[Discuss-gnuradio] FW: HF transmitter hardware solutions

[John Petrich]

Dan, Lou, Ron, and others,

Dan you are doing a great job of beating the drum: searching for "solutions
for transmitting on HF"  The question is a big one and can be broken down
into three basic issues.  The basic or elemental SDR platform solutions are
changing rapidly.  With the third generation SDRs, and tightly integrated
RFICs, there are a number of excellent, high performance, solutions, as has
been pointed out, and as you well know.

I think your real question, Dan, asks about the rest of the HF system: the
elements necessary to complete the transmitter for practical communication
purposes.  The question moves beyond SDR hardware to that of station
building.  That station building part of the system, I call the "interface".
The "interface" provides the receive and transmit filtering and antenna
switching, power control, amplifier stages, and other functions.  The
"interface" is built upon analog technology.  Much information along these
lines is addressed by the QRP (low power) movement within Amateur Radio.
The American Radio Relay League (ARRL) publishes small paperback books
devoted to QRP equipment and station building, and available for purchase
on-line.  The material covers homemade solutions, as well as purchased kits
and turnkey solutions.  Maybe, a group of interested GRC/SDR enthusiasts can
collect and publish a few example systems as starters for those who want to
experiment in this area.

The second aspect of the "solutions" question asks if there are suitable GRC
DSPs as starters, at least.  With Lou's help, I have authored a library of
transceiver DSPs for all of the commonly used HF transmission modes.  The
GRC DSPs are  'ham friendly' in the sense that they implement functional,
ordinary and familiar transceiver interfaces.  However, I have no easy means
to publish the DSP's.  Would collecting and publishing GRC DSPs be helpful
at addressing your "solutions" question?  If so, what is the best approach
for maximum visibility to the experimenter community?

Last but not least, a third issue for communication system functionality, is
to use the GRC GUI to control the auxiliary functions of an HF transmitter,
e.g. transmit / receiver relay.  I do not know of a means to access the GPIO
from the GRC GUI.  My present solution is to use current from the USRP
transmit or receive LED signal to control external equipment via a relay
system.  Maybe someone can publish a different solution.

Looking forward to further discussion on the HF transmit solution question.

Regards,
John Petrich

-----Original Message-----
From: Ron Economos [mailto:address@hidden 
Sent: Wednesday, April 6, 2016 7:23 AM
To: address@hidden
Subject: Re: [Discuss-gnuradio] HF transmitter hardware solutions

There's a transverter for the bladeRF.

https://www.nuand.com/blog/product/hf-vhf-transverter/

hackRF specification has been changed to 1 MHz to 6 GHz.

https://greatscottgadgets.com/hackrf/

Ron

On 04/06/2016 07:02 AM, Daniel Pocock wrote:
>
> What solutions are people using for transmitting on HF bands (1 - 30 MHz)?
>
> There is a lot of information online about upconverters for receiving 
> the HF bands.
>
> However, like receivers, many of the SDR transmitters only seem to 
> cover bands above 30MHz[1] e.g.
>
> HackRF:     30MHz - ...
> bladeRF :  300MHz - ...
> USRP B2x0:  50MHz - ...
>
> Is anybody using a downconverter or is there some other SDR model that 
> natively supports the HF spectrum and is accessible to hobbyists?
>
> Some other things come to mind:
> - power amps for HF bands
> - RF switches for using a single antenna in half-duplex mode, 
> alternating between receive and transmit
>
>
>
> 1.
> http://www.taylorkillian.com/2013/08/sdr-showdown-hackrf-vs-bladerf-vs
> -usrp.html
>