Monday, November 29, 2021

Doing "data stuff" over VHF/UHF FM?

First, let me set up a user scenario so this makes sense as to what problem is being solved.  

Imagine you are somewhere where you have a fully charged smartphone, but no network access of any kind along with a dual band handheld amateur radio.  

Aside from the above, you happen to have some type of HF radio with you, but you forgot a few important things at home like a Morse code keyer and some important thing that prevents you from powering your HF radio, like a power cord, fuse, etc. 

Your only method of outside field communications is with your handheld radio now! 

Luckily, you have a few extra things  with you such as an Easy Digi Interface and a USB-C to 3.5mm adapter with you. How can you communicate using non-voice modes?

Sending certain data signals over FM provides some benefit. Lets explore a few of these where you will be connecting your smartphone to your handheld radio.

Smartphone Headset Adapter

If you have a smartphone with a headphone jack, that is great but is feature becoming less common.

The latest Android or Apple devices have done away with the standard 3.5mm headphone jack and is why you need an adapter that goes from USB-C (Or Lightning) to a 3.5mm jack.

For $9.99, this USB to 3.55mm TRRS headphone adapter gadget can be yours and will find many other uses you can think about.  Support fellow Hudson Valley club OMARC by using Amazon Smile.



Easy Digi Interface

This simple box allows you to connect your smartphone to your handheld radio.  You may or may not need the smartphone headset adapter, but lets pretend you do.  

It is now simple for you to connect your radio and smartphone together thanks to KF5INZ and the appropriate version of his adapter for your radio. Below is pictured the version appropriate for the Alinco DJ-MD5XTG DMR radio along with the USB-C to 3.5mm TRRS adapter.

An alternative option, but still using a different form of the Easy Digi Interface was even written up by HVDN's Joe NE2Z back in 2019.

Do Not Leave Home Without Software

Since you do not have network access to download applications on your smartphone in this described scenario, install a few before you get stuck somewhere.  

The first application to focus on is one that you can send pictures with.  SSTV and its different modes offer different benefits and this ability might come in handy to increase situational capabilities.

The second application to focus on is something that can send text data in a conversational format.  Modes like RTTY and PSK31 are great for this as they work just fine being sent over FM.  Small or large amounts of text can be shared with these modes. VARA FM is not a focal point in this article since we are focusing on basic implementation for basic users.

A third application is something where you can share your location and short embedded messages.  APRS.  APRSdroid is a great way to start related to APRS without a dedicated APRS radio. 

Here is the list of essential communications applications you should have on an Android device relative only to the use case described in this article.

Please note that similar versions exist for Apple devices, but HVDN can not provide comment/support on those, but we welcome your Apple favorites. 

Robot36 - Highly Recommended as SSTV reception application because of modes supported like PD50.

SSTV Encoder - Recommended for SSTV transmission via supported modes like PD50

APRSdroid - Highly recommended for sound card based APRS with appropriate interface cable.

droidRTTY - Recommended for RTTY over FM or other modes.

droidPSK - Highly recommended for send/receive of PSK using appropriate interface cable.

droidSSTV - Another SSTV option, but better options exist. 

AndFlmsg - Many supported modes but experience may vary based on your smartphone/tablet.

Wednesday, November 24, 2021

SIGpi: The automated way to install SIGINT

 


If you are interested in signal interception (SIGINT) and the convergence of amateur radio with non-amateur radio wireless interests,  SIGpi might be worth a look.

What makes SIGpi different than DragonOS is that you can control what gets installed versus just running an image. The benefit of DragonOS is a much faster time from download to actual use compared to SIGpi, but that is ok.

Both projects have one thing in common, which is making it easier to enjoy the world of software defined radio and focusing on things not just on specific spectrum or applications.

How easy is this?

In the case of SIGpi, it is optimized to run on a Raspberry Pi and will compile all the correct dependencies to allow popular applications like SDRangel to run along with pre-configurations needed for different hardware SDR like the HackRF or Lime SDR among others.

Getting Started

As long as you are running a Raspberry Pi 4 and a fresh install of the latest Raspberry Pi OS or Ubuntu RPI,  here is all you need to do:

  • Login as Pi (or ubuntu)
  • Create a directory in your home called source and switch into it
  • Clone the SIGpi repo
  • Run SIGpi_installer.sh
  • Follow script instructions.
To make things more clear, here are the steps you can simply copy and paste.

  1. sudo apt-get install -y build-essential git
  2. mkdir ~/source && cd ~/source
  3. git clone https://github.com/joecupano/SIGpi.git
  4. cd SIGpi
  5. ./SIGpi_installer.sh
How long did you say this takes?

Even on the latest Raspberry Pi 4,  compiling software still can only happen as fast as it can happen. This is why Joe Cupano NE2Z chose to make an easy guided menu system to allow you to install only what you want and even give you time estimates for it to install. 

Aside from the default options already selected, you can further customize what else you wish to start with. Once you are done, now its time to hurry up and wait.



What is included in SIGpi?

The current list of included and validated software included in SIGpi can be found at https://github.com/joecupano/SIGpi.    It is worth mentioning that SIGpi was a necessity for a wider project called SIGbox which is covered separately. 


An example during the install script relating to different types of
radiosonde signals which can be decoded using appropriate
hardware, antenna and SIGpi






Monday, November 15, 2021

The perfect tape measure beam for RDF?

 

There are lots of instructions and videos about the 2m tape measure beam available already.  Here are some build ideas based on the different iterations I have built over the years which are originally based on Joe WB2HOL's version before he went SK.

Please visit: http://theleggios.net/wb2hol/projects/rdf/tape_bm.htm 

Mounting the directive and/or reflective elements

Rather than using small hose clamps to secure the elements to the boom, I originally used zip ties. This method worked well, but sometimes warped the elements at an angle.  Using electrical tape works better, is easy to replace, cuts down on weight and improves the radiation pattern of the antenna.

Using electrical tape is inexpensive, secure, neater and
does not influence the antenna pattern like hose clamps do.
(Photo Credit: Steve Bossert K2GOG)

Boom Material 

1/2 inch PVC T and crosses seem the best.  A few antennae I made used 3/4 inch conduit and junctions to improve ruggedness, but 1/2 inch has proven just fine and weighs less.  Only use PVC cement once you are happy with the construction to secure the junctions to the boom pieces.  

Friction fit construction may fail at the worst possible time, so glue your junctions.  The only real major benefit of 3/4 inch construction is that your elements can easily slide into them for storage or transport.  This is still possible with 1/2 inch fittings but is a little too tight and the elements will take up more room during transport.

Here is a 2 element version with the director and driven elements folded up.
(Photo Credit: Steve K2GOG) 

Is a current balun necessary?

After making identical versions of  2 or 3 element antenna with or without the balun, I find the pattern of the antenna is more stable with the balun.   Making sure the balun is close to the feed point is a really good idea.   

I drill two pair of holes a few inches apart to form the balun and the feed point goes into the boom for a clean construction. Drilling the holes as far to the interior of the PVC cross is a good idea in order to leave room for folded element storage.

Where the nut inside the PVC cross is where a crimp ring slides over the screw and is the secured by the nut. Outside the PVC cross is a washer and nut. Outside and on the top of the driven element is a star washer on top of the hairpin match.



Scrap off the tape measure paint on both sides. Use a little De-Oxit to ensure excellent conductivity and to prevent any future rust. The 5 inch hair pin match is made from steel clad copper wire and crimp rings with the insulator removed are used to ensure secure operation. The crimp rings are also soldered to the hair pin match for further reliability.  A flat and star washer keep everything tight together.

How to connect your radio to antenna?

I like making a neat looking antenna and I route the RG-58 through the boom and out the back end.  You can make a long tail with a BNC male on the end to connect to your radio or via an SMA to BNC adapter.  Here is what a 3 element version of the antenna looks like configured that way.


The other option is a little more technically challenging to describe where a female BNC is fitted on to the end of the boom instead.  For the photo below, I also drilled a hole to secure a length of 550 paracord to act as a wrist strap of sorts.  

Using a short jumper cable to connect to the radio is needed, but when traveling, not having a cable dangling is a nice benefit and does not offer that much signal loss or leakage if done nicely.


Make your boom grippy?

Self amalgamating insulation tape works great as a grip and it wont leave a sticky residue behind if you care to remove it later. This same tape is also great for protecting antenna connectors, so pick up a roll or two and I am sure you will find many uses for this stuff. 

Here is a 2 element and 3 element 144 MHz tape measure beam antennae using similar construction practices. Put some electrical tape on the antenna ends to prevent potential cuts or eye pokes.
(Photo Credit: Steve K2GOG)

Measurements 

Many articles like the WB2HOL article cover measurements and you can find what works best for you. The goal of this article was to focus on some construction improvements.

When tuning the antenna it is best to adjust the driven element for lowest SWR at your operating frequency first and then add your reflector or directors after. This should lower the SWR further.

You can squeeze the hair pin match element to get a better match and as long as you are using stiff wire, it will hold its shape. The hardware used in construction of these antenna do not noticeably affect the radiation pattern of the antenna.

If you plan to transmit with these antennae, please ensure you adjust for a good SWR to protect your radio transmit circuitry.

Using these antennae

The original use for this design was for radio direction finding, but both will also do just for for transmitting if you are interested in light weight directional antennae for use with summits on the air (SOTA) or other portable operating scenarios.

Remember, that there is a null in signal off the back of the antenna and to the sides. This will be helpful when finding hidden transmitters.  The null is more pronounced with the 3 element version, but the 2 element design works great for other reasons.

If you are looking for a fun and inexpensive project you can build, please give these a try.

Hudson Valley Digital Network in conjunction with other area amateur radio clubs will continue to hold hidden transmitter hunts, so please check our activity calendar for upcoming events.


Safety first.  Be sure to protect the ends of your antenna elements with
some electrical tape to prevent injury
(Photo Credit: Steve Bossert K2GOG)

Sunday, November 14, 2021

ARRL Hudson Division Awards (2020 & 2021)

Saturday November 13th was the  ARRL Hudson Division Awards Lunch which recognized various achievements across the regional amateur radio community in 2020 and 2021 right here in the Hudson Valley and slightly beyond into Northern New Jersey, New York City and Long Island.

Many prizes related to the ARRL's branding of "Cycle 25" were given out all afternoon as well as the usual ARRL publications, including some donations by a latter to be mentioned award winner.  

Ria Jairam N2RJ, ARRL Hudson Division Director, did a fantastic job in pulling this years event together along with the Orange County Amateur Radio Club and it was great again to have some form of in person event take place which the Amateur Radio Relay League was able to visibly lead.

Joe K1JT accepting an achievement award during the ARRL Hudson Division Awards Lunch from Ria N2RJ (Photo Credit: Joe  CupanoNE2Z)

The first featured guest speaker was  Dr. Joe Taylor K1JT, the inventor of so many of the low signal to noise ratio modes enjoyed by everyone involved in HF data communications via FT8 and FT4 as well as those with loftier goals via meteor, tropo-scatter and "Moon Bounce" communications who diplomatically befriend to make radio contact beyond our atmosphere such as JT65 and others.

Here is the new QRP Labs QDX SDR transceiver capable of FT8 plus other modes which we have Joe K1JT to thank  which Neil W2NDG and Steve K2GOG of HVDN recently received and are
quickly trying to build in time for WFD 2022 (Source:  QRPlabs.com)


Following Joe was David NA2AA, the current ARRL CEO, and he talked about everything from major changes taking place within the ARRL to help modernize communication via video based content to better ways to engage the the population which Hudson Valley Digital Network has already been focused on since our inception in 2017. David's discussion was refreshing and encouraging. 


In 2021,  HVDN has 37% of our audience coming from where the ARRL needs help. David NA2AA wants to find more ways to even more closely focus on the 30-40 year old population.
(Source:  HVDN Leadership Team)

It was really great hearing more about the changes that are needed at the ARRL at the national level and also at the regional level straight from the top.  

With the current ARRL CEO not being afraid to speak about his 11m days openly along with other topics which predecessors stayed away from, it should be exciting to see what is next within the ARRL, including "Project X", which hopefully HVDN can be a beta tester for via our upcoming events like HR3:2022.   

The Hudson Division with Ria N2RJ and David NA2AA have lots of work to do and it was great to see them again in person along with an impressive number of section leaders at a sold out event with approximately 100 people attending.

David NA2AA talked about solar cycle 25 and its importance it can have for the hobby for more than the next 11 years to help us grow during a time where much of the amateur radio community is not getting any younger. (Photo Credit: Joe Cupano NE2Z)

So many amazing awards were given out during the event, including those for technical achievements such as David WO2X's remote station projects using NodeRed and Alan W2AEW's energy put into his wonderful YouTube channel with over 341 videos and 159,000 subscribers.  


Alan W2AEW 2020 Technical Achievement and David WO2X 2021 Technical Achievement winners of the ARRL Hudson Division Awards presented on November 13th 2021
(Photo Credit: Joe Cupano NE2Z)

It was great to see one of the Hudson River Radio Relay leadership team responsible for the 2021 N2S station receive the 2020 Grand Ole Ham Award in part thanks to all his many years of being part of the amateur radio community  Congrats Adam AE2AN on this award!!


Adam AE2AN sharing a few words during his 2020 Grand Ole Ham award reception thanks to Ria N2RJ and her wonderful children who helped keep things on track in the later parts of the afternoon.
(Photo Credit: Joe Cupano NE2Z)

There were many other awards given which can be read about on the Hudson Division and sectional websites next they are updated, but lets close this article by highlighting the amateur of the year in the ARRL Hudson Division for this and last year since COVID prevented an awards meeting in 2020.

2020 ARRL Hudson Division Amateur of the Year:  Richie Cetron K2KNB

Richie is well known to many members of Hudson Valley Digital Network since a few of us used to live on Long Island and became good friends with him over the years, especially through using the wide coverage W2VL 146.850 MHz repeater while commuting or while at home.

Richie won this same award in 2012 for his leadership following the Hurricane Sandy disaster that disrupted life for so many.  Providing communications and social well being after a disaster like that was important and while Richie earned this award, he was quick to point out it was the work of many who made this possible.

Fast forward to 2021,  Richie earned this same award for the year 2020 for similar recognition which also helped ensure social comfort at the height of the COVID pandemic.  

While there were other amateur radio clubs such as the Mt. Beacon ARC and Overlook Mtn. ARC which also held social wellness discussions twice daily, the Long Island Mobile Amateur Radio Club which Richie is President of required a lot more effort to keep it running via many net control operators and many expensive to maintain repeaters which can be heard by all of NYC, Long Island, Westchester and elsewhere.   

Richie is a wonderful recipient of  an award like this and many amateurs can learn much from him in how he leads by example. Being President of LIMARC for now 11 years in itself is no easy task either, so this award is well deserved. Congratulations Richie!

Richard "Richie" Cetron K2KNB was awarded the prestigious 2020 ARRL Hudson Division Amateur of the Year award for his tireless efforts during the heights of the COVID pandemic.
(Photo Credit:  Joe Cupano NE2Z) 

2021 ARRL Hudson Division Amateur of the Year:  Steve Bossert K2GOG

2021 was a tough year and just like Richie K2KNB, the recipient of the 2021 ARRL Hudson Division Amateur of the year award earned this through his work in organizing a safe multi club, multi site special event called Hudson River Radio Relay.

The goal of the event was to help raise awareness for Bannerman's Island since they are funded by donations and tours. The pandemic affected the upkeep of the island and the surrounding communities of the Hudson River.  With eight participating special event stations, the event helped bring together more than ten amateur radio clubs and our local communities in a time of  little in person safe activities.

Steve Bossert K2GOG, one of the co-founders of Hudson Valley Digital Network and main organizer of the event, was given this award and is also the first award recipient in the ARRL Hudson Division for not being a current ARRL member.   It was fantastic that that ARRL chose to honor Steve with this award and is also a great way that shows that the ARRL advocates for everyone involved in amateur radio and not just its current members.

While Steve has only been a radio amateur operator for 23 of his almost 41 years of age, he has learned a lot from mentors like Richie K2KNB and many others who were either at this event or sadly, have passed away into Silent Key land.  Being able to lead and organize an event like this with so many unique challenges and personalities involved was a huge honor.

Success of the Hudson River Radio Relay event is widely captured in the local media and Steve was focused on highlighting so many of the people who helped make a first year event during a pandemic a huge success, even in challenging times, he barely spoke of himself. Here is a video of his acceptance and almost a the very end of a very nice lunch amongst peers of all ages.