Project 8: Turnstile Antenna for Weather (WX) Satellites

                           This turned out to be quite quick (about 4 hours) and easy. I used VK4LHD's construction method. The materials were under $50.

Only 8 parts

                           The aluminum tubing is cut into 6 lengths : 2 x 1200mm for the base reflectors and 4x 520mm for the top elements. These are inserted into a 40mm diameter/1000mm long pvc pipe with 1 hole drilled at 520mm  from the top and the second hole 550mm from the top and at 90 degrees to the first hole.

The 90 degree holes

                       

Bottom section

And top section done

The 4 way junction box is mounted to the top of the pipe by inserting a block into the end and screwing the junction box to it. The elements are drilled at one end to accomodate the terminals for the coax cable harness. I drilled 2 holes in the sides of the junction box to allow an access feed point for the coax.

The drilled elements

                         

The finished product

The turnstile mounted

Thats basically all there is to it. On the first pass of  NOAA 19 today, the image quality is vastly superior to any antenna i have tried before. Some more fine tuning and i should have some decent images. Here are some NOAA 18's after a bit of tinkering with WXtoIMG:

NOAA 18 26/5/2013*

NOAA 18 26/5/2013*

                                                 * Received with the RTL E4000 and SDR#                      

 

CB Days part2

                            

                              

The following year, 1979, was an exciting year for me. It started off with a few of us starting a cb radio club, and quickly grew to include most of us school mates and other teenagers from the area. We had meetings and organized get togethers, and almost nightly nets. A few years later it disbanded, as we all went seperate ways.

I purchased my first SSB rig later that year, a second hand but not very old Xtal XSSB 10-18. It was the RB-249 Australian approved 18 channel version of the 23 channel from the USA. While it didn't have a very good reputation at the time, and had very basic features, I found it a great little radio which performed excellently. Like the Fanon Fanfare182, the Xtal had the Aussie 18 with the corresponding US channels on the dial. It cost me $70, which was less than half of the new price in '79. The radio was probably the most compact SSB mobile of it's time, which I would say led to it's poor reputation, bigger obviously meant better back then. I also upgraded my antenna to a 5/8 ground plane from Tandy, and added a cheap desk microphone, a Vicom VM2. This new set up opened a new world and I made many DX contacts on SSB, and started collecting QSL cards. We had our own club printed cards to send, and a club PO Box. Sad to say, all my old cards were lost over the years. It served me very well the Xtal and never had a problem with it.
Cheers,
Mick 361.

                                          

Project 7 : AirBand Dipole

Another rainy day project! Recently, i have been making great use of my RTL Dongle with SDR# to cover the airband as well as local signals in the 118-170 MHz range. The problem: my Discone did not do a good enough job. The solution: a quick build dipole.
In keeping with spirit of this blog, i sourced the parts from an old tv antenna and a bit of pvc pipe i had left over from the multiband longwire build. The 2 elements were cut to 58cm and fed into the pipe...and thats it! Easy peasy.

The "new" Dipole mounted

SDR#

A welcome addition to my antenna family

The results are a fantastic improvement on the Discone. I'm picking up airports and aircraft  from all over the state as well as interstate. The signals are clear, particularly from the aircraft. I'm happy now that between both SDRs, i have HF and VHF Aero covered. As a test, i followed a Qantas international flight (listening on VHF) from take off, then on HF as it left our shores and ultimately tracked it using HFDL as it flew out over the Pacific.No shortage of interesting things to listen to once the cold days and nights really set in.Build time: approximately one hour.

A.M. CB Days

                              

During the height of cb popularity in the late 70's, I bought my first genuine cb radio. I had a Realistic 2 watt 3 channel walkie talkie, but in 1978 at 14 years of age I became a bona fide AM good budgie. I had been saving my paper round and pamphlet delivery money, and headed to Just CB in Mitcham (suburb of Melbourne) to purchase my first set up. The choice of cheap AM sets was endless in those days, and could be bought almost anywhere, but I decided on a cb shop to spend my money at. The Old Man was with me and he was talking to the salesman when a radio caught my eye. It was a Fanon Fanfare 182 with 18 channels on the dial, and the American channel equivalent on the inside of the Australian 18. What impressed me was the large meter, which the others didn't have, and a variable rf gain, again this feature was not on the other cheap radios. A quick run down from the salesman and I bought it, along with an Arlec power supply, coax and half wave Ringo antenna. I was a few dollars short, and my Dad put in the rest. My Dad also paid for a length of pipe and eave bracket from the local hardware to mount the antenna, and the pipe was delivered the following day.

After setting up the antenna and running the coax through the roof, with my Dad's help, I keyed up for the first time. My neighbor who lived behind us, and was a SSB cb'er, came down to AM to see where this new splatter was coming from. He soon arrived at my front door with a SWR meter and patch lead to tune the Ringo, and I was very happy for his help. Didn't help the splatter, but we both were affected the same, and had to live with it. Before long two more of my school mates had bought cb set ups that lived very close and the splatter was terrible. My poor neighbor who helped me ended up mounting his cb in his car, and was a little annoyed at us AM good budgies, but that was life on the crowded band.

They were great days and great memories. I made some new friends and spent hours on the radio after school. It was the following year that I traded in the AM for a SSB rig, more on that next time. 

Cheers,

Mick 361

DReaM and Journaline

One of the functions of the excellent free DRM program DReaM (besides digital audio) is its ability to receive Journaline - a digital service ( in this case provided by the Bureau of Meteorology ) containing weather warnings and in the example below, earthquake information for our region. In Australia, the frequency is 5954 kHz.
To begin with, HDSDR sees the DRM like this:

The initial DReaM page

The second page showing active link

The third showing a list of earthquakes

The fourth showing details of the New Britain link

 Not bad for a free program. I'm very greatful to those who take the time and make the effort to produce such a great program.

Budget RF amplifier

What do you do when you need to give that weak signal (or in this case all weak signals) a boost and want to spend no money? Well in my case, i had a handful of components, no circuit board and not much solder. I flicked through some of my old books and came across an easy design that would suit perfectly. I drew this diagram using an online designer, so its not perfect, but you get the idea.

 Component list: RESISTORS :  1 x 1.2k, 1 x 47k  CAPACITORS: 1 x 10pf  ceramic, 1 x .001uf  ceramic  DIODE: 1N4002  TRANSISTOR: NPN DS548, SWITCH x 1, BATTERY CLIP x 1 and 9V BATTERY x 1.

 The components were scavenged and i had just enough solder to roughly attach "legs" to them. They are then connected and mounted on a wood base via the same method i used as a child...screws and washers! The end result is not pretty, but signal increase from the multiband and pre-selector is fantastic.

RF amplifier working with the pre-selector

                   

Base Station 27mhz

                                                                

This is my home CB set up. A Cobra 142GTL-A, matched with a Turner +3B desk mic, real old school stuff. The Cobra was a cheap pick up for me last year, and works surprisingly well for a 35 year old radio. It's has nice clear receive and all reports on TX are good. It's on frequency and very stable with no warm up required. The only minor issue was the meter lights were not working, so I bought some blue LED's and put them behind the meters. The Turner mic cost me more than the radio, but a good investment and I get great audio reports with it. There are some Cobra 142's brought in from the USA that aren't 240 volt, so worth checking if your considering to purchase one. The 'A' in 142GTL-A shows it to be a unit designed for Australia and have a 240 volt transformer. They can also run on 12 volts and have a standard 3 pin jack on the back. Nice radio and really enjoy using it.

Cheers,

Mick 361.