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Wednesday, 30 August 2017

Causes of poor radio reception

(This was posted to the SA-Scan group and is reproduced with permission)

As the 2 way radio scene is rapidly changing from analog to one of the many digital transmission
formats available and the SA GRN network will be switching to a full digital system in the near future there is going
to be new challenges in receiving good quality digital transmissions and opinions will always differ, there is sometimes no one singular fix to receive a good quality digital transmission if you are receiving corrupt transmissions in some cases.
This is a guide to possible causes to poor 2 way radio digital transmission reception and is open to many different
opinions, agreements or disagreements and may help fix reception issues you might get with digital transmissions.

The scanner or radio receiver.
The scanner is often the biggest weakness as the majority are not true narrow band receivers by 2 way radio standards.
In Australia the standard bandwidth for VHF & UHF band 2 way radio is 12.5 kHz channel bandwidth with 25 kHz still
allowed in remote locations, most digital transmissions are 10.8 kHz bandwidth with a little spare on the side.

Most scanners have a 30 kHz channel bandwidth which allows for adjacent channel bleed through, this is the most common cause for interference and affecting how well digital transmissions are decoded, now in analog we would hear that interference but as long as we can hear what is being said we tend to ignore the interfering noise, digital on the other hand if that interference is strong or noisy enough it will cause the received digital transmission
to start chopping in and out (breaking up) or not to decode it at all, there is no real fix to overcome this and the problem
is more prevalent when monitoring multi site trunking networks where there is a lot of adjacent channel transmissions,
This is also more common in large metro area's where there is a large amount of 2 way radio traffic and less problematic
in rural but can't be ruled out.

Electrical interference.
Household.
This can be caused by many different sources, from poor quality LED lighting to cheap E bay electronic goods
but even quality manufacturers can even have the odd problem product, rooftop solar systems where the manufacturer has used poor quality electronic components that give up in the grid interactive inverter and allow noise in the electrical system.
Earthing faults within the household though rare can happen and earth loop back noise will cause problems.
Most often these can be identified by a buzzing noise when listening to analog transmissions.
Sometimes the interference could be coming from a neighbours house or 2/3 away.

Motor vehicle.
Even in today's modern vehicle electrical interference still happens from alternator, ignition and electronic PWM
ventilation fan speed operation, some vehicles radiator fans are even PWM variable speed control,
poorly manufactured electronic circuits on after market HID and LED lighting is the biggest culprit.
Some alternator voltage regulators can cause noise when under heavy electrical loading.
Also earthing faults within the vehicle is another common fault.
It could also be coming from a vehicle near you while travelling.

The receiving antenna.
In the household environment the most popular type is the discone due to it's wide bandwidth of frequencies it can cover.
It has it's pro's and con's but depending on your location it can either reduce or contribute to RF interference,
this is a tricky one where there will be difference of opinions.
A dedicated frequency band antenna again has both pro's and con's like the discone but limited to the frequency band it's designed for and will perform very poorly outside of that band.
The old height is might saying, it is generally true but again if you are in a heavy RF area it can actually increase interference as the antenna becomes more exposed to RF signals from more sources.
The gain antenna, again more difference of opinions here, it can help but it can be a cause to more interference being received.
On the vehicle either an average frequency trap wide frequency band scanner antenna or a dedicated frequency band antenna not much give here but in heavy RF environments the scanner will suffer no matter what.

Handheld scanners often are provided with either a basic antenna tuned for a centre frequency that the scanner will cover from lowest to highest frequency and not work to well outside of the centre frequency, some might come with a
compromised band trap type, if you are using the scanner at an event where the frequencies you are monitoring are
centralised a frequency dependant band type antenna might be a better option.

Coax cable on a base set up.
Using the wrong cable can possibly lead to interference, also using RG58 over a long run will also cause heavy attenuation of the incoming signal thus creating a cause for poor signal strength and quality at the receiver, also use quality connectors and limit as much as possible the amount of connectors or adaptors used, this always lead to data quality issues as each connection point adds attenuation and in rare cases can be a cause for an interference point to happen.

Do you need to have a look at your existing set up, yes you may have to, what might have been OK for analog might
be an issue to receive good quality digital transmissions, this is to help there is some cases due to your location
you may have interference that you will not be able to eliminate.

There are members on this group who have vast experience in the RF field and no doubt would be willing to help,
never be afraid to ask we all started out green and inexperienced at one stage but there will be difference of opinions on some of the above.

There is most likely other points I haven't covered here but it is a starting point.
Happy Scanning.

Tuesday, 29 August 2017

Dick Smith Electronics Catalogue 1992

A few pages from back when Dick Smith Electronics was both still open and actually stocked radio related items. Some good memories here.




Monday, 28 August 2017

Ben Lomond Photos

Recently we went for a day trip to Ben Lomond. Below are some photos and the details of the radio communications sites on this mountain. Ben Lomond is the second highest mountain in Tasmania.

88 MHz Seventh-day Adventist Church (Australian Union Conf.)
433.05 MHz Northern Tasmanian Amateur Radio Club Inc
438.05 MHz Northern Tasmanian Amateur Radio Club Inc
474.125 MHz Warren J Speers
476.475 MHz North East UHF Repeater Association
477.225 MHz North East UHF Repeater Association
479.325 MHz Warren J Speers
853.9125 MHz Bureau of Meteorology
929.9125 MHz Bureau of Meteorology









Sunday, 20 August 2017

News on VK7RAA Interference from the WIA News

This is something I have heard myself, to the point that I have had to "avoid" this frequency due to to it locking up my scanner.

“We have recently been experiencing intermittent interference on the VK7RAA 2m repeater. It seems to be originating from aircraft transmissions possibly in the Devonport area or adjacent to Mt Arthur. As the originating signal is AM, when received on an FM receiver it sounds distorted.

From investigations carried out so far, it seems to be from one particular aircraft. Flights involved occur about 3 times a day to Launceston and Devonport, however, it is not always the same aircraft being used. Aircraft also may have two or three transceivers which makes the job of identifying the source even more complicated.


This interference is being investigated by several amateurs in the Launceston area.


In the meantime, please do not attempt to reply on the repeater to distorted calls which do not seem to be by amateur operators."

Tuesday, 15 August 2017

Radio Go Case - August 2017

Over the years, while involved in the radio scanning / amateur radio / ultralight DXing hobbies, I have used a number of different bags and cases for carrying my radios and associated bits and pieces. Some of these bags and cases have worked very well, others have not for various reasons.

I have again returned to my love of portable operation, this has meant finding a suitable carry case or bag for my radios to undertaken these activities in parks and other locations.
Based on my experience in the past, I decided to move away from a soft bag like I have used recently and started looking around for a hard case. This needed to be big enough to hold my Uniden UBCD436PT, aerials, chargers, USB cable and ear phones. The "lunch box" case I have been used has served me well but I wanted something stronger and with better protection.

Jaycar sell a number of ABS cases, based on the size I needed I decided on this model "ABS Instrument Case with Purge Valve MPV1". I was lucky enough to get this on special for $31.95, saving $8 off the RRP. The foam that comes with them is not great so I removed this and instead installed a divider which is wrapped in bubble warp, providing a good level of protection to my UBCD436PT. I also installed some bubble wrap in the base and used double sided tape to secure the top lid foam.

The below photos show my final setup, this works well, provides great protection to my UBCD436PT and is still small enough to travel with me in my back pack.






Saturday, 12 August 2017

UBCD436PT Key Press Codes

2 + 9 + CHAN MOD = MEMORY CLEAR
CHAN MOD + 1 = LCD / Keypress test
CHAN MOD + 2 = LCD Contrast Adjustment
CHAN MOD + 4 = Tone Out Test
CHAN MOD + 9 = Clock Reset
SYSTEM + 1 = Close Call Test (Knob controls band)
SYSTEM + 2 = USB Serial Test
SYSTEM + 4 = Load Test Data 144MHz
SYSTEM + 5 = LCD Brightness
SYSTEM + 6 = Load Test Data 163MHz
SYSTEM + 7 = Trunking Test
SYSTEM + 8 = NWR-SAME Test
SYSTEM + 9 = Load Scan Test Data


Wednesday, 2 August 2017

Upper Burnie Lookout



Braddons Lookout

Today I was down the North West for work. On the way I stopped at Braddons Lookout to see how many EDACS control channels I could hear. Below is the list, this would have to be close to the most you could hear from any location.

865.1125 = Transend Site COMPANION HILL TAS 7321
865.1625 = Wynyard Transport Site TABLE CAPE TAS 7325
865.1875 = Ericsson Site GARDNERS RIDGE TAS 7304
865.2125 = Radio Terminal KELLYS LOOKOUT TAS 7303
865.2375 = Hydro Electric Commission Site KELCEY TIER TAS 7310
865.2875 = Air Services Australia Tower MT BARROW TAS 7259
865.4625 = Vodafone Site Off White Hills Road SULLOCKS HILL TAS 7316
865.4875 = Telstra/Ericsson Site MONTUMANA TAS 7321
865.5125 = Council Community Site ROUND HILL TAS 7320
865.7625 = HECT Site MT CLAUDE TAS 7306
865.8375 = Weather Radar Site WEST TAKONE TAS 7325









Tuesday, 1 August 2017

Tasmanian 000 Services Frequency Guide


Tasmanian 000 Services Frequency Guide

Updated: September 2016





Tasmania Fire Service

The Tasmania Fire Service is unique in Australia, in that the 'rural' and 'urban' brigades are the one entity, the Tasmanian Fire Service. As such there is no division between those brigades in the metropolitan and country areas. All brigades use the same VHF radio system.  Volunteer personnel form the bulk of fire fighting brigades in the country, and volunteers support the regular fire fighters in the metropolitan areas.  The only 'retained' fire fighter stations are Hobart, Launceston, Devonport and Burnie.



In the past the TFS channels have sometimes used for special events, such as Targa Tasmania, although this does not seem to happen anymore. As more people have and use UHF CB’s, the TFS has developed a policy in which at a fire UHF CB channel 12 will be used as a fire ground chat channel between TFS vehicles also for landholders to get help and communicate, UHF CB channel 13 may be used for specific communications in emergency's also, where the TFS radios on VHF may not be helpful, e.g. a landholder stuck and wanting specific advice or similar.



Frequency       Channel Numbers      Area covered or use

76.0375           F35                              Major Incident 5 - simplex

76.4875           F34                              Major Incident 4 - simplex

77.0000           F33                              Major Incident 3 – simplex

77.5875           F37                              Major Incident Repeater2

77.7500           F36                              Major Incident Repeater1

78.0375           F38                              Portable Repeater

78.0625           F9 & F30                     Devonport & Hobart secondary

78.3375           Nil allocated                Tasman Peninsula area

78.5250           F11 & F24                   Northern Midlands & far North East region               

78.5625           F5, F18 & F25             Mersey Valley, Flinders Island & Southern Midlands

78.6500           F16 & F23                   Tamar Valley / North-east & South-East Region

78.6875           Nil allocated                Mole Creek / Deloraine area

78.8875           F1 & F20                     North West region & South-East region & training

79.0375           F8, F19 & F29             Burnie, Launceston & Hobart (Main urban frequency)

79.1375           T3                                Dover area

79.5000           Nil allocated                Bothwell area

79.5625           F2, F10 & F28             King Island, Northern region & South-East region

79.6000           F6, F14 & F26             West Coast, Esk Valley, Midlands & South-East region

79.6125           F7, F15 & F27             West Coast, Esk Valley / East coast & far Southern

79.6500           F4, F13 & F21             Far North-West region, Far North-East & Southern East

79.6625           F3, F12 & F22             North West, North East, East Coast and Flinders Island

79.8375           F32                              Major Incident 2 - simplex

79.9375           F31                              Major Incident 1 – simplex



(All the above channels are repeaterised (except where noted as simplex), but operators can select low power simplex for car to car operations, base will not hear these simplex operations)



The TFS also has other channels programmed into their radios that operate on the Forestry and other timber producing companies and State Emergency Service frequencies. 

In particular instances Ambulance, heavy industry, councils and a few miscellaneous channels are programmed in to some radios should the need arise to liaise with other services.



Other frequencies:

The TFS have in recent years installed “on truck” repeaters in the 400MHz UHF band, these are used to allow crews to talk to each other and back to the truck which then links in to the main VHF channels as above. These frequencies are well worth having programmed in.



411.18750       TFS UHF SIMPLEX

411.61250       TFS UHF SIMPLEX

412.36250       TFS UHF SIMPLEX

415.46250       TFS UHF SIMPLEX

415.47500       TFS UHF SIMPLEX

415.48750       TFS UHF SIMPLEX

415.51250       TFS UHF SIMPLEX

415.53750       TFS UHF SIMPLEX





Call signs:

The base is always referred to as 'FireComm', and has its radio room centralised in Hobart.

Units are initially referred to by their originating station name, and a two digit number which indicates their type:



1-1.0                Sedans / station wagons

1.1-2.0             Urban heavy pumper, 4 person cabin. (In main city stations)

2.1-3.0             Urban medium pumper, 4 person cabin

3.1-4.0             4WD heavy tanker, (some new 3.xP are now active with a 4 person cabin)

4.1-5.0             4WD medium tanker

5.1-6.0             4WD light tanker

6.1-7.0             Metropolitan appliances - Simon Snorkel & Teleboom

7.1-8.0             4WD dual cab utility

8.1-9.0             Rescue, HazMat & miscellaneous

9.1-9.9             SES Rescue vehicles



Division Vehicles:

Vehicles attached to commission divisions, that fit the above descriptions will also be numbered according to this system. Vehicles at the training division then become “training 2-1” and “training 2-2”



Personnel:

Commission officers, and senior brigade personnel, both career and volunteer, are referred to as their own personal call sign this is because they sometimes shift between vehicles at large vegetation fires, or may be using a portable radio. Examples of these are below:



Position                                                                      Call sign example

Chief Officer                                                               Commission 1

State manager, Engineering Services                       Engineering Services 1

State manager, Communications Division                 Communications 1

Regional Officer (e.g. South)                                      Southern 1

Group Officer (e.g. Derwent)                                      Derwent 1

Brigade Chief (e.g. Hobart)                                        Hobart 1

Second Officer (e.g. Kingston)                                   Kingston 2

District Officer, (e.g. Hobart Operations)                    Hobart 2

District Officer, (e.g. East Coast)                                East Coast 1



Base station                                                              Call sign example

State-wide Dispatch Office                                        Firecom

Regional Control Room (e.g. North)                          Northern Base

Group Headquarters (e.g. Derwent)                          Derwent Group

Brigade Station, (e.g. Glenorchy)                              Glenorchy Station



Aircraft:

Air Services Australia have allocated standard call signs for use by aircraft operated by authorities, for fire fighting purposes. The first prefix “7” identifies the Tasmanian based aircraft. The second allocates the type, and the third is the typical “issue number”



Aircraft                                                                       Call sign example

General fire support aircraft                                       Firebird 701, 702 etc.

General fire support aircraft (crew insertion)              Helitack 711, 712 etc.

Fire bombing aircraft (Fixed and rotary)                     Bomber 721, 722 etc.

Co-ordination of fire bombing aircraft                        Birddog 741, 742 etc.

Intelligence (Fire) gathering aircraft                           Fire spotter 751, 752 etc.

Remote sensing fire operations aircraft                     Fire scan 761, 762 etc.



Pro-Words

The Tasmania Fire Service uses a formal style of communicating, but it is good to note that all pro-words used by the fire service are not “implied” as such, and are understandable to the layman. The only pro-words worth knowing are the vehicle movements. These are:



Pro Word                                           Meaning

Mobile/Responding                             en route to an incident

Arrived - Establishing * control           First vehicle on scene ( * = nearest landmark or street)

Arrived                                                Second, third etc. appliance arrived on scene

Closing Down                                     Closing down the incident control

In service                                            Vehicle in service, able to respond to other incidents

Returning                                            Returning to their respective station

Stationed                                             In service, and stationed at their respective station



Other call signs:

F.I - followed by a number: Fire Investigations

CommTech - Communications technicians

Portable followed by a number - Handheld radio which originates from an appliance of the same number i.e. Launceston 1.1 & portable 1.1 are the same crew.

Code orange/3 - Normal road conditions

Code red/1 - Lights and sirens.



Upon arrival to the fire scene, the senior officer will assume the call sign of the street name or locality appended with ‘control’; for example "Brisbane Street control" or "Kmart  control" or “Queechy high school control”

All messages are passed without codes in plain English, and are quite descriptive which makes listening to the fire service easy.





Tasmanian Ambulance Service

The Tasmanian Ambulance Service (TAS) is the government run ambulance service covering all of Tasmania. The frequencies below are 'repeaterised', except where noted. In areas where the network does not reach, such as the west coast and far north east and far north west, the ambulance will share the local fire service frequencies, only using different CTCSS tones.



77.1250                                   Car to car simplex state wide. (Not logged in a few years)



Southern Tasmania

77.2375                                   Hobart city simplex                

78.2500                                   Mt Wedge

78.4125                                   Mt Rumney (Hobart area)

78.9125                                   Mt Faulkner (Hobart & southern Tasmania)

78.9250                                   Herringback (Huonville & surrounding areas)

78.8625                                   Mt Koonya (Tasman Peninsula area)

78.8500                                   Bradys Sugarloaf (southern central plateau)

79.0875                                   Mt Hobbs (southern Tasmania)



Northern Tasmania

78.7750                                   Millers Bluff (Northern Midlands)

78.6250                                   Mt Barrow (Launceston & North East Tasmania)

78.7000                                   Mt Dismal (Tamar valley & Launceston)

79.0625                                   West Launceston (shared with Fire Service)

78.8250                                   Dazzler Range (central north Tasmania)

78.4875                                   Flinders Island



North West Tasmania

78.3750                                   Kelcy Tier (Devonport)

78.2500                                   Sullocks Hill (Penguin / Ulverstone)

78.5125                                   Montumana (Rocky Cape area)

78.9125                                   Companion Hill (Hampshire area)

79.3125                                   Round Hill (Burnie)

79.3500                                   Mt Claude (Kentish area)



Other frequencies:

The Tasmanian Ambulance Service have in recent years installed “on truck” repeaters in the 400MHz UHF band, these are used to allow crews to talk to each other and back to the truck which then links in to the main VHF channels as above.



410.98750       AMBULANCE UHF SIMPLEX

411.31250       AMBULANCE UHF SIMPLEX

411.76250       AMBULANCE UHF SIMPLEX

413.70000       AMBULANCE UHF SIMPLEX



The ambulance service also has access to the fire service, council and miscellaneous other channels.



Call signs:

The base is always referred to as 'T.A.S.' and has its radio room centralised in Hobart.

Vehicles are identified by a three digit number, with the first digit indicating the type of vehicle:

100-399           - Administration vehicles

400-499           - Patient transport vans

500-599           - Supervisors station wagons, carrying medical supplies, but unable to do transports

600-699           - Rescue units

700-799           - 'Regular' ambulances

800-899           - 'Light' ambulances

900-999           - 4WD ambulances

MedEvac 1      - Air Ambulance



Codes used:

A & E - (Sounds like A.N.E) Accident and Emergency at the Hospital.

D.E.M - Department Of Emergency Medicine. (Is replacing A&E above)

QV - Queen Victoria Maternity Unit - Used for the arrival of newborns.

TNR -Transport Not Required.

A / Alpha - Serious condition; life threatening. (Old CAT 1)

B / Bravo - Serious condition; not life threatening. (Old CAT 2)

C / Charlie - Patient dying unlikely to live.

D / Delta - Not urgent or low Priority. (Old CAT 3)

E / Echo - Patient deceased. (Old CAT 5)

Alert 41 – Police required

DOA – Dead On Arrival

PFO – Patient Fell Over.



The TAS radio system is probably the least interesting to listen to, since much of the communication about jobs is done before the ambulance leaves the station, and selcalls are used to indicate the status of the ambulance: proceeding to job; arriving at job; leaving job for hospital; and lastly clear of hospital & clear to take new jobs.  There are other codes, but the above codes give you the general idea.                



St John Ambulance

Existing VHF allocation:

76.9125           St John ambulance allocation simplex



This new network is presently being installed across the state; however it is not yet operational.  It appears to be designed to support the SJAs operations at major public events (shows, sporting events etc.) The frequencies below are for reference only.



469.525

470.000

470.150

470.400

470.975

472.150

472.200





State Emergency Service (SES)

The SES is a volunteer based, Emergency Response agency, supported by a small number of permanent staff members located statewide. The SES utilizes the following channels in their Road Accident Rescue, Search and Rescue, Storm Damage and General Response roles.

Frequency,
     Channel          Area / use
78.7125
           81-83               Grass Tree Hill, Snow Hill and Tyler’s Hill Repeater

77.675             84                    Mt Maria & Bonneys Tier Repeater
79.7500
          85                    Mt Koonya Repeater
78.9375
          86                    Bradys Sugarloaf Repeater  (Planned Repeater)
77.5250
           87,90,91          Mt Arthur, Table Cape and Mt Cleveland Repeater

79.2250           88                   South Sister Repeater (Planned Repeater)
78.1375      
     89                   Mt Horror (Planned Repeater)
78.7125      
    92                   Mount Read (Planned Repeater)
77.5250      
     94                   Simplex Operations
79.0250      
     96                   Police SAR Repeater (Planned Portable Repeater)
78.4500      
     98                   SES Portable Repeater
76.400      
       99                   Disaster Liaison Channel (Simplex Operations)


The SES uses the standard VHF Tasmanian Emergency Services Radio Plan, Which gives access to TAS Fire, TAS Ambulance, Forestry Tasmania, Parks and Wildlife, Council and Private Forestry Company radio channels.

SES can be heard on TFS channels when attending Road Accident Rescue incidents (ie. "Unit Name 9.1" 9.2 9.3 etc" call signs) on Channel 98 or 99 during Search and Rescue Operations and on their local repeater or simplex channel during Storm Damage incidents and other SES activities. Some SES staff members also have access to the Police EDACS system (Police Call Groups, Romeo Call signs) for inter-agency communications if required.



But what about the Tasmania Police Service?

I have purposely omitted the Tasmania Police Service channels for a few very good reasons.  The TAS Police use a sophisticated 800 MHz EDACS trunking radio network. At the best of times is very difficult to listen to and you will find that a considerable percentage of their communications uses "Provoice" digital encrypted transmissions.

The only active VHF frequency is:

79.0250 - Police Search & Rescue portable repeater



The Tasmania Police Service also have two VHF air band frequencies which get very little use however, they may be handy to have, just in case:

119.1000         For helicopter use

131.6000         For helicopter use



A final note:

Please don't use this information to go 'chasing ambulances'.  The professionals of all emergency services have a job to do, and wouldn't appreciate you getting in the way with your scanner.  Use your scanner sensibly, and stay well out of the way.