Anatomy of a low frequency aviation radio beacon

Outstanding! This is one of the best antenna articles in many years and has kindled an interest in LF, if for no other reason than to experiment with antennas. In particular, the photographs prove the more 1000 words can be avoided with good photography. I’m going to pass this on to a neighbor ham interested in 630m.

 

Looks like Prees Heath on the A49 if I'm not mistaken.

 

Great article, thanks for sharing.
I'm 60 or so miles away and can hear it during the day.
Retired pilot..
73

 

NDBs are slowly disappearing from smaller airfields, as GPS takes over (until we realise that was a mistake), and the cost of replacement NDB transmitters continues to be, by one recent quote given, £30,000.

 

Quite so. My late colleague, Prof. David Last, found his retirement years full of work with eLORAN. Sadly, and perhaps rather ironically, given the topic of this discussion, David died recently when he appears likely to have suffered some medical condition whilst flying alone, resulting in a crash into the sea in North Wales.

 

No, it wasn't a bad decision.

25 years after the introduction of GPS, there were few remaining LORAN users. You can build/keep a long range navigation system, but you can't force users to buy equipment, install and maintain it. Further, in the even of a GPS outage, it would take years to produce new nav units and install them.

Thus, even if LORAN was still active, it would be a useless system in event of GPS outage.

For commercial/military usage, modern ring laser inertial systems are adequate for backup long range navigation. For CONUS I would like to see ILS remain at major airports, and a continuing widespread network of VOR-DME/TACAN for higher level navigation, e.g. above 5,000 ft. [edit]

Keep in mind that a GPS outage would constitute a national/worldwide emergency. Temporary restrictions on non-essential travel, and non-essential cargo would greatly reduce air traffic. This would compensate for lower precision and more cumbersome navigation and ATC handling.

 

Although I agree with you regarding the over reliance on GPS, I have some questions about a retired communications officer that "maintained" VOR's and weather sets, and installed ILS's. Were you enlisted? Not calling you out of anything, but an "officer", that got near any of these with a tool in hand would be redirected to something more up their alley (like a meeting or to co-ordinate something).

Thanks
Joel

 

Enlisted 16 years maintaining computers and switching systems both fixed and tactical. Officer 12 years engineering and installation, interoperability testing among the different branches, leading teams in deployed tactical environments, C-130 wing XO and <classified>.

And, yes, as an officer I've been out with my cable dogs digging ditches with a pick ax. This officer wasn't afraid to get his hands dirty while keeping an eye on the bigger picture.

 

Ok... I see... I had a cousin that was a maintenance officer and his dad thought he maintained jet engines. The discussion between us changed when I mentioned that an officer getting near an engine with a tool would probably get assaulted with it. He clarified that he mostly took care of being the judge when their was an issue on interpreting Technical Orders, and otherwise taking care of people.

Based on my experience in the 1849th E.I.S. , Usually officers were relegated to different duties (frankly we just had a team chief and an assistant, usually no more than an E-6 (and most of the team chiefs spent thier time in co-ordination), an officer NEVER helped with the instillation of an ILS or anything. Even the most motivated would just be allowed to sit quietly in the shelter during a commissioning flight inspection.

For a short time anyone in the grade of E-7 didn't require training records to show qualifications on equipment, Apparently the Air Force didn't think anyone in that grade or higher should actually work on equipment (mostly management of people and programs),

When I pointed out that I had a 3 person work-center and HAD to work on equipment, the rules changed to where a person had to be qualified and documented in their training records as to any specific task to do (I have to assume others pointed it out also).

A lot of people don't realize how much digging has to be done in the Air Force, The cable guys dig like moles. A Radar maint person that came to the Air force from the Marines said he NEVER did as much digging in the Marines (we were trying to uncover a problem that resulted in hand digging a trench about 40 feet long and six feet wide).

I have a concern with going over to only GPS, people don't realize how much work will be involved in returning to other systems if needed. Users of things don't seem to realize what goes into keeping things going (behind the scenes like it should be).

Thanks for the opportunity to war-story

Joel

 

I am sorry to report that the army signal corps is a mere shell of their former glory. They used to be the best RF guys on the planrt....now they're just IT pukes.

 

In the 938th EIS, I put together the packages after an on-site survey. I did a couple of ILS plans (along with some others such as base wide MANs, and encrypting some ground to air radios). The survey included a custom van with a complete portable ILS system and temporary antenna. Localizer's not a problem. Just point the antenna in the right direction. The glideslope is another issue. Since the RF pattern in the air has a mirror image inside the ground, whatever's in the ground is mirrored in the air. So I was there to figure out the right antenna configuration. Basically three choices: worst case, average case and best case. After best guess antenna parameters, we'd have an FAA flight check plane come and do some patterns and measurements and then tell me if I had it right or not. I batted 1000.

Then an enlisted team would go do the permanent installation.

Always glad to meet a fellow Airman! I was a special case officer. I knew things that most officers don't have a clue about, such as what an AF FM 623 is. When I was enlisted, I thought to be an officer meant you had to be something special. When I became an officer, I learned there were some pretty stupid officers. If most officers got near any hand tools, they'd give away the secret of the illusion that they're running things. The funny thing is, many TSgt's and MSgt's don't realize how much authority they have and most company grade officers don't realize how little authority they have.

When I was a SSgt and a TSgt, every officer in my chain always gave me total free reign because they knew they could count on me and if they got involved, they'd only slow me down. When I was a company grade officer, my lieutenants were almost speechless in how I interacted with my MSgt's and TSgt's because my MSgt's and TSgt's had my respect and vise-versa.

As a field grade officer, I felt like I was starting at the bottom of the food chain once again and saw first hand what starts to happen at that level. Homie wasn't going to play that game because it started to disagree with the many "oath's of office" I had raised my right hand and repeated after someone else. That's when I through in the towel and tapped out. I pulled the ejection handle.

I understand what's happening in Washington more than most people. And it was looking pretty bad there for a while recently. Now there's real hope.

As for this topic, as with everything else, what's happening with "legacy" navaides is the belief that GPS, Cell phones and internet will always be around. Most people don't realize that, yes, they're resilient, but they can also be pretty delicate. But the idiom of putting all three of these eggs in one basket applies. Some people realize this, most don't.

 

There was a LtCol ?Friedman? that was really good, he wrote a timely article called "communications in a come as you are war".

I also loved the army PM ( Preventive Mait. ) magazine that always had a sign at the end that basically said

........................................................................RIGHT NOW
........................................................................... \/
"ARE YOU WILLING TO STAKE YOUR LIFE , ON YOUR EQUIPMENT"

The "right now" part always changed the equation.

Thanks
Joel

 

The comment by @KL7AJ regarding loss of RF skills seems validated by at least a few currently active within the Army. And its gratifying how radio amateurs may be helping to bridge the knowledge and training gap. Those interested in this topic may want to click on the link highlighted below to read about it in QRZ News earlier this year,

Army Cyber Institute - HF radio can take up slack, ARS contributes

 

Great !!! Yu may be able to help me out with something. N connectors are widely considered "waterproof", but while putting in an ILS at Mchord AFB, we used a special N connector for the VHF radio that mounted on the shelter, it was about 4" long, olive drab and tapered slightly, with saddle clamps to help stay stable on the connector. I never knew if it was a special connector that was in the project package or something requested by the team chief. Any ideas (no one else has any idea what I'm talking about).

Also... I believe the Russians? are Considering a new LORAN system for when satellite navigation is denied.

https://www.c4isrnet.com/opinion/2020/04/20/russias-new-navigation-plan-reveals-a-fear-of-jamming/


Also... A few years ago the navy was starting to teach celestial navigation at the naval academy. The Air Force I think was betting on celestial nav with very sensitive staring detectors that could pick up navigationally useful stars even during broad daylight.

https://slate.com/technology/2015/1...einstates-celestial-navigation-education.html
https://www.sbir.gov/sbirsearch/detail/233828

Thanks
Joel


Thanks
Joel

 

Last summer I was showing some neighbors in Maine some objects in my telescope. One of them, a teacher at a maritime school, knew all the bright stars by name. He said they again teach celestial navigation to the students.