VE6BLD

Welcome to the CAARC web site. I have been a Ham since 1978 and am active on most modes from HF to UHF Satellite communications.


Posts by VE6BLD

Google Calendar

FOX Project Cube Sat

Reprinted from AMSAT NA
Phase 1 Fox satellites are 1-Unit CubeSats. They each include an analog FM repeater that will allow simple ground stations using an HT and an “arrow” type antenna to make contacts using the satellite. This was the mode made so popular by AO-51. The Phase 1 CubeSats also have the capability of operating in a high-speed digital mode for data communications. Two of our phase 1 Fox satellite projects have already been accepted into the NASA ELaNa program for free launches.

Preliminary Fox Keplerian Elements

We now have a launch for Fox-1 in 2014.  These Keplerian elements approximate the perigee, apogee, and inclination of the orbit.  They have been tested in several popular tracking programs, and will give a good feel for the availability and footprint to be expected.  Other details will depend on the launch site and deployment profile.

FOX-1
1 99999U 13001A   13115.03159480  .00000000  00000 0  00000 0 1    14
2 99999  64.0000 106.4735 0200000 270.0000 180.0000 14.81480000    10

With the IARU coordination received, the uplink frequency will be 435.180 MHz, and the downlink frequency will be 145.980 MHz.  For those using the SatPC32 tracking program, you can add the following line to the DOPPLER.SQF file:

FOX-1,145980,435180,FM,FM,NOR,0,0,Preliminary

We will update these as the launch approaches and more specific information becomes available.

Fox-1 Engineering Prototype.

Ham Radio on the International Space Station

The International Space Station Expedition 25 landed on Nov. 25, 2010.

Station commander Doug Wheelock gave a great tour and demonstration of the Ham Radio on board before he came home.

Testing “generic” MOSFETS for RF PA use

Testing “generic” MOSFETS for RF PA use

Earl, 4Z4TJ / VA6TJ

Low cost plastic MOSFET transistors can be used to make effective low power HF PAs.  I have an amplifier I made with IRF510’s that effectively brings a Softrock transceiver output up to legal QRP (5 W out) with a 15 volt power supply.  With that experience in mind, I started looking for plastic MOSFETs that were actually designed as RF amplifiers, and not as components in a switching power supply.

A while ago I bought some supposed RF MOSFETS on eBay from a supplier in China.  I did not take sufficient care in checking out the history of the parts that are marked MS1307 from International Rectifier.  A bit of Googling around showed that IR never made a transistor designated MS1307.

I decided that the transistors needed to be tested under actual RF amplification conditions, and not just with a multi-meter.  Therefore I build up a simple test circuit,  based on a 40m CW xmtr by VA3IUL, where I could plug in a MOSFET and test it as a 40m amplifier.   The transistor socket was taken from the wiring harness of a discarded ATX computer power supply.  The source of Q2 (tied to the emitter of Q1) needs to be grounded to obtain output – this is where the CW key would be attached, or in my case I soldered in a micro switch.

Capturebig

Capture2

Capture3big

0.5 W out into 50 ohm load through LPF (5 v/division;  10 V P-P).  Supply voltage = ~12 V

 

Initial results can be seen from the photos on the previous page.  The transistors do amplify in this circuit and I can get a nice waveform if I adjust the gate bias (R5) voltage to give a maximum 1 W output into 50 ohms.  Adjusting the bias to exceed this power level causes the scope trace to turn ugly showing that bias has shifted the transistor off the linear portion of its load-line.   What needs to be done to determine the operating limits is to vary the input level to the MOSFET gate while maintaining the bias so the transistor is operating in its range and at different supply voltages.  This is a good reason to buy a nice signal generator  J

With the simple setup shown in the schematic at a supply voltage of 13.6V, PA voltage gain as measured with the scope probe, was determined to be approximately 15 db.  Vin = 4 V P-P and Vout into 50 ohms = ~25 V P-P.

After this test, I thought about improving the impedance match into the MOSFET gate and buffering the output of the crystal oscillator.  I adapted a section of a circuit from one of my Softrock transmitters and came up with this:

This circuit did not do much to improve the waveform going into the gate of the MOSFET but it did permit higher output power with a nice sine wave after the LPF.  I could easily obtain  1.5 W out with a 13.6 V supply and a MOSFET gate bias voltage of 4.0-4.1 V (measured with open source).

 

Capture4big

 

 

I also tried reducing the bias on the oscillator transistor Q1 base by lowering the value of the base to ground resistor to about 2/3 the original value.  This did not have any noticeable effect.

 

Capture5big

 

Breadboard with the added buffer amplifier and 9:1 input transformer to the MOSFET gate

 

I do not consider this circuit to be a useable transmitter.  It’s a test jig for performing  a rudimentary check on RF MOSFETs or picking a matched pair.   As a transmitter the circuit is not appropriate: the leads are too long; there is no thermal protection in the bias, etc.  For these reasons I am not going to invest effort in testing at a higher frequency.    However, I did listen to the 7.3 MHz output (into a dummy load) on the station transceiver and, in fact, the CW sounded just fine, no key clicks, shifting notes or other QSD.

After a suitable number of cups of coffee the next morning, I realized that L1, R6 and C2 are to zero beat (pull) the crystal frequency when operating CW and are not needed for a test jig.  If you remove them, it may be necessary to increase the value of C1 .

 

 

 

Planned improvements:

  1.  Add an ammeter to be able to determine DC efficiency.
  2. Regulate the bias voltage supply.
  3. Compare RF amp results using different switching power supply transistors
  4. Determine the effect of increasing the supply voltage to 24 V.

 

I recommend checking out VA3IUL’s website http://www.qsl.net/va3iul/ where there are many circuits and ideas for projects.  Thanks to Iulian for his assistance with this little project.

 

Earl, 4Z4TJ / VA6TJ

Humpback whale foundation called Juniper Foundation

Post from Brian Davies from down under
20 m beacon
Last year I learned about the humpback whale foundation called Juniper Foundation in Hawaii. They have deployed hydrophones on “wave gliders” see link http://www.jupiterfoundation.org/projects.shtml
One of these is a beacon at 14.070
Happy New Year
Brian
 
Thanks
73 to all….+31 on xmas day we swam in the ocean morning and afternoon.

CAARC Christmas Pot Luck Supper

The CAARC Christmas Pot Luck Supper was enjoyed by approximately 35 guests on Sunday December 1. Thanks to everyone who attended and brought such good food. The following great pictures are provided by Karen VA6LDY, thanks Karen.IMG_3260IMG_3262IMG_3263IMG_3264IMG_3265IMG_3266IMG_3267IMG_3270IMG_3272

IMG_3261

IMG_3275IMG_3278IMG_3279IMG_3280IMG_3281IMG_3282IMG_3258IMG_3259IMG_3255IMG_3254IMG_3253IMG_3251

IMG_3250

IMG_3249IMG_3248

Free HandHeld winner

 

         The draw for the Free Hand Held at the Annual General meeting was won by a new ham to the Red Deer area.     Congratulations to Steve GW7GCD and we welcome him  and his wife Maria to the area.

End Fed Antenna by MOSHE INGER 4Z1PF HaGal Israel Amateur Radio Club Magazine

End Fed Antenna by MOSHE INGER 4Z1PF HaGal Israel Amateur Radio Club Magazine, issue 410, June 2013 translated by Earl VA6TJ
What more could we wish for? An easy to build antenna made from inexpensive materials, covering all
the HF bands! The simple end fed antenna described in this article meets these requirements.
A half wave end fed antenna exhibits a high impedance to the transmitter. This mis-match is too high
for most external or internal antenna tuners to deal with. However we can use a transformer to
overcome this mis-match.

Capture

 

Click this following link to download the rest of the article in PDF format

end fed antenna 4z1pf translation

Bob Heil, (video casts) with various co-hosts and guests, will cover the excitement and importance of ham radio

Bob Heil, with various co-hosts and guests, will cover the excitement and importance of ham radio – from tossing an antenna wire in a tree allowing you to talk to the world, to the importance of ham radio operators in time of disasters.

Records live every Wednesday at 6:00pm PT/9:00pm ET.  Also see drop down menu under ARTICLES.

http://twit.tv/show/ham-nation

New VE6QE Repeater Installation Time Lapse Fast

This is a video I made from 140 still images taken while Skip VE6BGT and Bob VE6BLD installed the new VE6QE Repeater and controller

  • Calendar

    January 2019

    Sun Mon Tue Wed Thu Fri Sat
    1
    2
    3
    4
    5
    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    6
    • ARES Net on the CAARC repeater system
    7
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
    8
    9
    10
    11
    12
    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    13
    • ARES Net on the CAARC repeater system
    14
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
    15
    16
    • Caarc written msg training
    17
    18
    19
    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    20
    • ARES Net on the CAARC repeater system
    21
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
    22
    23
    24
    25
    26
    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    27
    • ARES Net on the CAARC repeater system
    28
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
    29
    30
    31
    Powered by Simple Calendar