ALPS VCO

In my post of June 29, I described a trial to make an oscillator which generates an EM-signal with a frequency higher than 1 GHz. The circuit, in which a BFR96 was used, did work, but the oscillator appeared to be rather unstable. Certainly not stable enough to form the core of a simple 23 cm FM  TV transmitter I want to design. Also I do not want to waste time trying to make the design stable by using frequency divider/PLL circuitry. My experience with PLL circuits is not very good.

In my search on the internet for a stable VCO, I found the ALPS 1679C at Kingcom and ordered one ( kingcom(at)chello.nl ). 

This VCO has a frequency range of 1100 - 1350 MHz. This covers the 23 cm HAM band (1240 - 1300 MHz). The VCO provides 1 mW RF output (0 dBm into 50 ohms).
I am curious to find out how this little device behaves.

50 MHz radio propagation to Morocco

A nice surprise this morning.
My 50 MHz WSPR signals reached Rabat, Morocco. Said, CN8LI, picked up my signals and vice versa I saw his signal in Holland a couple of times;

Distance was over 2200 km and I used 10 Watts, probably too much for WSPR...

This is my second best distance for the 6 meter band. A couple of weeks ago my signal was decoded in Israel (> 3000 km).

                                                               Rabat, Morocco

Improved sensitivity ADS-B receiver

With a simple dipole antenna it was easy to improve the receive results of the ADS-B receiver. I soldered two elements of about 6 cm to a coaxcable which is connected to the TVdongle. Results were great:

With DVB-T antenna; Less than 10 aircraft:

                                              DVB-T antenna (not tuned to 1090 MHz)

                                       With dipole antenna; over 30 aircraft:

Dipole with two quarter wavelength elements

Also the range is greater. I have seen aircraft near the London area 

ADS-B receiver operational

No hot solder iron required for this project. 
This morning, I have been able to capture aircraft flying above me by receiving their
ADS-B 1090 MHz signal. For this purpose the SDRsharp dongle is used. See my blog article of 7 June. All the "ins" and "outs" of ADS-B (Automatic Dependent Surveillance Broadcast) can be found on the internet. For example here: http://nl.wikipedia.org/wiki/ADS-B

I followed the intructions of the "Sterrenwacht Leeuwarden" and installed "RTL1090 beta 3" and "Globestrl" succesfully.

http://www.sterrenwachtleeuwarden.nl/adsb%20ADS-B%20luchtvaart%20radar.html

Now I can watch "real-time", without internet connection, the aircraft flying above the
western part of The Netherlands:

RTL1090 Beta3 version 

Globe-S, aircraft trajectories on July 5 abt 14:00 hr local time

On top of my PC on the righthand side you see the small antenna (which is designed for television  DVB-T reception) and the RTLsdr dongle inserted in the upper USB port 

Interesting to see how an ADS-B signal looks like in the frequency domain:

More ADS-B software: http://rtl1090.web99.de/

HG receiver in "Razzies"

"Razzies" is a magazine (in Dutch language) that is published by the radio amateurs in Zoetermeer: www.pi4raz.nl

It was good to see that my article about the "Hollands Glorie" receiver was published
in the July 2014 version of "Razzies".
You can download "Razzies" via this link: http://www.pi4raz.nl/razzies/

GHz oscillator

With a BFR96 you can make oscillators in the GHz range. With a simple setup I could generate signals up till 1.3 GHz.
I used SDRsharp as a "poor man's" spectrum analyser to view the spectrum.
Here you see the generator makes a (very unstable)  1.28 GHz signal:

Circuit diagram; I used a BFR96 (that has a transition frequency of 4.5 GHz) instead of the BFR92 (transition frequency 5 GHz). DC voltage connected to R21 is 9Vdc.

Car damage

This blog entry is not related to radio at all, but I want to share some pictures I recently made with my Canon EOS1000D. This Opel Manta suffers from minor damage. I think there is an interesting story behind the pictures that I do not know.

Besides the car pictures, I made more photoos in the recreation area Noord-Aa near Zoetermeer

Oude Meer, runway 36R Schiphol, July 3, 2014

Video test patterns

Some months ago I needed a device to generate my callsign and location on my ATV 23 cm signal. For this purpose I found and built the PicoOSD.
There is another possibility. Use a DVD player which has an USB interface and a composite video output to connect to the ATV transmitter. On a USB stick you can store video test patterns (or other pictures) and show them in a slide show for example.

With the program mentioned in the article below it is easy to generate test pictures as shown.

http://www.pi4raz.nl/index.php?option=com_content&task=view&id=356&Itemid=46

A small modification to the Telefunken DVD player makes a composite video signal available (the red wire)

Contact 17 and 19 of the SCART interface provides the composite video signal for you:

On the right hand side you see the yellow cinch plug that transports the composite video signal. I installed the cinch connector on the front of the DVD-player for easy access.

6m WSPR signal reached Israel

Today was a nice, sunny day to clean up the garden. While doing this you can still excercise the radio hobby of course. Let WSPR do the work for you. Today I selected 6m for WSPR.

This was the result:

All stations that heard my signal were from The Netherlands. Except for one; Chris, 4X1RF, from Haifa at a distance of 3250 km picked up my 10 Watt signal at 50.294 MHz.

                                                              4X, Haifa

This is definitely a record for me on 50 MHz. It is not my antenna that get the honours. That's just a simple dipole. Must have been (double-hop) Es that realized the communications link.

                                         Dutch WSPR stations encountered on 50 MHz

SDRsharp

From the website www.sdrsharp.com I installed the latest version of SDR#.
This is version v1.0.0.1285. With the previous version of SDR# I sometimes experienced a sudden stop while receiving strong signals. This anomalie seems to be solved in this version which I run on my PC with Windows7.

This beautiful program enables you, while using a cheap DVB-T dongle, to receive the radio spectrum from 50 to 1.8/2.2 GHz with a variety of modulation methods (AM, NBFM, WBFM, SSB, DSB, CW). 
In the picture above, I selected part of the 2m band. I tuned into 145.575 MHz which is the repeater output frequency of PI3UTR.

The dongles are for sale at eBay for less than $20.
For example the one I bought for $12 (incl. free shipping) has a R820T tuner with upper frequency limit of 1.8 GHz.

http://www.ebay.com/itm/RTL-SDR-FM-USB-Digital-TV-Tuner-Dongle-DVB-T-DVB-STICK-chip-RTL2832U-R820T-/281038803099?ssPageName=ADME:L:OC:NL:3160


Another example (incl. antenna and remote control for less than $10 incl. shipping)

http://www.ebay.com/itm/DVB-T-DAB-RTL2832U-R820T-25MHz-1700MHz-SDR-E4000-Upgrade-Verion-f-Win-8-7-/171327530620?pt=US_Video_Capture_TV_Tuner_Cards&hash=item27e3eaa67c


The frequency range you can receive depends on the type of tuner installed in the dongle:

R820T: 50...1800 MHz
E4000: 52...2200 MHz

I have heard/seen a lot of signals with an indoor wire of 1.5 meter connected to the dongle. For example:

=> 2m and 70cm ham radio operators
=> ADS-B aircraft transmissions at 1090 MHz
=> AM transmissions in the aircraft band around 132 MHz
=> FM broadcast stations around 100 MHz