giuseppe Marullo
2018-06-27 10:13:24 UTC
Permalink
> Or to put it differently, :-) If the HackRF would enable the ANT bias
> when it was transmitting then it would "just work" as they say.
Definitely I would vote for this. Maybe we could "link" the TX LED
signal with the BIAS using a little hw "bridge" so not to rely on any
sw change.

Giuseppe Marullo
IW2JWW - JN45RQ
Chuck McManis
2018-06-27 19:25:36 UTC
Permalink
It is a bit more complicated Giuseppe than that. You see there are systems
which have active antennas (powered) for receiving. In such a system you
can use the antenna bias to provide power to the active antenna elements
(typically a filter bank and an LNA). Those are typically receive only
systems. Systems that have a dedicated transmit port can "hard code" the
bias-T on that port and switch on or off bias on the receive port. But if
you only have one port there are times when you want the bias on all the
time (operations with an active antenna) and times when you want it only
during transmit (PTT / bias-t applications). A software option that lets
you choose how it behaves is the best overall solution.

--Chuck

On Wed, Jun 27, 2018 at 3:13 AM Giuseppe Marullo <***@marullo.it>
wrote:

> > Or to put it differently, :-) If the HackRF would enable the ANT bias
> > when it was transmitting then it would "just work" as they say.
> Definitely I would vote for this. Maybe we could "link" the TX LED
> signal with the BIAS using a little hw "bridge" so not to rely on any
> sw change.
>
> Giuseppe Marullo
> IW2JWW - JN45RQ
> _______________________________________________
> HackRF-dev mailing list
> HackRF-***@greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>
Giuseppe Marullo
2018-06-27 22:59:50 UTC
Permalink
Agreed,
But assuming the hw model could be disabled by a little switch you won't need any software change at all and retain bias ability for rx only applications.
If using software is that easy, then there should be no problem to activate bias and tx function at the same time.
I guess that not all the programs able to tx are able to do it, hence the idea to link the two together at hw level, but maybe I didn't get the whole picture.

Still today is not clear to me how to drive in tx the hackrf looking at gnuradio example diagrams, go figure if I know how to sync the bias at the same time.

On June 27, 2018 9:25:36 PM GMT+02:00, Chuck McManis <***@gmail.com> wrote:
>It is a bit more complicated Giuseppe than that. You see there are
>systems
>which have active antennas (powered) for receiving. In such a system
>you
>can use the antenna bias to provide power to the active antenna
>elements
>(typically a filter bank and an LNA). Those are typically receive only
>systems. Systems that have a dedicated transmit port can "hard code"
>the
>bias-T on that port and switch on or off bias on the receive port. But
>if
>you only have one port there are times when you want the bias on all
>the
>time (operations with an active antenna) and times when you want it
>only
>during transmit (PTT / bias-t applications). A software option that
>lets
>you choose how it behaves is the best overall solution.
>
>--Chuck
>
>On Wed, Jun 27, 2018 at 3:13 AM Giuseppe Marullo <***@marullo.it>
>wrote:
>
>> > Or to put it differently, :-) If the HackRF would enable the ANT
>bias
>> > when it was transmitting then it would "just work" as they say.
>> Definitely I would vote for this. Maybe we could "link" the TX LED
>> signal with the BIAS using a little hw "bridge" so not to rely on any
>> sw change.
>>
>> Giuseppe Marullo
>> IW2JWW - JN45RQ
>> _______________________________________________
>> HackRF-dev mailing list
>> HackRF-***@greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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