Codan 8528a
Submitted: Friday, Jun 09, 2006 at 22:49
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G&R
G'day all. I have recently acquired a old Codan 8525a, which I would eventually like to take out bush with me. However I am having some issues with the transmission. The reception works better than expected, I can hear from the Top End to
Adelaide and all in between. But I can't seem to get a signal out. The unit draws about 4A when trying to transmit, (the manual says it should be about 10A).
Is this a common problem, or does any one have any suggestions?
Cheers,
Greg
Reply By: Willem - Friday, Jun 09, 2006 at 23:26
Friday, Jun 09, 2006 at 23:26
Could be DRY JOINTS. Now I am not sure exactly what that means but have been told so by Radio experts. I have an even earlier radio than yours(6924). They really need to be serviced once a year. I can also receive from all over but have to rely on skip to transmit successfully
Cheers
AnswerID:
177766
Reply By: Member- Rox (WA) - Friday, Jun 09, 2006 at 23:57
Friday, Jun 09, 2006 at 23:57
What size aerial?
std or a short 1?
I presume auto tune.
The barretts have a power output setting Hi/Low not shore of codans.
AnswerID:
177772
Reply By: Mike Harding - Saturday, Jun 10, 2006 at 08:04
Saturday, Jun 10, 2006 at 08:04
Could be many reasons - check your antenna system _very_ carefully and, perhaps, try a length of wire as an antenna - someone will know what length you need for the
VKS737 frequencies.
In the meantime, in case you don't have the manual:
www.reidsradiodata.com.au/codancolumn.htm
Mike Harding
AnswerID:
177790
Reply By: Peter 2 - Saturday, Jun 10, 2006 at 08:05
Saturday, Jun 10, 2006 at 08:05
The actual peak power drain will get up to around 20 -25 amps, Codan used to supply a 32A cartridge fuse in a large holder used for a switchboard to avoid power losses.
You also need very large wiring to the transmitter, the supplied cable is about the size of jumper leads and you can't use anything smaller.
check ground connections of both transmitter and aerial, they ned to be spotlessly clean too.
what sort of aerial are you using?
AnswerID:
177791
Reply By: Footloose - Saturday, Jun 10, 2006 at 08:47
Saturday, Jun 10, 2006 at 08:47
A quick indication is the transmit light. It should be
bright red when you speak into the microphone. If not, the fault is either in the
Wiring
Radio or
Aerial.
I'd get the set looked at by a techo. You don't want to be trusting your life to something that isn't working or reliable.
AnswerID:
177794
Reply By: G&R - Saturday, Jun 10, 2006 at 09:15
Saturday, Jun 10, 2006 at 09:15
G'day all, thanks for all the ideas! I am using a tapped bushcomm firecracker antenna. I have set it up as a portable system.
The Tx light does flicker when talking, and is quite
bright when I try to selcall.
I'll have a look at the joints, in particular the antenna connection. I have also heard that the radio will automatically reduce the power if there is an antenna problem.
It will certainly get a trip to a qualified tech before I rely on it!! (Maybe sooner rather than later!)
Thanks again,
Greg
AnswerID:
177796
Follow Up By: signman - Saturday, Jun 10, 2006 at 12:49
Saturday, Jun 10, 2006 at 12:49
Are you using the set vehicle mounted- or as a base station.?? I f not vehicle mounted, you may need a good earth stake!!
FollowupID:
433941
Follow Up By: G&R - Saturday, Jun 10, 2006 at 13:40
Saturday, Jun 10, 2006 at 13:40
Signman, it is not vehicle mounted. It is self contained in its own container. I was using a 12" peg as an earth. Is that suitable?
Greg
FollowupID:
433943
Follow Up By: VK3CAT - Saturday, Jun 10, 2006 at 14:25
Saturday, Jun 10, 2006 at 14:25
Greg, with your setup as described you will have problems unless you really know what you are doing. It sounds like the radio is transmitting into a mismatched antenna and is reducing its output power inorder to protect the output transistors.
Probably the only simple way to opearte completely portable is to use a resonnant dipole antenna which doesn't require an earthing system.
There are plenty of ways to make a potable setup work well but some RF knowledge is required as well as testing instruments.
Note that for
VKS737 & outpost station licence use, the antenna system is supposed to be mobile / portable.
Give me a yell if you want more information.
Cheers Tony
www.qsl.net/vk3cat
FollowupID:
433947
Reply By: Darian (SA) - Friday, Jun 16, 2006 at 14:04
Friday, Jun 16, 2006 at 14:04
Yep re the above - age of the unit doesn't have to be a factor - I had a 25 year old Tracker Scout - bl.....dy brilliant radio -talk only - no selcall, but a top rate signal in and out - still going with the new owner - your Codan may just need a good tidy-up. Tap antennas are the best (after a tuned wire) and very reliable. If it needs new parts and labour though, the subject of good money after bad rears its ugly head.
AnswerID:
178786