DJI Drones -- How it All Began (with a shout out to Frederick Terman)

Lots of interesting stuff in this video, including a short clip of non-other-than Frederick Terman, of Stanford University and Silicon Valley.  Like many of you, I have Terman's "Radio Engineer's Handbook" on my shelf. 

The Amazing Technological Development of DJI Drones

Yes, the ability to hover is a really big deal. 

Kalman filtering.  Who knew? 

GPS, compasses, intertial navigation, redundancy.  Great stuff. 

NZ showed DJI that quadcopters were the way to go.  

The importance of brushless motors. 

It is really amazing how quickly quadcopters took over from ordinary helicopters.  The regs in the DC area that prevent us from flying quadcopters here were probably developed BEFORE the quadcopters were developed. 

I still wonder about why we still fly normal helicopters:  Take you hands off the controls of a helicopter and it will soon start to flip and fall.  Take you hands off the controls of a quadcopter and it will just hover in the sky.  When the batteries get low, it will return to the start point and land.    

I have a video taken by my Hanmilt drone on my Patreon channel.   I have already bought a DJI Mini 4K to fly in the DR. 

My Hanmilt HK 22 Drone -- Video and a still picture

This is the beginners's drone that I was using in the Dominican Republic this past winter.  It was really great.  The hover capability was amazing -- this made it very easy to learn to fly.  If it looked like I was getting into trouble, I would just go up a bit, hover, and figure out what to do. Obviously I could not do this with a fixed wing R/C plane.  Photography was excellent. See picture below -- I took this shot from my drone this winter.  I have a video on the Patreon channel.  

I flew this thing dozens of times, and only had one crash.  It was very minor.  I am still using the original propellers. 

The brand names change on these things very quickly, and Hanmilt might not be available anymore. But there are a lot of drones like this.  I paid about $100.  

I think my next drone will be a DJI drone.  But this will have to wait until I return to the Dominican Republic in June (I am in the FAA's "No Drone Zone" around the national capital.) Here is a really interesting video on DJI: 

https://www.youtube.com/watch?v=weDjwOyZaMc&t=225s

Inspiring Stuff on "QSO Today"

Eric 4Z1UG is doing some really great interviews on his "QSO Today" podcast.   I found the last three to be especially informative and inspirational.

Chuck Adams K7QO dispensed a lot of useful information about Muppet boards and construction techniques, but more importantly he put out a lot of wisdom about the hobby, especially on the importance of teaching and sharing knowledge.

The interview with Glenn Elmore N6GN presented many interesting technical ideas, including using WSPR on VHF and UHF, and using aircraft reflections as a Sporadic-E like propagation mode.  He also mentioned "wing vortex" propagation.  Glenn talked about how to use a drone and a special light-weight transmission line to get your VHF/UHF (or cell phone) antenna above the trees.  (See above).

I found the conversation with Gerald Youngblood K5SDR both fascinating and a bit worrisome.  Gerald is obviously a great guy, and he does a wonderful job of describing the technology behind SDR radios, linking it to the phasing techniques that hams have been using since the dawn of single sideband.  He makes a strong case for the new SDR rigs, noting the absence of receiver-produced noise, the advantage of band-wide visual waterfall displays (even while noting that they tend to "make every ham an Official Observer"), and "brick wall filters that don't ring."  But I got and uneasy feeling when he referred to non-SDR rigs as "legacy rigs."  I found myself wondering how long it will be before all our rigs are required to be noise-less and all our filters skirt-less. Will there come a time when our beloved legacy rigs will be deemed unacceptable? (You can already hear this sentiment on the bands.)  And how much room is there in this SDR world for the kind of homebrewing we do? ( I know, I know.  I admit to feeling the presence of Ned Lud as I type these words.)

Great job Eric! And thanks to all the interviewees.   We look forward to the interview with Pete N6QW. 

Eric's QSO Today podcast can be found here:  http://www.qsotoday.com/

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20