We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Zazzle

Pages: 1 2 3 4 5 6 [7] 8 9 10 11 12 13
91
Hey,

vacation! Hoooray! I found time to etch and populate the PCB. Sadly, I added a Diode reversed which lead to a 5V TTL IC to be fed with 15V. Which it took, of course, not well. But fortuna was on my side and I found a replacement in my spareparts box.

The circuits works and will spend the next 7 days in a metall box in the basement. Burn-in test.

~Zazzle

92
Hey Josh!

Neat! It'd be sweet if you could add some telemetry to it, like ambient temp, barometric pressure, working voltage, a cheerful message, etc.

I had thoughts about that two years ago when it was in the making. I agree that those features are a nice thing. Temperature, humidity and alike. In the end I forsaw from adding such. The main reason was, that I didn't want to spend much time and money on features for a projekt that's likely to be vandalised and/or stolen/busted.

Another reason against is based on the fact, that the signal may be received with hard fading. Therfore, I like to keep it short and simple, only containing the basics.

Since the project made it almost through 1,5 years without anyone touching it, I might rethink my decision and add at least a temperature value. We'll see .:)

Kind regards,
Zazzle,



93
Hey,

Eh-hehehehe-he. That made me chuckle. I had intentions to send the Battery state (before I found an opportunity to use the local power grid) and temperature as well.

In the end I kicked those parts out because I happen to never listen to my own beacon just to know the local temperature. Also, since it's not likely that it'll be heard on a regular schedule (there are a few exceptions), it doesn't make much sense anyway. And I've to admit that I didn't want tp spend that much H/W / Construction time / software engineering time on such a feature when it's likely that the unit will be stolen/damaged/busted. I started with the basic setup and gew comfortable with it. But yes, it's a nice cool-to-have feature for sure! :)

And - oh - 120Ah Starter Battery. Your back will love you. :D

Kind regards,
~Zazzle

94
Hi there AntiRecoveryUnit,

Thank you for the report! Can you send me some additional details, like locator, via DM? I can send you a QSL-Card, in case you want one. :)

Kind greetings,
~Zazzle

95
Hi there!

so, 1,1W @ 13,8V. I Assume you need something like 150mA. That's 3,6Ah/day. Which is quite a bit. And yes, with -35C, most Batteries start to cause problems. Usually, it's just that it's not possible do draw huge current from them any longer. So 150mA shouldn't be a problem. But with ongoing discharge most electrolytes change and may freeze up.

I need to check literature (abut electrolytes and freezing points) myself before, but the best idea would likely to go with NiCd batteries.

In case you have the option to change the Battery every - say - 2 days, you could go with a starter Battery and change it before it reached a certain level of discharge. Also, you could wrapp the battery up in a LOT of thermal insulation and spend some watts on heating the Bettery itself. But with that much activity you gonna leave a trail on the ground sooner ot later. :D

PV isn't an option. How about wind? Expensive and an eyecatcher. But I wanted to mention it.

Electrician. OK. With experience when it come sto voltages above teh 1KV level? I just ask because with 20+kV even "dry wood" conducts enough to cause deady shocks and... one mistake and you're fried. Also, such "self made" installations may cause danger to other people. Insulation breakdown, whatever.

Kind regards,
~Zazzle

96
Evenin'

Update. We got a layout!

  • Bottom-Left: C Keyer
  • Left-Top: Oscillator and Keying
  • Top-Middle: FET Driver
  • Middle: PA Stage
  • Right: Impedance Matching tarnsformer and Low-Pass Filter

~Zazzle

97
QSLs Received / Re: Common and Precious QSL Card available
« on: March 09, 2016, 1311 UTC »
Hey dear board.

Sorry for all those pending QSL-Card requests. I'm digging through the backlog today. I'm also out of cards. Going to print batch #3 during the month. You'll not be forgotten. :)

Kind regards,
~Zazzle

98
Heyho,

Dunno where to start. Just let's say I discovered E-Class amplifiers by "accident" and now  I wanna play with it. But since Class-E is only fun when it comes to "more power" [Tim Taylor] I'm going to build a second "Common and Precious" CW Beacon on 40M with *gsssssp* 25W. Some may render me a bit too bold for doing that. But hey, hey, no risk no fun. And 25W sounds a lot of fun to me. :)

I was doing some engineering work with a resonant SMPS circuit when I started to wonder why it shouldn't be possible to use a pulse driven stage to generate clean HF with a proper resonant circuit on the output. Well, after checking some things with Google I stumbled upon Class-E amplifiers. Oh-yes, baby. Which basically ruined my whooole weekend 'cuz I got absorbed in technical papers and formulas.

Since it's going to be pirate equipment and may be prone to get damaged or busted, I settled with a simple setup. I left more space on the PCB for the output stage because that's what I want to tinker with.

  • The transmitter generates the operating frequency with a simple TTL-based crystal oscillator (which can be pulled a bit).
  • The last TTL-Gate is keyed by an Attiny25 which holds the morse code / identifier that's to be broadcasted.
  • The TTL Block is followed by a high-current FET-Driver.
  • The rest is obvious. A resonant circuit and just to stay clean (which is important to me) a 7-pole Low-Pass.

The whole thing end up in an small aluminium box with an external (15V/3A Notebook) PSU.

I learned from my last setup that having the transmitter high on a pole sucks rocks because I have to tear down the whole setup each time I need to work on it. This time I go with a transmitter that's hidden under the roof. 25W allow me to lose 2-3W on a long RG-58 cable so I can run the cable in a way that makes it impossible to follow easily and to a place where I can hide the transmitter without any risk of it being found by accident.

So far I got myself all the parts needes. Electronis components, wires for the antenna and poles, paint, wood slants and so on.

I think I make this happen around the easter holidays. Hope the weather works in my favor :)

Question: any reasons against f=6.553,5kHz? I wanna keep it simple and a 6.553,6kHz crystal is chep.

Kind regards,
~Zazzle

99
Good afternoon,

Oh look! Spring's ahead! It's time to quit hibernating and get active here again! No, seriously, other stuff absorbed me during Winter and I almost forgot to check this place. Sorry for all those pending QSL-Card requets. I'm digging through the backlog today.

Anway! I checked the setup last weekend after not doing so for months. I was amazed to see: it's how I left it last time. In full working condition with no damages, both in electrical and mechanical terms. Which surprised me since we experienced some nasty storms during the last couple of months.

Also, last year during the installation I had my doubts that it will even surive a month without damage (on purpose). But,well it made it's way to it's first anniversary without any damage - except a broken PSU. But that doesn't count.

Hooray, I guess. :)

Kind greetings, Zazzle.


100
The RF Workbench / Re: Ten Minute Transmitter
« on: March 09, 2016, 0946 UTC »
Hey makeRF,

those simple circuits are fun to begin with because they work almost every time on the first try and one gets a feeling of success (and therefore motivation). Since you have a Scope capable of FFT analysis, I think there's no need to point that out: but please have an eye on the RFI emitted.  I had saw simple 40m band oscillators that easily managed to generate harmonics on 100Mhz and more due to parasitive capacitive couple between (too long) component legs (primary because the transistor choosen was a type with ft=450Mhz++). So, wehen using a simple Oscilattor it's ueful to install a low-pass on it's output.

Oh, and, mind:
- When building an oscillator: it will amplify like hell, but hardly oscillate.
- When building an amplifier, it will oscillate perfectly but hardly amplify. :)

Kind regards,
Zazzle.

101
HF Beacons / Re: Common and Precious 10237.77 Khz cw
« on: October 30, 2015, 0848 UTC »
Hey everyone!

(oooof, work got me hard - again - after my last vacation... Soryr for teh slow reply.)

I copied today the beacon "Common amd Precious" 18 oct. 2015 at 13.45 UTC
The signal was very low.
What is it for?

Thank you for the report/PN!
Well, the shortest and most honest answer: for the joy and fun of it. :)


just now (23-Oct-2015 // 10.30z) I could copy that beacon (from JO62SK, Berlin Region/Germany) with a good signal RST 569 (on my DX-88 outdoor vertical) again - my location JO41WM. On my back-up 10m longwire antenna (3m AGL) it is even RST 579. Anotjher nice lunch break ;-) Hope I can get any QSL ;-)
[/quote

Of course! I send it away some days ago and I believe you got it already. Enjoy. :)

Kind regards,
Zazzle

102
HF Beacons / Re: 40M QSL Contest (2-4. October 2015)
« on: October 02, 2015, 1203 UTC »
Hey everyone.

It's on air. 6987kHz. Go for it. :)

~Zazzle

103
HF Beacons / 40M QSL Contest (2-4. October 2015)
« on: September 24, 2015, 1253 UTC »
Hey everyone! :)

If nothing f***s up my schedule, this is gonna happen! (Feel free to move this post if it doesn't fit here.)

I'm heading to the other side of the Country at the beginning of October. Small vacation, you know.  The other side, that means: lots of high mountains with no people around for miles. I'll take a 10W 40m Beacon with me. And 100Ah Car Battery (oh, the pain. My back is screaming already. But no pain, no 'gain' - Bad pun intended ;p))

So! Here's the deal: try to tune in and if you succeed: send me a REPORT VIA PM on this board. As usual, you'll be rewarded with a special edition high quality QSL card for free. :)

X-Tra points for providing an audio record.

Summary:
  • Start: 2. of October, 12:00 UTC
  • End: 4. of October, 12:00 UTC
  • Frequency: To be announced (somewhat between 6.950kHz and 6.990kHz
  • RIG used: 10W CW + half have Dipole.
  • Key to get a QSL-Card: the Name and Locator of the Beacon.

(Please; if you post your report public on the board: forsee from adding Name/Locator. You can do yo after the contest is over.)

Greetings,
Zazzle

104
The RF Workbench / Re: Beacon Project #2 (on a Tower) - Introduction
« on: September 17, 2015, 0828 UTC »
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

105
The RF Workbench / Re: thinking of making the leap from FM to SW
« on: September 17, 2015, 0815 UTC »
Hi there jackson_r!

Avoding 'the knock' is always a thing thinking about. ;)

Quote
"daddy, what are you doing" in the background while I was trying to live broadcast wouldn't work so well.  

Aww! I love kids. That'd be fun! :)

Audio-Output 2 MIC: Naa, that's no rocket science. Maybe ask for help with the soldering in your circle of friends or relatives? Help ist just around the corner most times. Without reading the manual for the baby you have your eyes on: usually it takes two modifications:
  • Bridge teh PTT switch so it's broacasting permamently.
  • Adapt the voltage level of the headphone out to the MIC input. That's usually 2V to 2mV. That can be done by a simple resistor based voltage divider. In case you keep on your actaual plan and need some help with the valkues: poke me.

About the Solar-Power thingie: If you're not happen to live somewhere with a LOT of sunshine all day long (like in a country/state around the equator) that can be tricky. I hate to ruin the fun but it won't work in areas with something called "winter" and "snow" around.

Basic calculation: We assume you whole rig (with 5W PO) consumes about 1,5A. For one day that's 25h*1,5A = 36Ah. That the entire charge of a full standard (small) car battery.

A standard value for solar charging estimates (during summer) 5 sunhours (with full power) per day. 36Ah / 5h = 7,2A. That's a 180W (+) PV Panel. The dimensions for such are approx 1x1.7m. About 150 bucks (ebay). And it won't be easy to hide.

And this goes for perfect conditions. Rainy day? Forget it. You're out of power. We still assume you have nothing called "winter" in your area I'd say you've to go for 300+W PV power to provide a stable charge into a (at least 88Ah) battery.

(those are all quick'n'dirty calculations. Doing a proper evaulations that ensure a reiable power supply will be way more complex. I forsee from that for now.)

Also, a car battery will wear down within one year (or less). They're not made for full swing (dis-)charge cycles. You can, of course, go for a special battery made for solar operation. But, eh, expensive. 75Ah is about 250 Bucks.

Other sidenotes: keep an eye on the specs of the Radio. Is it made for long term key-down operation? Also, when putting it outside: spend some thought on the ambient temperature. In case sun hits the box the ambient temperature can easily exceed 60+C. The device temperature adds to it. 90C isn't unlikely.

Greetings,
~Zazzle

Pages: 1 2 3 4 5 6 [7] 8 9 10 11 12 13