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Home 4WD HF Radio FAQs |
Frequently Asked Questions
Frequently Asked Questions. |
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There are 10 entries in the FAQ. Pages: 1 Questions:
How far will my HF radio transmit??
Which radio should I buy, Codan or Barrett??--What Model would suit me??
What is a "Local" and what is a "Remote" head radio?
What style of antenna should I use?
What is Selcall and Telcall?
Which radio network should I join?
My HF radio is not "getting out" in my 4WD Vehicle-What could be the problem?-How can I test my antenna??
I cant seem to receive anything, All I can hear is "Hash & Noise".
Can you modify my radio to do.....??
Can you supply programming software to suit my radio?
| How far will my HF radio transmit?? |  | The short answer is from 20-20000km - I will offer an answer that relates to Aussie 4WD Networks-It is not an exact science though .
You may notice that most of the 4WD networks use a channel close to 8000Khz (8 Mhz) as their main frequency and 5000Khz (5MHz) as their secondary frequency. There is a reason for this --- 8 Mhz is a "good all round" channel during daylight hours, it will work up to about 30 km via groundwave and from 400-1000km via skywave. As for 5Mhz, this tends to be used for shorter skywave distances (say 300-700 Km)-normally in the early morning or early evening. Note that you will normally have a " black hole" in the transmission range between 30km-200km. This hole is where the groundwave cant reach, and the skywave bounces straight over the top of you. Most networks also have a 14Mhz channel--Nomally pretty useless at night, will usually work well from 1500-3000Km skywave during the middle of the day.
This is as a guide only-There are a lot of variables when it comes to HF communications...I recommend that you do some of your own homework to fully understand HF radio systems. Comments:
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| Which radio should I buy, Codan or Barrett??--What Model would suit me?? |  | Barrett and Codan are both well built Aussie radios--It really is personal preference-You will however pay about 15% more for an equivalent Codan radio, purely because the Codan name is a little more popular.-All dates below are an approximate guide only.
Barrett Model Timeline:
~BC 220/225 1980-1990 -12 channel crystal locked radio. ~BC 250 1987-1993 - 250 channel with optional selcall-Optional telcall available on radios fitted with Ver. 4 or 5 firmware.
~BC 550 1993-1997 - 500 channel with selcall/telcall etc.
~BC 950 1997-2003 - Upgrade of the 550 with a few extra functions.
~2050 2003-Current - Easy to use radio with pretty much all the bells and whistles.
Codan Model Timeline:
~6924/8121 "Lunchbox" Radio 1975-1985. - These popular 50 watt radios had a built in tuner, so basically all you needed was a piece of wire to throw over a tree as an antenna / then "Tune Up" and you're ready to go. The early model had a few reliability problems, but the 6924 MKII and 8121(Marine version) were quite good. ~7727/6801/7515 and variants 1975-1985 - Normally a 10 channel/100W Crystal locked radio-The 7515 was a 6 channel/50W radio.
~8525A/B 1985-1992 - 99 channel eprom programmable radio with optional selcall. ~8727 1985-1992 - 10 Channel Crystal locked radio with similar cosmetic styling to the 8525-No Selcall option.
~8528 1989-1995 - 400 channel with selcall/telcall--These radios are still sought after.-Amateur and TXE options available. ~X2 1990-2000 - Extremely well built "PC Programmable" 10 channel radio-No selcall option. ~9313/9480 1989-1994 - Basically a 15 channel version of the 8528 - Selcall only. The 9480 had the LSB option.-Generally these radios can be easily upgraded to a 8528 if you have access to a 8528 keypad & eprom. ~9323/9360 1993-2003 - 400 channel with selcall/telcall etc. Widely considered in radio circles as the best 4WD HF radio ever built--Still very popular. ~9780 15 channel version of the 9323/9360. ~NGT 2001-Current - Pretty much all the bells and whistles--Uses a "Mobile Phone" style of mic / handset. Comments:
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What is a "Local" and what is a "Remote" head radio?
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A "Local" radio is an "all in one" unit, whereby the front control panel and main radio transmitter box are one complete unit. This style of radio is quite popular for marine and home base use, but can sometimes be a little impractical for mobile 4WD use. A "Remote head" radio has a relatively small control head, which attaches to the main transmitter box via an interface cable. This allows you to tuck the larg-ish main transmitter box under the seat etc, and mount the head on the dashboard/console etc.
Pretty much all Barrett and Codan models can be bought in either configuration.
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| What style of antenna should I use? |  | There are two main styles of mobile antennas available- Autotune and Multitap.
An Autotune basically does what the name implies--It automatically tunes itself to suit the frequency selected on the radio.
Advantage: -Makes life easy when swapping frequencies. Disadvantage: -High Cost / Generally has to be reconditioned every 5 yrs or so.
A Multitap has to have the "wander lead" moved each time you change frequency.
Advantage: Low cost / Reliable-No servicing required Disadvantage: Limits the amount of frequencies available on the radio / Have to manually change aerial tap.
Popular Models of autotunes:
Codan 8558--Requires an interface box or circuit board to operate---These antennas are pretty much at the end of their useful life---Not recommended.
Codan 9350 -Very popular--Will plug straight into 8525A/B, 8528, 9323, X2, NGT--Note that the NGT uses a different antenna interface cable.--There are a few versions of these antennas (A to F prefix), dont worry too much about the prefix, as long as it has been serviced over the last few years it will of had most of the upgrades anyway.
Codan 3040 -New-- This antenna uses an electronic tuner rather than a stepper motor to drive the antenna--I believe that the electrical connections are identical to the 9350, so it will happily work with the 85xx, 93xx & NGT series of radios. Note that although the stud on top of the autotuner has a 14mm thread, the spring supplied with the 3040 steps down to 12mm for the actual whip mount. Barrett 510/910 -Very popular---Just ensure that you get one with the mid to dark grey casing. The very early model 510 (off-white colour) has a tendancy for the outer casing to crack.
Barrett 2019 -New- This very robust antenna, is quite sleek looking.---It can also be supplied with an internal GPS antenna/receiver. Note that the 2019 uses a different control lead to the 510/910. Comments:
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| What is Selcall and Telcall? |  | Selcall is a 4 digit calling system between radios:
When you sign up with a network, you will be given a 4 digit selcall number (nomally the same 4 digit number as your callsign). Basically its a signalling system, whereby you can call a base station or another network member. When the receiving station "gets a hit" on its selcall number, it transmits a short "Revertive Tone" across the channel, so that station sending the selcall knows that the receiving station has received the selcall. The radio that receives the selcall also starts "ringing" inside the car, and displays the selcall number of calling station. The selcall system is widely used on all radio networks. Nowdays it is pretty much essential that you buy a radio with this option if it is to be used as a Land Mobile system (ie. fitted to your 4WD) .
Telcall is the ability to make outgoing phone calls from your HF Radio.
If your network supports telcall, you will be asked if you wish to use telephone interconnect when you sign up. . This will allow you to make direct dial telephone calls via your HF radio to any Australian landline or mobile, 24 hrs a day. Call charges vary between HF Networks. Some networks offer a prepaid pay as you go system, and some have a fixed annual fee for unlimited calls. Note that Telcalls are generally restricted to about 6 minutes.
Networks that currently support telcall are: HF radio Network. Radtel. Reids Radio Data. VKS737.
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| Which radio network should I join? |  | Popular Network operators within Australia:
Austravel (VMD750) HF Radio Network (VKE237).
Radtel / HF Oz
Reids radio Data / Bush Telegraph (VMS469).
RFDS Network.
VKS737 HF Radio Network / HF-Tel.
Annual licence fees vary, but range from about $40-115. No licencing test required on a 4WD network , just pay your money and away you go.
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| My HF radio is not "getting out" in my 4WD Vehicle-What could be the problem?-How can I test my antenna?? |  | Firstly-Dont panic. In my experience, only about 1% of problems are actually bona-fide faults within the radio or antenna system. If I were to break it down, I would say that: 60% would be bad earthing of the antenna-Always earth the antenna base mounting bolt directly to the body of the car.-Dont just rely of the bullbar mounting bolts as your aerial system earth. 30% would be a faulty coax lead.-Always test for short circuits after fitting the coax connectors. 15% would be a bad power feed-Always use 4-6 mm2 cable, and a physically large 25-30 Amp fuse or circuit breaker.-Do not use a small glass(3AG) or spade fuse . 5% other misc faults. Here is a little "ballpark" test of your Multi-tap antenna system-This has got me out of trouble many a time: Set antenna and radio to the frequency you wish to test.-Turn up radio to about 3/4 volume. Unscrew coax connector from radio--you should now only hear some low level "hiss". Plug the middle contact of the coax connector back into the radio-You dont want to push it all the way home-Only the centre pin must be connected, the outer screw thread must be clear from the radio.--Noise level through your speaker should jump dramatically. You should now hear plenty of loud static coming from the radio. Now here is the important part-Now push the connector all the way home and touch the outer thread on the radio--If all is well ,the static should get about 25% louder, if it gets a bit quieter your antenna is not set up properly--If it goes very quiet, you have a short circuit in your antenna or coax system. This is only a general test only, but it may help you to trouble shoot your problem. Comments:
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| I cant seem to receive anything, All I can hear is "Hash & Noise". |  | Background "Noise and Hash" is quite normal on a HF radio receiver---The latest model Barrett (2050) & Codan (NGT) both have noise reduction systems which improve things a little, but are not a miracle cure. If you can only receive a signal from a car basically parked 50 Metres from you, the problem will probably be: *Short circuit in antenna or coax system. - Common Fault. *External electronic noise generation--Common culprits are Battery Pulse, Antirust Systems, Cheaper Solar Regulators, and Fridges - All of these devices will need to have a switch fitted inline so they can be turned off while using the HF radio. - Common Fault. If you cant receive a signal at all from a car parked 50 M from you, you probably have a faulty receiver. |
| Can you modify my radio to do.....?? |  | Yes, I am happy to do firmware upgrades and other mods which keep the radio within it's ACMA type approval or Ctick specifications(ie-keep it all legal for normal 4WD use). There are some Amateur radio (opt A, TXE etc) options available which take the radio outside these guidelines.---I will need to see a copy of your relevent licence if you wish to purchase one of these options....no exceptions!
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Can you supply programming software to suit my radio?
|  | I cannot supply radio programming software-It is not freeware, and the radio manufacturers closely guard their copyright of it.
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