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