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Informations about: Hydra, the 10 Ghz Frontend
Update Sept. 19, 2020


DUBUS 3/2020 was released in Sept. 2020.,

10 Ghz Extension for Adalm-Pluto(tm)
(To subscribe to DUBUS, the bilingual magazine for the serious VHF and up operator,
click here: www.dubus.org)

....on this page you will find news, bonus material, FAQ and more...

What is Hydra?

"A 10 Ghz Extension for Adalm-Pluto(tm)"
Hydra is a minimal 3cm band frontend, enables you to use SSB/FM/CW also on 10Ghz.
The size of the PCB is made for a fit on the ADALM PLUTO (tm by Analog Devices)
which is also called PlutoSDR. Hydra originated from one developments for
El Cuatro, the multiband UHF/SHF receiver, see link below.

Where is Hydra?

First of all, Hydra is just one of the moons of Pluto, you cannot see it in the skies
but the 10 Ghz frontend with the same name is here:
X-Band (10Ghz) for ADALM-PLUTO

NEWS about Hydra V1/V2, and different versions:

2 versions are now in the making:

Hydra V1:

as described in DUBUS 3/2020, is now the low power version. TX power is
about -3dbm. With tuning of the input line with a small capacitor, the output is
higher. PCB color is yellow or red. Available now.

Hydra V2:

Hydra V2, which will be available in October 2020, has one additional TX amplifier,
see detailed description below.

Hydra V3:

Hydra V3 is same as V1, but without antenna switch. RX and TX is available on different
SMA connectors. available now. see detailed description below.

Frequently Asked Questions - FAQ

(please send mail for the Q&A, all answers will be available here.)

What is the price including shipping?

I have a few pcbs Hydra V1 now, that I will give away for the "early bird" price of
EUR 99.- Shipping is 15.- to EU countries. Worldwide 20.- or 25.-
Paypal is preferred.

How can I order?

Please send email (address see below) to me, including your shipping address. I will
contact you once i am ready to send the pcbs out. The first few pcs of the Hydra V1
are shipped already. Hydra V2 is available in October.

What software do you use in general for Pluto?

Currently I do only the hardware, but my friends use SDRAngel, SDR-Console,
GNU-Radio and the Langstone project software. Once I have tried every possibility
myself in software, I will report here.
For now it seems that the Langstone software, with Raspberry Pi4 and 7" display is the
best for QSOs, but for testing purposes other solutions may be preferred.

...but the professor said, SSB signals cannot be multiplied?

The preferred way for SSB is one more block in GNUradio, to reduce the
modulation bandwidth, so it is correct after the doubler. Will publish more information
here when available.

Applications:

-Amateur radio
-Portable testing equipment
-Microwave portable equipment

Other Published Articles:

Information about the El Cuatro FM/CW Microwave Multiband Handheld Transceiver, published
in DUBUS 3/2018 is here

Updates to the Hydra Article, published in DUBUS 3/2020:

The following clarifications to the schematic are found:
- on the +5V TX Line, the 100pF Capacitor should be very close to XX1002.
- both +5V TX and +5V RX line need a 3k3 resistor to ground to ensure switching
voltages at the specified range, 0-0,2V.

Hydra V1 description:

is a extension for the ADALM-PLUTO (tm by Analog Devices) learning Module, and enables
the use of the 10Ghz Band (10368-10370, 10400-10450) and beyond. From a former project
"Hydra V0" was reused, current available PCBs are "Hydra V1". For a detailed
description, PCB layout and schematic see DUBUS 3/2020.
X-Band (10Ghz) frontend for PlutoSDR
Typical TX power for V0 or V1 is abt. -3dbm, Noise-Figure is around 10db. Mode is SSB/CW/FM.
Pluto must be set to (e.g.) 5184Mhz for TX and receiver must be set to (e.g.) 618Mhz.
Any more questions? Please email me and the answers will be added to the FAQ.

Hydra V1 package contents

Hydra V1 package contents
Hydra V1 is shipped in an antistatic bag, with one SMA plug not mounted, this has to
be fittet to your Adalm Pluto, as the distance between the SMA connectors is slightly
different. The cable on the top is for +5V, manual switch is mounted for testing,
but can be replaced by a relay (which is switched from USB or Raspberry PI port)
The board is tested for TX and RX performance, RX/TX function and that the 25Mhz
oscillator is continuously running.

Hydra V2 description:

Hydra V2: (blue) Because we could not establish the monthly QSO over a distance of
96km on 10369,500 in FM, it was decided to add a amplifier stage to get more TX power.
new: Hydra V2
This is the first manually assembled Hydra V2 board. Very small parts, the smallest
part is 1.5x1.5mm. The good news, I get used to assemble the board under the stereo
microscope in 5-10x magnification. More informations soon.

Description of Hydra V3, the headless Hydra.

Hydra V3 is without the antenna switch, there is a seperate SMA connector for TX
and a seperate connector for RX. You can add PA, LNA, filters and antenna relais
yourself as needed.
new: Hydra V3

Be aware, that this is very experimental. If you are serious
about activity on 3cm, please consider using a transverter.

Bonus material, which was not available
in time for DUBUS 3/2020

RX/TX switching:

is always done with the same footprint for +5V TX and +5V RX.
It can be done manually:
- with a miniature switch (e.g. Hartmann SX254)
- With a small SPDT switch (see photo)
Hydra X-Band RX/TX switching
or automatic from your Raspberry, laptop or PC:
- With a mechanical SPDT relay, which can be a seperate USB relay
- or a relay driven from Raspberry Pi 3.3V Pin (like Langstone project).
- The relay then provides +5V RX and +5V TX seperately to the pads, see above.
So no +5V supply to the Hydra PCB and no manual switch is needed.

LNB LO Options:

The LNB in default configuration works with 9750 Mhz (25Mhz x 390). The LNB
features also a "high band", where the multiplicator is 424 which gives 10600 Mhz
LO (25Mhz x 424). You can remove the 25 Mhz Oszillator and feed your own frequency
as a reference frequency. I successfully used 24,1 to 25 Mhz, but 26 Mhz failed.
So you could adjust the receiving frequency also to 144 or 432 Mhz, if you want.
So for synchronous receiving with several RCVRs you only have to feed the LNBs with
the same phase of reference signal.
Hydra X-Band frontend LO mod

About the author:

Fred, OE8FNK, now also microwave manager in OE, is doing UHF/SHF amateur radio for a
lifetime. His background is microprocessors and software, but interest radio and radio
astronomy made him build electronics and RF. All equipment is made to enable
others to participate in UHF/SHF activities, and to create local activity on
microwaves bands (70cm-3cm), often within the local club or district. This is done
with the absolute minimalistic equipment, and the least possible TX output power,
but encourages some to maintain their equipment and activity on microwave bands.
We are making contacts over a distance of 60-100km monthly in activity contest,
with 0.0003 to 0.06 Watts now for many years on frequencies from 1-10Ghz. Results are
documented and available at http://mikrowelle.oevsv.at



Do you need something for 24GHz? Click here for more information about the 24Ghz
El Cuatro EC24 on the "El Cuatro" Website.



Still reading? Any more questions? Appreciate your comments and feedback :-)


oe8fnk

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