Monday 29 July 2013

Project 11: Better quality 150MHz Dipole

                       This is essentially an upgrade of project 7 Airband Dipole . I thought the results from that roughly built, simple,"thrown together" Dipole were encouraging enough to build something more permanent. Once again, the materials were cheap : a 3 way junction box, 1 metre length of aluminium tubing, 8 cm of old nylex garden hose and silicon sealant.
Hose sections used as packing
                       The tubing came as  1 m length so i cut that in half. The tubing does not fit snugly into the "T-piece" so some packing is required. In this case, 2 bits of old garden hose cut into 4 cm sections and then cut down the middle, opened up and pushed onto the tubing which then fits nicely into the box. The bits of excess hose are then trimmed off.

Packing trimmed and holed drilled
                       After that, the holes are drilled for the coax fittings. The standard nuts, bolts, washers and auto-electric crimped type connectors are used. The box cover plate is screwed back on, and silicon sealant is applied just about everywhere.
co-ax fitted

cover replaced
                       Once that had cured, it was mounted in place of my weather station which despite being guaranteed to be made of U.V. resistant plastic, is falling to pieces after 5 years in the aussie sun. This time the antenna is mounted a wave length away from the mast which i noticed is the practice used on commercial VHF antennas.
                       Unsurprisingly, this gem of an antenna performs far better than its predecessor. I have really enjoyed the progress of these 2 builds. It started as in idea i saw on the web, then to a rough prototype for proof of concept and now the final build. A very simple, top performing antenna build, enjoyable from start to finish.



Tuesday 23 July 2013

Leson TW232 and Turner +3b

These two desk microphones would be the best and most well known CB Radio microphones ever made, and are still sought after today. I am fortunate that I own a fine working example of each.

I purchased both from Ebay and while the Turner was at expected price, $90 plus postage, I got the Leson for a bargain at $30 plus postage. The Turner is in excellent condition with very few signs of it's age, and I prefer this mic for the slightly better audio quality reports I receive. The Leson is a quality mic too and works perfectly, although it has some scratches and wear marks. The audio is classic Leson with that slightly tinnie sound, and can be picked on air easily by other operators. As with nearly all Leson's, the battery door is missing as they were flimsy and broke easy. The battery fit is snug, but does tend to fall out when the mic is moved, so a bit of blue tack keeps the battery in place nicely.

If you can get hold of one of these two classic mic's, you wont be disappointed and will add some class and nostalgia to your station. Check to make sure the lock down switch is there if your looking at a Leson, as they tended to break with a heavy handed user.

Mick 361.

Tuesday 16 July 2013

My antenna far

          Thought i would post some pics of my antenna setup to date.
My steadily growing collection of antennas

A closer view with the wx sat just out of shot
         From left to right : 1) The ADSB collinear (top)
                                     2) The OCF Windom (bottom)
                                     3) Sat dish
                                     4) Station Master (top)
                                     5) Discone (mid left)
                                     6) Air band Dipole
                                     7) UHF Collinear (top)
                                     8) and 9) 2 x longwires covering NTH/STH and EST/WST
                                    10) WX Sat Turnstile
                                    11) The antenna hanging down from the longwire (second from the right) is an experimental helically wound HF vertical contained in a 2 meter length of conduit (left over from the coxial collinear build) i made last weekend. The premise was to make a portable antenna with a decent electrical length that would not get tangled or bent/broken for when i go camping. I installed a hook in the top so it could easily be mounted. In this case, hanging from a wire. The results are on a par with the longwire which is better than i expected so far, but more about that in a later post.

Monday 15 July 2013

Following ships via GMDSS

         Here's a short demonstration of how i can follow ships using their HF GMDSS signls. I initially use 3 programs (linked via com port) and in this case we are following the MOL KOMATI:

1) HDSDR to receive the signal via my Soft66LC4:
HDSR showing the GMDSS signal (1st on the left)
2) Patrick Lindeckers MultiPSK to decode the signal and send it to:
3) Mike Simpsons GMDSS Display program:

GMDSS showing vessels and details

           I would say that 99% of vessels out there do not send their position details due to many reasons, security being the main one. However, GMDSS Display has a function whereby pressing the ships code opens a Marine webpage showing not only the vessels details and pictures but also its current position and track:

Marine MOL KOMATI details

MOL KOMATI's position and track

Wednesday 10 July 2013

My 3 Point approach to tracking local aircraft

                    I thought i would quickly show how i'm able to track aircraft in southern airspace. I now have Plane Plotter and ADSBscope set up properly so i'm able to get information from both ACARS and ADSB and plot them on maps.
                    Firstly and most basically i can hear air traffic conversations:
voice transmission on SDR#
                    Second, Plane Plotter takes data from ACARS transmissions, logs and plots them on local maps (which are a pain in backside to implement). However, because aircraft are moving so fast, it isn't always possible to receive locations consistently.
message content
location data showing some locations missing
plotted onto local map
                    Third (to cover data gap in ACARS) i use ADSBscope which is VERY dependable in the amount, range and frequency of data sent.
ADSBscope showing data missing from ACARS
                    So when i sit down in front of the pc and laptop, it's a great feeling to know i have all the bases covered. I never thought "plane spotting" would be of any interest to me, but with the right tools, i always have something to do when HF conditions aren't great.


Wednesday 3 July 2013

Project 10: A quick extention to my desk

             I recently got a laptop so i have a dedicated pc for all my radio software. The problem was that i had no room left on my desk. The solution? $20 spent at the reject shop got me a bookshelf that would be ideal. All i really needed to do was cut it down to size, fit a bracket so my dog won't move it in her quest to lean on everything i own. Mrs Phil even chipped in and surprised me with some black and silver containers for the shelves.
almost looks like it was part of the desk

everything at my finger tips

Tuesday 25 June 2013

Mountain Radio Challenge

Mountain Radio Challenge, or MRC, is an annual CB Radio event held on the last Saturday in November each year. It is when a group on enthusiasts head out to different mountain tops to set up for the day, or weekend, and try to pass a series of messages along the line via ground wave signals between stations up to 150km's apart. Last year there were 10 stations, and I was set up on Mt Arapiles in Western Victoria as station MRC 4.

I used a Uniden Grant LT 40 channel am/ssb, with a 1/2 wave vertical antenna mounted on a telescopic mast with a short run of RG58 coax. Power was by two 12v batteries, one for the radio and one for the small inverter to run my laptop. Portable solar panels helped keep the batteries topped up.

It is a lot of fun, and a good excuse to set up in the field. Plenty of skip contacts also before the official start time of 2pm, although contacting MRC stations either side is a must before hand to ensure there are no  surprises, resulting in the message not getting through once the event starts. Any one interested can go the the web site and contact Tony to get involved. Had stations across several states in the past.
Mick 361

Thursday 20 June 2013

Plane Plotter...My new toy.

                    HF condx have been absolutely appalling recently, so i've kept myself busy in the VHF/UHF parts of the spectrum, particularly ACARS and ADSB. I have been testing 3 ACARS specific decoders to use with my RTL-SDR (i have several programs that do it, but not to the fullest degree).
                    These programs were: ACARSD, KG-ACARS and Plane Plotter. ACARSD is a nice looking bit of software that presents images of the aircraft that are decoded as well as plotting these on a map, which the user must supply and calibrate (a frustrating experience if ever there was one!!). But i persisted and was rewarded with quite a good program....when it decoded. This is the only issue i had with tended not to be as sensitive when compared against my benchmark software (MultiPSK, Sorcerer and PDW) and it was missing aircraft with very good signals. The user interface and setup are highly configurable and the price is right at zero,nada,zitch.
                    KG-ACARS is also free. However i had 2 main issues. 1) The GUI is in Japanese and fairly minimalist. There is an English instruction document within the download that is fairly good but also is a little ambiguous. I found this to be trickier to set up than the ACARSD map! 2) As the software is intended for use in Japan, we are warned that it may not decode ACARS TX from other international aircraft. A real shame in my books, because i thought this was a very nice program.
                    So we come to COAA's Plane Plotter. I had the free trial of this for a while until i had something to compare it to. I have to say that i LOVE this comprehensive, easy to set up and use, detailed, never skip a beat decoder! AT 25 Euros ($35 AUD) this delivers a lot of bang for your bucks. You don't get the pretty images of aircraft, oh no....this is a decoder for those who like straight forward data and modes. You get all of what the other 3 offer plus much more (but you still have to build and calibrate your own maps of course, after's character building right?). It handles ADS-B, SBS, BEAST, RTL1090 (plus more) and even downloads satellite images for your area and plots them (satellites) at night. I purchased it 2 days ago and haven't stopped using it yet. I have run it alongside my benchmarks as well as watching flightradar24 to see if it was missing any contacts...nope. Money well spent.
                     In summary, there are many aviation programs out there ranging from free to VERY expensive. With the free ones, you get what you pay for and with the expensive ones....well, they're expensive! Plane Plotter sits nicely in between and is by no means average.
                     Here are just a few of the many available details:

Plotting on my (Googles) calibrated map


aircraft view


Wednesday 12 June 2013

Project 9: A coax collinear antenna for ADSB

           Another VERY quick antenna project to enable better reception for my ADSB system. I used the method described here: by Dusan Balara (thank you!).
           The antenna is simply 8,12 or 16 (i went for 16) 116mm (plus 50mm) sections of coax, with each end of each section stripped allowing 25mm of solid core which is then inserted between the outer jacket and braid of the next, giving it an offset appearance. A small piece of plastic is placed between each of the core sections to avoid shorting. The joins can be taped if you're in a hurry, but i love using heat shrink and it restricts movement better.
16x116mm sections
plastic squares for insulating the cores
keeping the cores insulated
a small section of the completed 2metre long collinear. note the off center appearance.
The finished product (center) , added to my growing farm.
           A 2 metre section of sparkies conduit from bunnings is used to house and protect the collinear, seal the top (i found an old cap from a roll of copper that a plumber left behind), seal the base and up she went.
           This was the fastest of my builds to date (taking just over 45 minutes) and the cheapest. 2 metres of 75ohm RG6 cost $2, 4 metres of conduit ( i will use the other 2 metres on my next project) cost $4. I don't know how much this antenna would cost to buy, but i'm certain it won't be $6!!
           Apparently this antenna is said to have excellent "horizon" qualities, and this is indeed the case. In testing this evening, i am receiving aircraft far earlier and losing them far later than last nights session with the discone.

Sunday 9 June 2013

Using the RTL 2382U as an Automatic dependent surveillance-broadcast (ADS-B) receiver

          Ive been making good use of my RTL to receive ACARS with ACARSD recently and was looking for something a little more technical. Some googling led me to ADSB# which in turn led me to ADSBScope. Well, i spent 6 frustrating and ultimately fruitless hours of my life trying to get ADSB# to work, no matter what i did, even down to uninstalling the drivers, it just would not work. Then i found RTL1090. What a joy this piece of software is to install and use! RTL1090 is the necessary link between the dongle and ADSBScope, tuning to 1090MHz and providing the data for ADSBScope to plot.
         Both programs are well documented on the net and simple to install. At first i was dubious as to whether the dongle would actually work in the GHz range. Anecdotal evidence says it will, but each dongle seems to have its own intricacies. Fortunately,  the RELWITHDEB zip i downloaded contained a test file that indeed showed it could. (how much more can this great little stick achieve?? actually, i have read that it is possible to modify it to receive below 30MHz!!...but thats for another day).
         The following shots are taken just after i got it running and i have spent a very enjoyable day watching my "RADAR".
RTL 1090


2 aircraft plotting

Wednesday 5 June 2013

Playing around with SailMail PACTOR 3

Recently there has been some discussion in my UDXF group about the difficulties of decoding SailMail PACTOR 3, so i though i'd give it a shot. Surprisingly, i had no problems . This was decoded on 10474.7kHz using Sorcerer:
PACTOR 3 signal

PACTOR 2 preamble (i assume)

And the decoded PACTOR 3 data

Friday 24 May 2013

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#                      


Friday 17 May 2013

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.
Mick 361.