HFU HF Underground
Technical Topics => The RF Workbench => Topic started by: Zazzle on May 19, 2015, 1132 UTC
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Hi everyone,
So, as a HF addict I need my next drug shoot aka "HF project" :). It's going to be a beacon again.
I felt for doing some urban exploring lately which made me visit an old industrial complex not that far away from home. The are several smaller towers on the areal and two big chimneys. I did some climbing. WOA! That would be the perfect location for a Beacon Transmitter. I mean... 80m above the ground and no big city close by. F#ck, yes!
The smaller towers are easy to climb on. The plattform offers many option for installing Antennas. The tower itself is about 50 meters
The chimney is... a challenge to climb on. Exhausting. Getting stuff up there is even more of a challenge. But, my god, what an awesome place for a Beacon. Sadly, there's a metal tube comming from the chimney which is even longer than the platform and may interfer with possible Antennas. Also, it's too risky I think.
So, for reasons of security, accessibility for maintenance and an obstacle free Antenna environment I will go for the smaller tower. The only bad side is: other people might be tempted to climb on it. Less than on the chimney.
I need your opinions now, because I've a hard time making a decision. It's about possible signal propagation and use of Antennas.
Frequency 1 - 10M Band
Pros
- I have an old 5/8λ CB beam at home. It's easy to install and it's also relatively broadbanded. Therefore, the SWR should be not an issue.
- I could also use a 1/2λ inverted V. Each side would be about 2,60m. That's managable.
Cons
- The propagation isn't the best and DX connections are rare.
- There's not really much activity when it comes to pirate radio/beacons.
Frequency 2 - 40M Band
Pros
- Awesome propagaion, also during daytime.
- Many pirate activities just below the offical HAM-Bands
Cons
- A huge antenna is needed. A Dipole is not an option. I think I could build a KGD (http://www.i1wqrlinkradio.com/antype/ch22/chiave668.htm). But this sort of antenna has a very small bandwith and the SWR matching is tricy because it's sensitive to the objects around.
I think a good working Antenna in combination with less potential contacts is still better than a bad Antenna with more possible contacts?
Your opinion? :)
Greetings,
~Zazzle
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Mornin',
Made my mind. I'm going with the version on 40m. I'm curious about the KGD Antenna. So, jep, gonna build that one :)
Kind regards,
~Zazzle
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Hi there!
It has begun. After working on the circuit every now and then I placed the parts order yesterday. During the next couple of weeks I'm going to build the Transmitter unit and Antenna.
I did a lot of rethinking. A decision that took extremly long was about the final Band/Frequency. Despite my previous opinion, I settled on the 10m Band now. Instead of just going by theory only I did some Band monitoring almost every day. Despite the fact, that the propagation for long jumps is overall quite bad on 10M, it comes with a lot of advantages: when the Band is open, pretty neat jumps can be archived. It's quite quite. Not a lot of noise, so even a small signal stands out against the noise floor.
Another argument that made me settle on 10m was the Antenna size. I still want to install the whole system (Solar powered this time) on the industrial chimey (shown on the picture in my previous post). I expect a LOT of heavy wind up there and therefore mechanical stress.
Actually, I'm still not sure about the Antenna. Two types are already out of question:
- I have a CB Antenna "Hurricane" flying around. After reading reviews I better throw it away.
- A friend has an 5/8λ Vertical from his CB-Age. But I doubt that this long monster will even survive the first storm up there.
Let's discuss that in a different topic (http://www.hfunderground.com/board/index.php/topic,22617.0.html). :)
So far, those are the features/ideas
- Approx 1,3W.
- Solar powered by an 50W solar module. Wayyy overdone during summer time but likey still not powerful enough during winter time.
- Uses 3 seperate 1.300mAh Ni-Mh Battery packs in parallel. In case one Battery pack fails the system won't die.
- Water proof IP67 heavy duty Plastic housing, holding the charger unit, Battery pack and TX-Unit.
Kind regards,
~Zazzle
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Hey
Progress! I've etched the PCB and populated it almost entirely (most inductors are still missining). In fact I'd build two identical boards. One for the final setup and one for experiments (so I don't ruin the primary board like I almost did with the 30m one.).
Also, I wanted to play a bit with a Frequency Doubler Circuit. Just becasue I haven't for a while. The Frequency I'm gonna use is 27.215,00kHz (so I use a 13.605,5kHz X-tal) , which is basically CH #21 on the CB Band. Due to the Signal propagation behaviour I won't molest many people. Ch #21 is devasted around here. Haben't heard anyone on it during the last 3 weeks. Also, chances are good that it may be heard because it's a knows used/frequency.
From the left to the right: Oscillator, Frequency Doubler (and Buffer), PA Stage and Filter. The PO will be around 1.1W. One Vari-Cap is to pull the X-Tal and the second tunes the Inductor for the Frequency Doubler into resonance.
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How did you etch the board? Looks pretty good.
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From the left to the right: Oscillator, Frequency Doubler (and Buffer), PA Stage and Filter. The PO will be around 1.1W. One Vari-Cap is to pull the X-Tal and the second tunes the Inductor for the Frequency Doubler into resonance.
(http://aintnogod.com/ipb/uploads/gallery/album_17/gallery_298_17_1836.gif)
How did you etch the board? Looks pretty good.
I would like to know it also ;D
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Hey skeezix!
How did you etch the board? Looks pretty good.
It was done the old fasioned way by using a photo active PCB material and Ferric Chloride Etchant.
The layout was done in Eagly Professional by hand. Since I didn't want to do a through-hole board but a SMD-like surface mounted one (easier for debugging and testing). I put the components from the library into their final position and started routing the conducting paths by hand (with the "draw rectangle" function).
I'm not satified with the job. The board turned out too dense (I'm used building high density PCBs and the big screen fooled me). It's a big ugly to solder and I hope I won't end up with oscillation due to too little component spacing.)
But: thanks a lot! :)
Greetings,
~Zazzle
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The best reception I've had with 10 meters is late afternoons / early evenings, usually during fall and spring.
I also had good results with a single quad loop antenna on a short pole only ten-fifteen feet off the ground. It worked amazingly well on 11 meter SSB, also received 10 meters and VHF low band very well.
So don't rule that out as a backup for the antenna you're mounting on the pole.
Probably wouldn't work on a high tower because a quad loop is sort of like a kite when in the wind.
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^^^^^^^
I think I either put this reply into the wrong thread by accident, or it sort of was shifted.
It was intended for another thread about 10 meter propagation and 10 meter antennas.
Sorry for the confusion.
Boombox
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Hey,
heh, I was already wondering about it. No worries. :)
~Zazzle.
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So!
Progress. A little. Mostly theory.
I made my mind and likely won't put up the solar powered beacon soon. There's just no use in hurrying things and face problems later. I had several problems with the H/W of the 30m beacon. The second will be ~35km away from home and on a huge tower. I have no desire to go up and down again and again.
I've build two trnsmitter boards in advance. One for debugging and one for operation. That leaves me with the opportunity to get one on air while having the second device for debugging at home.
So! I made my mind and came to teh conclusion that I'm going to install the 10m test beacon on the same roof as the 30m one. Since I have grid up there I'm also gonna add a 5W PA (which I happen to have flying around ;p).
I think at the end of the month I have it on air. Now I'm still left with the question about it's name. I ponder about such like "The Ugly", "Wild and Free". Open for suggestions!
~Zazzle
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Funny how this hobby, in your case and maybe others', has crossed roads a bit with Urban Exploration - something I have dabbled in from time to time. Fun stuff. Do no harm, take pictures, leave only footprints. :)
Meantime, I tried to pick up the 30m beacon last night on my R-5000 with no luck but I live in a radio-noisy area between New York and Philadelphia. I also have some noise reduction work to do around the house.
I look forward to hearing your 30m signal at some point and wish you luck on your 10m adventure.
Mike
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Heyho!
Had a look at the project yesterday and started working on it again. Found a mistake I made in the circuit note - and of course I've build the circuit that way. Let's see whether fixing it brings the project on track again.
Also, I made my mind about the tower thingie. No Tower. To far away and to annoying in case I've to fix stuff. I'm going to install the project on the old air field close by (which is a nature park so no one will run over the area which means it's pretty safe from being damaged by idiots).
Also, I'm gonna make this one finally all Solar powered. A friend of mine gave me several 12V/7Ah Lead Acid Batteries whichcome with at least 60% of remaining capacity. I'm gonna glue and connect them in parallel. Nice batter ypack for fee. Also, I got a broken (front glass) 240W PV panel that still outputs ~150W.
I've calculated that I need about 2,7Ah per day. Works fine with a 150W panel. Also during winter.
Since I'm gonna use the 10M Band I could also stpp broadcasting during night.
Anyway, I keep you updated. :)
~Zazzle
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Zaz, if it's going to be on a tower, is there any way you could shunt feed the tower itself as your antenna?
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Hey Josh!
Zaz, if it's going to be on a tower, is there any way you could shunt feed the tower itself as your antenna?
I decided against. Too far away. It's always a 60km trip when I want to try something. Also, for 10m there's a lot of small and effective antennas. Hell, even a dipole is small and can be done with stable steel rods. :)
But I had ideas about shunt feed the tower before. Once, I had some half-drunk discussion with a friend and we were joking about feeding that tower on the 80m band with 100W.
There's a sketch we did back then (see it attached).
But after I read literature about I had serious doubts. Literature says that impedance matching is tricky.
What's your experience with that? I'm quite interested in this kind of antenna. :)
Kind greetings,
Zazzle
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On the shunt feeding and so on, I'd just use a tuner or discrete components and feed it anywhere it was doable. On a HAM tower setup, some guys run a wire down from a yardarm up the tower, with the wire grounded to the tower up at the yardarm, then feed the wire at the bottom so you end up with a linearly loaded vertical.
Here's some related info;
http://earthsignals.com/N6TZ/
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Hey there,
I picked the project from the shelf last weekend and had a look at it. Eh. I dumped the board and started anew on a DIY epo-board.
After I spend quite some time on reading hard theory on frequency multiplication during my recent holidays I decided to go with a different approach.
I also settled on the frequency I'm gonna use. Found an x-tal with 13.612.500kHz in my junkpile. Makes 27.225.000kHz (CB Channel 22) in the end. I go with that. Since the output power will be approx 1,5W it won't cause local issues. Especially since it'll not operate near to homes.
I'll attach a picture when I turned the test-thingie into a nice board. :)
Kind greetings,
~Zazzle
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Hey,
I had some fun during the last evenings. And leaned quite a lot about signal multiplication and filtering. I also learned that SPICE-Simulations are b*tches, even when using non-perfect components in regard to RF-stuff. But anyway! The current circuit outputs a perfect Sine-wave with approx 1,3W. Some short caculations on paper show that I should eable to boost the power to approx 5-6W with proper stage matching. Well, let's see what the real stuff says to that.
Kind greetings,
~Zazzle
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Hey,
<Note: I changed the projekt title>
It's funny how projects change while they're being build. I intended to go with 500mW because that works well on 11m. Now I'm stuck with 8W. Opsie~. How could that eeeeeeeeeeever happen.
Btw: I'm a bit embarrassed to share the pictures attached. That's the most ugly thing I've ever build when it come sto RF. But the board has that lovely oldschool "RF from scratch"-look. :)
Well, I somehow wanted to play a bit with impedance matching between stages and what's the best way to drive a class C amp from a class A stage. I guess I accomplished the mission. The circuit runs stable from 8-16V and from -30°C to 80°C. Of course the power drops a bit when the unit heats up. From 8W to 6W. But the circuit stays stable, the effiency is OK and the output signal always clean and strong.
What's still missing is some components around the ATTINY25. And, of course, the µC itself.
I've found an old 5/8 CB Antenna in the basement. That'll go through a modification.
I still ponder the frequency to use...
- 27.185kHz (EU-Wide CB Channel #19)
- 26.510kHz (Allocated to some CB Channel only in Poland)
Your opinion on that?
I guess I'll go with 26.510kHz. Less chances of pissing someone off who'll file a complain that leads to investigations. :)
(Well, and given that I'm from Germany... I guess I should follow tradition and invade Poland. ;p [J/K!!])
Kind greeting,
Zazzle
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So!
26.510kHz it is!
I'm done here. Now... hello Antenna!
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Hi!
I found time to build a L-Match for the old CB Antenna I'm gonna use with this Beacon. Works like a charm. SWR 1:1,2 or better.
By now it's mounted on "the roof"[TM]. But I forgot the Transmitter unit at home. Well, that has to wait until next weekend then.
Greetings,
Zazzle
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Oh, well. Sometimes I'm an idiot.
We had some sunny days recently, which left me with enough motivation to install this Beacon. Only to discover, that the SWR is beyond anything I'd call reasonable. I assumed it was, as usual, the metal construction of the roof that caused it. Adjusting the matching circuit didn't help. I was clueless for some minutes until it struck me. To make sure the matching circuit in the foot of the antenna won't become lose due to vibrations of the antenna (introduced by the wind) I've filled the coil with epoxy. Thus, making sure it's permanently attached to the socket. I should have thought about the fact that the material, a coil is wound on, even if it's a non conductive material, affects the inductance. So, well, yeah. The Epoxy filling affected the matching circuit enough to make it unusable.
Well. Do it again, Sam. Looks like I've to build and install a new coil.
Greezings,
Zazzle
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Hi everyone,
This one is up - finally.
The recent warm weather provided enough motivation to sit in the garden and work a bit on a new antenna match.
The old one existed (like shown on the photo in the post above) on an inductor and variable C. Basically a Pi-Match with the upper coil part providing an inductive reactance to cancel out the capacitive reactance of the (too short) antenna. But the resonant circuit has proven itself to be too sensitive to a changing surrounding which affect the impedance of the beam.
Therfore, I did some theory and settled on a UNUN (transforming the feedpoint impedance of ~30R tu 50R) with some additional inductive overhead to compensate the capacitive part of the beam itself.
The whole thing can be adjusted by pushing and pulling the winding together or apart. I was able to adjust the SWR on roof to approx 1:1.05 within less than a minute. Which felt sooo good. :)
Installing was easy. I got everything prepared at home and on the roof all party just fell into place.
Back at home I was a bit worried about the radiation angle. I was able to receive the beacon at home with a simple hand scanner and S5. Made me worry that the antenna doesn't work well for DX broadcasting but got a flat, strong local field.
The first thing I did today morning was to check the "local" WebSDRs around (here in Europe) and I was rewarded with a good reception in England (a little less than 1.100km). Nice. Felt awesome to know that the DX-Field works well.
I guess I'm happy how this turned out. :)
I also made good use of my motivation as long as it's still present and wrote a small documentation about the project in the wiki.
Common and Precious Wiki Entry (https://www.hfunderground.com/wiki/Common_and_Precious_3)
Kind greetings,
~Zazzle
(https://www.hfunderground.com/w/images/f/f1/11M-CaP-Antenna-Matching.jpg)
(https://www.hfunderground.com/w/images/9/9d/11M-CaP-Pole-Antenna-Sidelook.jpg)
(https://www.hfunderground.com/w/images/1/17/CaP-Chester-Cheshire-UK-WebSDR-19.06.2017.jpg)
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Hi Zazz, I noted some typos in your wiki;
singla = signal
smoth = smooth
ferrit = ferrite
(tripple) = (triple)
collecor = collector
thefore = therefore
it's it's = its
ferrit = ferrite
Ops, this escallated = Oops, this escalated
escallated = escalated
Can't help it, the editor in me came out. Really nice beacon you have there, the board and parts are elegantly arranged.
:D
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Hey,
Can't help it, the editor in me came out. Really nice beacon you have there, the board and parts are elegantly arranged.
Appreciated! Thank you!
Btw: your HFU login also works for the wiki. :)
Kind Greetings,
~Zazzle
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Maybe change the subject of this message thread to indicate the frequency is 26.510 kHz, not 27.510 MHz?
BTW I have not heard you on this frequency yet, but I heard the 48 and 30 meter beacons the other evening. Propagation on 11m has not been great here recently.
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Hey Chris!
Maybe change the subject of this message thread to indicate the frequency is 26.510 kHz, not 27.510 MHz?
Oh. My bad. Thanks for telling. :)
Btw: what's the proper notation (when it comes to 1000er separation) in the US (or this board)? In Germany we do it like 1.500.000,00Hz for 1,5MHz
BTW I have not heard you on this frequency yet, but I heard the 48 and 30 meter beacons the other evening. Propagation on 11m has not been great here recently.
Tricky, I think. Since the 11M band is only day-active (including sunset) it'll be a small window that also requires proper condition just in the right moment. Nevertheless. I'm curious whether it'll make it over the lake. :)
Kind greetings,
Zazzle
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26510 kHz would be correct here in the US, I changed the subject for you.
I have not been hearing any 11m DX from Europe so far this year, so it may not be possible, but I will check now and then.
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How hard would it be to make it active during dawn to dusk?
And if so would there be any benefit?
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Common and Precious III has been received in Kyiv between 1545 and 1615 UTC with SINPO=35433-45433. RX: RTL SDR DVB-T Dongle (RTL2832U+R820T), ANT: 10 m wire.
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The beacon is active at the moment! And I have it's signal again here.
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Hi!
26510 kHz would be correct here in the US, I changed the subject for you.
Thank you!
The beacon is active at the moment! And I have it's signal again here.
Thank you for reporting. Nice to know that it's working properly. :)
Kind greetings,
Zazzle
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I checked three different KiwiSDRs (one in the UK, two in different parts of Russia) and was able to hear Common and Precious III on 26510 kHz / 26.510 MHz around 1720-1740 UTC on July 20th, 2017. Keep up the good work, Zazzle!
See the logs:
https://www.hfunderground.com/board/index.php/topic,36222.0.html (https://www.hfunderground.com/board/index.php/topic,36222.0.html)
https://www.hfunderground.com/board/index.php/topic,36224.0.html (https://www.hfunderground.com/board/index.php/topic,36224.0.html)
https://www.hfunderground.com/board/index.php/topic,36225.0.html (https://www.hfunderground.com/board/index.php/topic,36225.0.html)
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Hey R4002!
Thank you for pointing me to the logs. I likely never took notice of them without. :)
Kind greetings,
~Zazzle
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Hey,
Rodents really like my mains wires. This time I found one of the wires cut and with bitemarks on the insulation. I guess it happened approx 14 days ago. So, yeah, this one had a downtime as well. But it's up again by now.
Kind greetings,
~Zazzle
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Hey,
Offline right now. Storm damage.
We had two heavy storms recently. One managed to break the 5/8 clean in half.
Oh well, hello quick and dirty fix. I know... Copper on Alu isn't the best thing but... eh.. it'll do for a while. Too cold in the dark hours for complicated tasks.
Kind greezings,
~Zazzle
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Heyho,
the beacon is up again.
Also, I might delay other repair works for now. Winter is knocking at the door. The weather was stormy today and the temperature went up/down all day long. Despite the fact that the weather report forcasted positive degrees... it was wrong and we're below the freezing point now.
When standing on the roof I took notice of some odd white stuff on it. Oh. Patches of frozen water. Actually, I felt for turning and going back home. But given that I had my pockets full of tools and stuff to fix the antenna (and tune it properly again)... I decided to go on. Turned out that the grip on the roof was still okay. But I won't do that again with freezing temperatures. Not worth the risk.
Fixing everything went smooth and - despite my expectation - I managed to finish everything within half and hour and before I started to feel cold. I took the antenna analyzer with me. SWR is 1.07 (with 51.6R feedpoint impedance, X is below 2R).
Also, this night full of small adventures was another one to memorise. Sometimes it happens that the atmosphere and feeling is just right. I always get into this specific deeply content and slightly longing (not in a bad way) mood then.
Just standing in the middle of the roof, the antenna rising into the canopy of stars above like a finger reaching out, sending its message quiet and unnoticed. Hear me. Find me. Love me. Watching the stars, feeing their soothing shine that makes me feel at home and lost at the same. Hearing the wind whispering in the leaves, tempting them to fall. Thoughs wandering, maybe to such silly though and questions like whether there's actually such a thing like werewolfes that run the forest at night. And whether they're really bloodthirsty things or just human being that are scared out of mind while they go to the burden this transistion with each lunar circle anew.
Fun fact: If I was granted to change my form for one night I'd definitely go for a fox on two legs. Kinda were-fox, you know? But a kind one, no one that seeks blood. Big proud ears, all black on the back. A thick, fluffy rusty red winter coat to keep warm. Bright amber eyes and a nose to match those keen eyes. Not to forget those big black paws to walk on, with soft pads on the sole that allow me to feel the soil I walk on.
I love the mood such night-outs get me in. Oh well, or it's my brain being half frozen from being up on the roof. Or me lacking badly of sleep.
In anyway - kind greetings,
~Zazzle (in human shape right now)
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https://ixquick-proxy.com/do/spg/show_picture.pl?l=english&rais=1&oiu=https%3A%2F%2Fwww.maykool.com%2Fmedia%2Fcatalog%2Fproduct%2Fcache%2F1%2Fimage%2F600x900%2F9df78eab33525d08d6e5fb8d27136e95%2Ff%2Fu%2Ffurry-fox-halloween-costume-022157.jpg&sp=7b4b63113214b175cb234d1d1f3e7576
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*blinks*
I guess I'm slowly waking up from hibernation. It's still cold but not slippery (one the roof) anymore (so far). The new season is about to start and I got some new ideas.
Anyway, seem like someone's playing cat and mouse with me. The Beacon was down for - dunno - 6-9 weeks or so?
Remember that I got problems with a wire gnawed by a rat or so? In retrospective, it's more likely that someone tried to cut it with a blunt knife.
When I was checking for the reason of the deceased operation I found this:
- Out of three pairs of wires exactly the feeding couple was ripped out of the terminal.
- Also, the cable that runs under the roof (!) which I patched last year had one side ripped out of the terminal. I really wonder how someone managed to get under the roof. Except with exhausting climbing actions (which I had to conduct to fix the connection).
I wonder what this is all about. Maybe it's some kids having fun. Or someone's doing this with a rason. I wonder what the reason might be then. In any case, I grew suspicious and very careful. Maybe I'm gonna move everything eventually.
Anway, this one's up again. I wonder what (and when) will be next.
Greetings,
Zazzle.
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Beacon received today 09june2018 at 19,00 CET 26510KHz from Italy JN63KV
https://soundcloud.com/massimo-martini-985500288/sdrsharp-20180609-162206z-26509000hz-af
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Hi,
so yeah... after all those years the first serious issue. The Antenna got stolen and some wire-cutting done.
Once more the whole issue doesn't really makes sense when it comes to understanding it. The Antenna got removed WITH its short wooden pole. The wooden pole itself was mounted with U-clamps. The Antenna was bolted to the wooden pole with standard screws. So, someone took Antenna + pole. Why the pole as well? All radials got cut clean of. The ground wire as well. The Antenna cable got cut approx half a meter away from the transmitter box.
In addition, the power cable to the socket (in which the PSU was plugged in) got cut. The transmitter itself was left alone.
The whole setup of Cap 2 (self build Dipole) some meters away was left alone and is still OK (went off air as well because the power cable leading to it was looped through the socket for this beacon).
To make the whole issue even more odd... the cable that runs under the roof (required climb the metal construction for that) got cut as well. Eh...
So what is this about?
- Most likely someone stealing the CB Antenna. (Have fun trying to tune it to the CB-Bands... won't work. :D)
- FCC? No way. They'd taken everything along.
- Someone else wanting to shut down my beacons? Why just (really clean and neat) uninstall the antenna and not break all setups and take the transmitters along?
- Why cutting the cable under the roof (again... I had cut cables at different points three times by now...)
I stick to Occam's razor. The Antenna was of interest. Everything else doesn't make any sense without further information.
Gonna think a bit about what to do now. So far I took all transmitter units along. Doing maintainance and finally fixing the swapped numbers in the morse code of CaP 2 (sends 52W instead of 25W).
Since the whole area might be torn down sooner or later... gets me pondering whether to get it back on air or find another location. Also, might not give away the location through locator again.
Questions over questions.
(But to mention something positive: had a young fox - likely born last year - following me bit with curious looks. Handsome lad. But I better not get started on foxes again or I get counter-posted with kinky lady-fox costumes once more. ;p )
So long...
Zazzle
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Thanks for the update zazzle. I think your analysis is correct. I would certainly agree with not broadcasting the location. A mo e of lovation seems wise also. Thank you for maintaining this weekend . It's really only chance we in the US to Log a European beacon.
Also super interesting to read off your photojournalism documenting both your beacons construction and placement . Please keep up the good work