Operational with RF-Systems preselector and USB powerbank

Today I did some tests with powering the unit with a 5V power bank. The 5V lead uses the same connector on the back panel, which has 4 poles, two for 12V and two for 5V. So one power supply can be used at a time.

Also the RF-Systems P-3 preselector works great in combination with the SDRplay. An EF-SWL longwire for RX only was used.

The EF-SWL longwire is a rugged, very portable HF antenna that yields stunning results. Highly recommended!

[See the EHAM user reviews here. It gets a solid 5.0 rating after more than 40 reviews - there is no other item with a comparable rating.]

On the left the 10400 mAh power bank. On top the HF preselector.

Preselector on top.

First stage now finished. See pictures.

My double-SDR is now halfway finished: It is operational with the SDRplay only. After summer, I will add the next two modules, the AirSpy and some converter, either the Spyverter or the SV1AFN - have not decided yet.

A picture tells more than 1000 words, so here is the story:

Testing indicator LEDs behind diffusor, enclosure not ready yet

Rubber feet

Velcro strip for SDRplay

Provisional sticker

Serious nuts & bolts

USB cable is led into case without connector

Back panel, one RF-connector still missing (for HF converter input)

Paper template to check if things will fit

I will summarize the concept of my project once again. I consider the SDRplay and the AirSpy as modules, not as devices. I want to have two SDR's under one hood, so I can employ either receiver in the appropriate situation. No module can be fed by the USB host at all. There is a separate 13,8V input (batteries, linear power supplies) and a separate 5V input (cheap power banks).

One Year Later: let's start building

After some "time consuming considerations" (one year!) about the logic around the RF modules, such as DC feed lines, switches, earthing, ground loops, common mode line chokes, decoupling C's, feed-throughs and much more, I finally started to assemble the enclosure that I designed earlier.

The enclosure in a raw state - plastic protection, no panel holes yet. All
Aluminium plates and profiles are 2 mm thick and all nuts and bolts are stainless steel.

About logic: There will be one DC connector with 5 poles. Three different DC cords will be assembled. Of course, you can use one at a time, for different purposes. Cable 1 is for 12V DC sources. The 12 V DC will be lead to the internal linear 7805 converter. In this case, you can run either one of the receivers, or both simultaneously. Cable 2 is for 5 V DC sources which feed either one of the receivers - running two receivers is not enabled. Cable 3 is also for 5 V DC sources, but by short-cutting two poles of the chassis jack, running both receivers simultaneously is enabled. The latter is meant for using 5 V power supplies that are powerful enough to feed both receivers simultaneously.

Some switching and feeding logic

But as always: I may as well change everything while building the thing. And as long as it is a hobby project, everything is allowed!

Next step will be: A copper plated epoxy carrier board will be placed onto the bottom plate of the enclosure; This will be the underlayment for all circuitry. This underlayment will be galvanically connected to the enclosure at one single earth point.

Some parts that I may need



Waiting to be mounted...

Panel cut-out sketches. Has changed a zillion times already.
And no boss who complains! Hobbies are a sanctuary.

STAY 'TUNED'

At this moment, various parts, kits and modules are on its way to me by mail. That will take some time. Furthermore, I don't have very much time for hobbies at the moment. So it will take some time before an update will appear here!

As soon as there is something new to tell, I will let you know in the SDRplay FB group.

INTRODUCTION AND GOALS

Building the Thing
This blog is entirely dedicated to one project: building both the Airspy SDR (and its future SpyVerter) and the SDRplay in one solid enclosure.

Why two SDR's?
Every SDR has its idiosyncrasies. Building two in one case makes it a solid tool with enough hardware on board to fit different needs. And it offers an ultimate opportunity to compare the usability of both SDR's in the field.

The main objectives are:

* Powering the active devices from separate linear power supplies and batteries, thus cutting the 5V USB lead; A 4 pole male XLR connector will be used as a DC receptacle;

* Apply as much protection as possible against unwanted signals such as USB noise and protecting against cables and leads that may work as an antenna;

* Create a very solid and RF-tight enclosure that can withstand intensive use in the field and leaves room for future hardware extensions that need to be placed 'under the hood'.

'Faraday Cupper Mesh' I picked up at the metal store. Destination still unknown.

The case

Earlier I crawled the whole internet for readily available commercial  enclosures but none of them fitted my needs. So I decided to design my own.

The design…

…includes a lot of room for the units, sidekick devices and possible future extensions;

…is made of aluminium plate, thickness 2mm and aluminium profiles, angled ½π, sides of 20mm, thickness 2mm;

…will be kept together by stainless steel hexagonal screws and NOT by pegs;

…provides easy access to all areas in the case;

...includes an inside area of which the dimensions form a golden rectangle.

Fake branding

In my country, the frequency domain for wireless microphones is rapidly shrinking because these domains are conquered by 4G networks. Soon I will offer on-location RF surveys and advice production companies (TV and live entertainment) which frequencies are vacant for solid wireless connections.

But I don't want them to look over my shoulder and steal the trick. So I will provide the case with a Russian brand name and model designator, such as 'Vasyljev XTR-320'. Googling this will end up in nothing and nowhere. Or herewhere.

[Update:] More secret whys
There are actually a few more reasons than the ones mentioned above. I love craftmanship. I love ruggedized equipment, as I often see in rude environments such as oil and gas production sites and platforms. I love the fun of fake branding. I love to have choices: either switch on SDRplay or AirSpy mini.










WILL BE CONTINUED HERE!