One for the HF and Megapulse experts

G'day David,
What radio is he using?? I have a mate with an old 7727 crystal Codan. He gets a loud whistle thru the radio with the megapulse on- but disconnected no probs. receiving or transmitting. I have worked him from Sydney all the way up the Canning. The long wire option definately increases performance- however there is some debate as to the direction it should be sloped. I think the higher end of the wire should be away from the receiving station- giving a better skywave.

David,
Just had a brainstrorm. Is the Audio Mute turned OFF. With the 8525 the mute is enabled at switch on- and should be switched OFF by pressing the Mute Off pad.
Also, has he got good earth connections. As you are aware the antenna should have a good clean earth- but there is an earth connection on the back of the radio with should have a reasonably heavy wire to a clean chassis connection??
Also, enough grunt in the battery?? I guess you've heard some weak signals on the VKS sessions- but when the users start the engine the signal strength increases dramatically.
But I still agree- the Megapulse WILL affect performance mainly on receive.
If (or when) you resolve the problem I would be interested.

A HF Radio earth is equally as important as the antenna. Generally, a thick wire just isn't good enough (unless it is less than 300mm long). If you are relying on the DC power cable negative for an RF earth, you will be disappointed with the results.
Technically a HF antenna needs a counterpoise, similar to how some UHF antennas need a ground place.
Because RF energy travels along the SURFACE of a conductor, having a thick wire (good for lots of DC current) isn't up to the task of being a good RF ground conductor.
This is why the Codan 9350 autotune comes with a flat earth braid, it is all dependant on surface area!!
When I installed my old tapped whip, I used a 25mm copper strap to connect the antenna base directly to the chassis of my 4x4. This made it work 50% better that relying on the metal to metal connection from the bullbar to the chassis.

For a portable set, I would recommend using several (at least 3) long insulated wires, radiating out along the ground from the ground connection of the radio and/or antenna tuner. For portable use, I would also get a Bushcomm broadband wire antenna. You connect it to the radio, sling it up over a tree and away you go without needing a tuner!

PLUS, one other thing. We are currently at the bottom of the 11 year sunspot cycle. HF conditions are generally crappy at the moment, but they will improve!

Check out www.ips.gov.au for info on HF radio propagation. At the moment, there is a HF radio warning with degraded HF propagaion conditions expected.

Welcome to the world of HF communications!!

Tell Bruce to make sure that his aerial base is properly earthed to the bullbar or the battery negative. Also the poweroutput can be very roughly determined by watching the red tx led on the set.

Three cheers for Footloose. A champion to deal with and ever helpful on the codan yahoo forum.

Can't wait for my new (2nd hand) 9323 to arrive from him, and he's kept me posted as to it's progress every step of the way.

I even actually believe the last bit he said because at his prices he can't be making that much for himself. One of the other better known Codan dealers in Vic's price on the same 9323 and antenna combo at Wandin was exactly $1000 dearer on a good second hand unit. And Footloose patiently put up with my tyre kicking for a few months before I bought mine.

Footloose's web page

And no he didn't ask me to give him a plug. Credit where credits due as far as I'm concerned.

A heartfelt thanks very much Footloose, you can stop blushing now.

For those that are interested the codan forum can be found here and it is full of info. There's possibly a Barrett one too but I've not bothered looking even though they also make good gear, I already owned a Codan when I found it.

Dave

I heard Bruce log in to Alice Springs today- his first contact with a VKS737 base since he left. I spoke to him at 8.30pm when the scheds had finished. He had a good copy on me but I had a pretty marginal copy until his last over, so I don't know what he has done to solve the problem.

By his reluctance to go to Channel 1, I suspect he is running a wire rather than a multitap, so maybe an antenna, cable or spring base problem. His battery was running down and we had to call it quits but I will listen in for more news.

Hey footloose..just an update....

I have been listening in to the scheds daily and chatted with some of the operators afterwards. We all copy Bruce way way way down low on every single contact.

I threw an old inverted V I had for 8 MHz up into a tree (that took some doing) and managed to get a reasonable contact on him such that some overs were readable. His is definitely consistently the lowest signal on the air, no matter who he is talking to, so he does seem to have a problem, just don't know what it is.

He says all of the electrical and antenna connections check out OK.