Radio troubles of a sailor and the promises of software defined radio (SDR)

[JSantos]

Hi,


Marine VHF bookmarks for CubicSDR


(check my radioforcruisers.blogspot.com for more information)


Rationale:
"Such bookmarks can be used to
- a fast scanning of VHF channels with information on the expected content (instead of the “blind” experience with a marine VHF or Ham radio)
- to record at scheduled times the notices to mariners, safety or other useful information (channel 16 …)
- to use in conjunction with data/digital modes software (Fldigi, other free or paid digi mode apps) to see/record navtex, weather fax, etc."


Fair winds,
Jorge

[flyingnut40]

follow

[JSantos]

In short.



My firm belief : the best sailing boats are those of friends and charter companies.

However, by 2006, I had become more and more concerned with safety and reliability issues of the navigation tools available in such boats.

So, I decided to build my one portable pack of navigation tools with two main criteria:

• safety, reliability, ease of deploying and using in any sailing boat I intended to skippering;
• compact enough to be carried in a cabin case.

By 2007 I was very happy with almost all of my own set of navigation tools. The notable exception: radio hardware and software to receive timely safety warnings, notices to marines and other useful information.

Therefore, I decided to start a systematic search and test of possible solutions. First decision: the best approach would be to experiment with mid range SDRs. The ones which are serious pieces of radio hardware/software (check radio ham reviews) in spite of its funny names. For example, HackRF, AirSpy or SDRplay with tag prices in the range of 100-300 Euros. Unfortunately, by 2008 I started facing severe personal problems. And both, my sailing holidays and radio equipment tests have been postponed.

So, in short, the motivation for starting and to post maybe a half dozen of messages, is quite simple: to share the results of my past research on portable radio solutions for skippers. No, I did not reach a “definitive solution” but at least my test results might be useful for other skippers and maritime radio hardware and software developers. And hopefully, I’ll be able to post further and new tests in a foreseeable future.



(check radioforcruisers.blogspot.com for an extended version of this message).


Fair winds,
Jorge

[ohgary]

AS a ham I love the if SDR radios, Lots of option to play with to filter out weak signals. . For SSB marine radios most of the "SDR" part is going to be hidden behind simple controls. While the radio might be SDR, the user interface will remain pretty much the same. Turn on, and talk..

[JSantos]

Hi,


(extended version in my blog, radioforcruisers.blogspot.com)


Or, given the goals and the available radio sources (check my previous post about the background and motivation )what are the feasible options for a cruiser?

Goals: to have a portable, yet easy to deploy, reliable and easy to use system

What radio sources of timely safety warnings, notices to marines and other useful information?



Navtex, RTTY-DWD, WeatherFax, VHF, SafetyNet/EGC and,
Wifi/3-4-5 G (not the scope of this post)


So, repeating the initial question of this post, why a SDR approach to portable radio reception for cruisers?

First, let us face it, even the “fixed” systems often found in leisure vessels are not satisfactory. Second, there is no such thing as a conventional piece of hardware, a portable classic radio receiver able to cover the entire spectrum for the sources listed above.


Therefore a SDR, mid range unit with a price tag of 100-300 Euros, seems the best option. Several models in this range are able to cover all the spectrum from the low/medium to the ultra high frequencies. Furthermore, for each radio broadcast frequency we could select the best, built in filter/amplifier. No need to play with several small pieces of hardware, connectors and cables as with those so called “cheap dongles”. Finally, paired with the proper antennas such SDRs could receive all the voice and data messages of interest for cruisers. With a quality that matches higher-end transceivers (check Ham forums, the Akos blog radioforeveryone.com and other commendable reviews).
For example, SDRplay RSP 1A (for single antenna coupling) or the 2 or Dx models, that might be paired with up to three antennas simultaneously, thus really covering all the spectrum of interest for us. Ie., (1) a simple wire antenna for navtex, rtty, weatherfax and M/L frequencies in general, (2) a VHF one for well … receiving/recording vhf channels and (3) a patched or equivalent antenna for receiving data from satellites.

(more on technical specs, examples and tests of SDRs, antennas and software in future posts).



Fair winds,
Jorge

[AA3JY]

If internet connected for your listening pleasure..
Websdr.org

[JSantos]

SDR Hardware

SDRPlay RSP 1A
Continuous scanning from 1 KHz up to 2 GHz, therefore covering all radio the frequencies of interest for cruisers, i.e., for receiving voice calls and check text or image files, with notice to marines or other useful information.
Of course, also quite good to just enjoy all AM or FM radio broadcasts. At least as good (reception) as a high-end classic transceiver (check Ham forums, blogs and other reputable sources). Plenty of support and a very dynamic users community.


USB Cable
As long as needed, with plenty of ferrite chocks to minimize RF noise from the computer to the SDR unit.

Computer
Because with a SDR setup we need a computer to run the software part of it, at least a tuner. Mine is a MacBook USB-C, portable, light, fanless, with a UNIX foundation and the best user interface. But choose what fits your preferences and needs.

Imuto PowerBank X6L Pro
Optional, good to minimize RF/electric noise from the computer power adapter and electric grid. At least when to try to receive very weak / prone to noise broadcasts, in an emergency, etc. For marine purposes the best would of course be an almost direct connection to a 12V battery.

Sony Headphones MDR-7506
Optional but highly recommended. Vastly improves the tuning/listening experience. And let us face it: our radio excitement, at home or while sailing, is just a source of nasty noise to our friends and family.

Software

CubicSDR v0.2.3.
The tuner part of SDR. Choosed because it supports SDRplay and works directly in MacOS. Free and open-source. Good interface. Rare upgrades. Out of the box anyone can listen broadcasts with SDRPlay/CubicSDR with a quality as good or even better than with a classic radio. But, to real get the best results there are lots of adjustments to be made. Read the manuals and other information. Test, re-test, record, compare, before asking for help.
For non window users, the SDRPlay team used to propose to run their one app with a virtual machine under Mac or Linux. Not sure if they still insist on this misleading nonsense. Yes, their app SDRUno would be the best to get … the best of their SDR RSP. For a stand alone, probably critical system, forget it. Skippering a boat is already quite demanding. No need to waist time with slow, unreliable and crashing computer systems.

QjackCtl 0.3.6
Virtual cable/jack needed to transfer sound to a data/digital software. Should work like a real cable to connect a classic radio to a modem and the modem to the user interface. Rare updates and almost no existing support.

EGC-decoder-v08
For SafetyNet / Inmersat Solas safety and other useful information. Not tested, because of personal reasons, totally unrelated to this piece of software, the author or radio issues.

Fldigi-4.0.16
To get navtex, rtty, weatherfax and all sorts of data/digital modes useful for cruisers. Coupled with a transceiver acts as a bi-directional software modem (not explored here). Runs in almost any platform. Frequent updates. Live and helpful community. The user interface might be as expected for ham and professional users; but will be likely evaluated as very awkward by a UI and HMI expert. The learning curve might be quiet long. Read carefully the manual, faqs and other material before asking for help.
With my setup I had no problems with digital modes if, and only if I used this combination of CubicSDR-Jack-Fldigi for just a few hours. But I never succeed in running the system unattended for extended periods of time. Maybe this chain works better with other hardware/software combination.

Or maybe we need here a community effort, as with OpenCPN, to build a cross-platform, integrated, reliable and, easy to use radio reception software for cruisers.


Fair winds,


Jorge


PS. Check radioforcruisers.blogspot.com for an extended version of this message.

[Discovery 15797]

I don't mean to be a kill-joy, and SDR is cool technology; however, this seems like a marginal solution to a non-existent problem.

We are 10 years past your original conception, and there are way better solutions for obtaining way better information such as the internet (near shore) and satellite (offshore).

[JSantos]

Hi "Discovery",


Thanks for your reply.


You might want to read the extended version of my messages at the blog on

Internet and Satelite sources.


And yes, I'm also an early adopter and heavy user of Internet for both planning and checking maritime info. But "internet" is not and probably will not be in the foreseeable future a Solas/ECDIS accepted standard for navigation, nor a replacement for the mandatory radio sources. And for very good safety reasons.


And yes, certain satellite sources are not only interesting but also part of the mandatory Solas/ECDIS at least for some types of vessels. But, well, satellite voice and data reception/transmission is achived through GHz RADIO waves ...


Fair winds and thanks again for your message,


Jorge

[JSantos]

Hoops!


In my last message instead of .../ECDIS it should be .../GMDSS: Global Maritime Distress and Safety System.


In this forum, ECDIS (Electronic Chart Display and Information System) might a topic to discuss in the for OpenCPN users and developers section.


Jorge

[JSantos]

Hi,


Ham enthusiasts are far more competent than myself to elaborate on this subject. But it seems that a good antenna is mandatory.


My choices both for MF/HF, SSB and VHF
- after reading a lot, plenty of good sources around;
- considering my needs – portable and easy to pack even in a cabin case, easy to deploy in the chartered boat, good to receive the desired frequencies with my SDR RSP 1A.

MF/HF, SSB
Voice, data as Navtex, DSC-RTTY, WeatherFax ….

A rope antenna of around 8 meters, fits well in a sailing boat from a 28 feet monohull to big catamarans. Hanging from the mast to a rail in the stern as far as possible of the backstay(s) but without interfering with the boom and main sail.

- wire of the appropriate length (not a random one, use online calculators) --> coax cable -->connector to SDR
- embedded in a 12 strands single braided polyester rope with two eye splices

VHF (and/or AIS)
Mainly voice, data limited (?) to DSC and AIS frequencies

I found that a standard, commercial antenna was more than adequate. (And no problem to bend it to fit the airplane bag)

Ram mount for antennas fixed to a suitable rail --> antenna --> coax cable --> connector to SDR


(Check radioforcruisers.blogspot.com for an extended version of this message)



Fair winds,
Jorge

[Pizzazz]

Jorge,

I see where you are coming from but just because SDR is a cool technology, it does not mean you can find a maritime application for it.

Maritime radio is channelized for a good reason, it helps you do your job quickly with minimum distraction. Navtex is pretty much dead in the US for leisure users. HF is affected by the 0 sunspots for years. Satellite is all the rage these days.

SDR could be cool as a hobby or if you are eavesdropping on other signals. But these signals will be encrypted and probably super boring if you were to decrypt them.

My advice, if you like this stuff, drop HF and learn about satellites.

[conachair]

Originally Posted by Pizzazz

My advice, if you like this stuff, drop HF and learn about satellites.

Unless you want to head offshore, where for a lot of the world weatherfax charts are such a fantastic resource. Masses more out there than just marine SSB. SDR might be heading a bit geeky. no doubt much easier for most just to get a cheap ssb receiver but SDR could be a very useful & cost effective way to get wfax, plus listen in to all the other stuff going on. Local airport automated weather broadcasts can be handy for actual wind conditions, lots going on on the airwaves. This does tend to be a very affluent forum mostly but not everyone is dripping with cash to splash out on sat, SDR might be of minority interest, but still of interest.

Keep it up Jorge

Would cubicsdr compile on a Raspberry Pi?
I've had gqrx running on a Pi3 but something weird has happened to sound on the new raspbian on a Pi3B+ , haven't got it working yet. But really interesting when it was, with a funcube dongle pro plus. Scan from basically DC to over 2GHz.

[JSantos]

Hi "Pizzazzs",


Thank you for your advice.



You might want to check my previous messages in this forum and my blog (radioforcruisers.blogspot.com):


- my interest in SDRs and navigation is very specific, not to solve all the problems, not as replacement of other systems

- no problems with "new" approaches and technologies, satellites and so on,

- well aware of all the questions you mentioned,
- also quite informed about international regulations and safety issues,
- almost all my navigation in European waters so my needs and concerns might be a little different from US cruisers.


Fair winds and thank you again for your message


Jorge

[JSantos]

Hi Conachair,


Thanks for your kind message!


About your questions:


It seems possible to (1) compile CubicSDR on a Pi (2) to install api/drivers/server for SDRPlay, (3) to install a SDR image with several software tuners but not CubicSDR, etc.

But I never tried to configure a Pi for SDR. I've one Raspberry Pi 3B but just to listen Spotify and my ripped Cds at home (HiFiBerry DAC+, Volumio).


Good luck and keep me updated!


Fair winds,
Jorge