Messages

31

The RF Workbench / Re: Common and Precious IV - Construction phase

« on: September 23, 2017, 1301 UTC »

Heyho!

I've decided to test-run the setup on the local airfield, mostly hidden between trees, until spring.

Therefore... I've build a antenna post. The Antenna is mounted 4 meters above the ground. The Post itself will be stabilized by four guy wires.

Next ToDo: Finishing the TX-unit so I can fine-tuning the Antenna.

Greetings,
~Zazzle

32

The RF Workbench / Re: Common and Precious IV - Construction phase

« on: September 12, 2017, 0523 UTC »

Hey,

Zaz, this tower you speak of, is there a way you can shunt feed it as your antenna?

I could. But the mechanical setup (work and money) isn't worth the outcome.

Kind greetings,
~Zazzle

33

The RF Workbench / Re: Common and Precious IV - Concept

« on: September 11, 2017, 1422 UTC »

Heyho!

I've been thinking a bit more and let the theory face a practical approach.  Fight, fight! *ding* theory loses. :)

The split-solarmodul power supply idea doesn't work well . I ran a test with dummy loads and it happens that the upper string that feeds the main PA (which is connected in series with the lower half that charges the battery) pulls both strings down. In a way that the voltage drops to a level that makes battery charging impossible. Of course I could build some electronics to prevent that. But, eh, lets keep it simple

Another decision regards the band. The inital design was for the 80m band. I've decided against now. Three reasons. 1) 80m isn't really usable for cross continent connections. 2) It's too noisy for just 3 watts. 3) I'm not really in the mood for another long dipole. At least not now.

So, what's new?

- I've settled on the 20m band. Likely 14.750kHz.
- Power is going to be steady 3W day and night.
- The antenna will be a shortened vertical (already constructed)
- It'll be still be entirely powered by solar.
- I'm still not sure about the location. It's either going to be the metal tower far outside the city limits or old airfield nearby.

Building the Antenna was fun. I gave myself 10 bucks budget. Also, 2k Epoxy is my friend. :D

Kind greetings,
~Zazzle

34

The RF Workbench / Re: Beacon Project "Common and Precious III" (on air, 26510 kHz, 8W)

« on: August 27, 2017, 2157 UTC »

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

35

The RF Workbench / Re: Beacon Project "Common and Precious II" (on air, 6.398.5kHz, 30W)

« on: August 27, 2017, 2129 UTC »

Hey,

that was easy to fix. The sealing gave away and the recent thunderstorm with heavy rain introduced water to the circuit. Which it didn't like. The +12V track was entirely corroded away.

Fixed. The Beacon is operating again.

Kind greetings,
~Zazzle

36

The RF Workbench / Re: Beacon Project "Common and Precious III" (on air, 26510 kHz, 8W)

« on: July 24, 2017, 0756 UTC »

Hey R4002!

Thank you for pointing me to the logs. I likely never took notice of them without.


Kind greetings,
~Zazzle

37

10/11 meters / Re: Common and Precious III Beacon 26510 kHz 26.510 MHz UK SDR 1725 UTC 20 July 2017

« on: July 24, 2017, 0744 UTC »

Hi R4002!

Thank you or the report(s). I'm happy to hear that it makes it that far. It's a welcome reward for all the effort that was spend on the antenna (testing and installation).

Kind Greetings,
~Zazzle

38

The RF Workbench / Re: Beacon Project "Common and Precious II" (OFF air, 6.398.5kHz, 30W)

« on: July 17, 2017, 1153 UTC »

Hi,

Status Update: This one is off air. Since about 10 days.

It died along with the 30m band Beacon.

I took the transmitter box with me. Looks like the PA is fried. The Keying works. I suspect that the stray field of a nearby lightning strike fried it.

Kind greetings,
Zazzle

39

The RF Workbench / Re: Beacon Project "Common and Precious" (OFF air, 10.237,5kHz, 5W)

« on: July 17, 2017, 1150 UTC »

Hi,

Status Update: This one is off air. Since about 10 days.

So far I can't say why. It died along with the 40m band Beacon. Since we had some thunderstorms lately..I suspect that the stray field of a nearby lightning strike fried the PA. When standing under the Antenna can I hear a weak key'ed signal from the oscillator/driver in my mobile scanner. So I guess only the PA stage died. Soooo annoying.

Kind greetings,
Zazzle

40

The RF Workbench / Common and Precious IV - Concept

« on: June 28, 2017, 1055 UTC »

Hey,

Change of plans. I'll go with a full PWM concept for the AM transmitter. Therefore, this one is going to end up as another beacon. 20M Band. Quick and dirty.

I always wanted to build a Solar powered beacon. Now I have the chance. There's a 240W PV panel with broken glass waiting in my backyard. Also, I got hands on 6 x 12V/5Ah used (but good) Sealed Lead Acid Batteries.

The PV-Moudle is a 24V Type with a 12V/12V tap available in the junction box. One 12V block is used to charge the Batteries and run the Beacon with, lets's say 3-5W 24/7. The key is to keep operating all day long without draining the battery too much. Hence the low power when running entirely on Battery.

The other 12V half (approx 30V) goes directly to the PA. Coupled via Diode. The PA operates by Battery all the time. Except when there's enough sun. Then it operates with higher voltages, hence rising the power. 20-30W is the goal. I think this requires some hacks on the PA.

That's all for now.

~Zazzle

41

The RF Workbench / Re: Beacon Project "Common and Precious III" (on air, 26510 kHz, 8W)

« on: June 27, 2017, 0940 UTC »

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

42

The RF Workbench / Re: Beacon Project "Common and Precious" (on air, 10.237,5kHz, 5W)

« on: June 27, 2017, 0823 UTC »

Hey!

Hello! Looks like i'm able to hear Your beacon almost 24/7 on summer 
30meters, what a band

nic eto hear. Thank you for the report.

Kind greetings,
~Zazzle

43

The RF Workbench / Re: Beacon Project "Common and Precious III" (on air, 27.510kHz, 8W)

« on: June 22, 2017, 0909 UTC »

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

44

The RF Workbench / Re: Beacon Project "Common and Precious III" (on air, 27.510kHz, 8W)

« on: June 20, 2017, 2118 UTC »

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

45

The RF Workbench / Re: Beacon Project "Common and Precious IIÎ" (on air, 27.510kHz, 8W)

« on: June 19, 2017, 1225 UTC »

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


Kind greetings,
~Zazzle