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Messages - KaySeeks

Pages: [1] 2 3 ... 60
1
Equipment / Re: MW/MF beacon antennas
« on: January 21, 2020, 0212 UTC »
You are asking to tune the inductor instead of a capacitor. One way to do this inexpensively is to use what is called a "wandering lead". See the yellow wire with the alligator clip on the end of it in the photo I have linked to. Essentially you will tune the inductance by choosing the tap point on the inductor.

https://www.mfjenterprises.com/Downloads/MFJ-65/MFJ-65.jpg

2
Surely there will be no rise in monopolies because of these shenanigans.

Surely. Because unrestrained, unregulated capitalism never goes in that direction. Nah. It just doesn't happen.

3
https://www.nytimes.com/2020/01/13/us/vulture-border-protection-tower.html

Load up the tower with 50 kW MW. I wonder if that would heat them up enough to be uncomfortable?

4
Equipment / Re: Directional (Loop) Antenna for Longwave?
« on: January 18, 2020, 0856 UTC »
And with the antenna stapled to the porch, hard to turn it.

I'm visualising a house jacked up on a platform. Much simpler to rotate in that case. :D

5
ID at 0845 UTC. Very weak on an SDR in Austria but SINPO 45434 in Hungary.

6
European Pirate / Harmony 5780 AM 0840 UTC 18 January 2020
« on: January 18, 2020, 0843 UTC »
ID at 0842 UTC. SINPO 43444 in Austria.

7
the phrase "center of excellence" was used by a mega-corporation that acquired the company I worked for at the time.

COEs have largely fallen out of favour for a few years. Not really replaced with anything though. Interesting that these guys are more-or-less keeping it. Perhaps that means they are behind the times on other things too.

"Dislocation", "cost reduction", "harmonization" and "closer integration" are the new buzzwords for redundancies.

8
Still, you will need a boatload more buried radials for comparable performance to a vertical with elevated radials.

Didn't realize that this was the case. I guess I now have some reading material for the weekend!

Elevated radials might not be practical in all back garden antenna installations.

9
In my line of work, I'll worry more about the joint aches I get after spending 30 minutes at a high power am site

Probably related:

https://en.wikipedia.org/wiki/Electromagnetic_radiation_and_health#Shortwave

Quote
Shortwave (1.6 to 30 MHz) diathermy can be used as a therapeutic technique for its analgesic effect and deep muscle relaxation, but has largely been replaced by ultrasound. Temperatures in muscles can increase by 46 C, and subcutaneous fat by 15 C. The FCC has restricted the frequencies allowed for medical treatment, and most machines in the US use 27.12 MHz.[21] Shortwave diathermy can be applied in either continuous or pulsed mode. The latter came to prominence because the continuous mode produced too much heating too rapidly, making patients uncomfortable. The technique only heats tissues that are good electrical conductors, such as blood vessels and muscle. Adipose tissue (fat) receives little heating by induction fields because an electrical current is not actually going through the tissues.[22]


10
MW Free Radio / Re: Greek Pirate? 1730 AM 2156 UTC 15 Jan 2020
« on: January 16, 2020, 2200 UTC »
Pretty impressive given the distance. I'd say the music played at around 3-4 minutes in is pretty typical and confirms it to be Greek for me.

Too bad about the pulsing pumping your AGC.

11
MW Free Radio / Re: Greek Pirate? 1730 AM 2156 UTC 15 Jan 2020
« on: January 16, 2020, 2024 UTC »
Try this one near Athens for the full experience. It's usually pretty busy. It might be difficult to get one of the four listening slots during the Greek evenings. A lot of the operators use it to monitor themselves in addition to the presence of just regular listeners.

kwhighpower.ddns.net:8073/?f=1690am

12
I've long been fond of US Weather Service quality audio.

BEST AUDIO EVAH: https://www.youtube.com/watch?v=-wPeH0aQWTg

13
Tell them to hand in their iPhones and see what they say....

Take the cell phone away from your head, get away from the router above your head in the workplace, get the WiFi-equipped laptop off your lap and use sunscreen frequently before you start worrying about 5G, please.

14
The folks claiming verticals suck are the same folks that use two radials on said antenna in a suburban lot with no view of the horizon, just the neighbors plasma tv, then wonder why the match sucks and is noisy as hell.  I've had quite my fill of ham 'experts'.

+1

I like to explain the dipole/OCF vs. vertical decision as a trade off. 

A vertical is horizontal dipole turned about its centre point. Because a vertical doesn't have that other 1/4 wave leg that a dipole has up in the air, you have to compensate with radials. A lot of radials.* Otherwise, it's just not the same and you are compromising the performance of the antenna.

Some folks can't put up a dipole for one reason or another. A vertical offers the opportunity to use fewer supports to get the radiating element up in the air and this may be of value to some. However, the trade off is that you have to be prepared to put in the radials. If you have the land available, this may be an acceptable trade off.

*The more the better and the incremental benefits diminish as more are added but the data I have seen says that there is an initial barrier to entry (or barrier to reap the benefits) and that seems to be around 10-12 radials, at a minimum.

15
General Radio Discussion / Re: TDoA Questions & maybe an article?
« on: January 01, 2020, 2134 UTC »
Professional sensors can use TDOA or combinations of TDOA and other techniques to plot the source of a transmission at significant distances to very small areas.  I have used TDOA and other passive systems capable of plotting the position of a target at 10's of km to within a few meters, at hundreds of km to within a large city lot, and at thousands of km to within a few miles.

I worked on some tech that, once I was allowed to see how it worked and the results, was very surprising to me. That was the type of stuff that if I were a pirate, I might worry about. That was decades ago. Kiwi TDoA is not as good as what I was seeing then and consider that the world has moved on since then. You get the idea.


The multi transmitter solution has the most probability of success, as long as they are all the same mode.  What is that going to do to the audio though?  Propagation delays will produce echoes, even if the audio starts out in sync.

Since we are talking about potential countermeasures, here's some spew of (un)conciousness from me:

1) Perhaps one way would be to set up a triangle or polygon of low-power "confusion transmitters" in the ground wave area around the real TX, so that when they actually come near you to triangulate your exact location, there is some error introduced into the determination. Throw in some random amplitude and phase modulation onto the confusion transmitter signal. The effectiveness would greatly depend upon many variables. Think of this as "local jamming" or akin to a fighter aeroplane throwing out heat-producing chaff to confuse the infra-red detection systems of oncoming missiles. Obviously this would be wholly inappropriate for low-powered, non-HF pirates where local reception is desired.

2) Here's a real brain fart: if you could have one TX producing NVIS (Near Vertical Incidence Skywave, bouncing off the F2 layer and coming straight down) and simultaneously another TX producing a "normal" (non-vertical) skywave signal, this might introduce enough "confusion" local to the TX. However: a) finding a single frequency where  both NVIS and normal skywave work simultaneously would seem fundamentally impossible. b) It might be unpleasant for many listeners. (See Token's comments above.) Like I said, this is a brain fart.

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