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Earthing the shack
Posted: Tue Sep 30, 2008 2:01 pm
by Danger Mouse
Hi Meg.
I like to earth my shack four ways.
An Electrical Earth for the power, which should be part of the earth wiring in Australia and NZ anyway.
Then I provide an RF or Signal Earth. This I raise by fixing a section of square racking material - unpainted and unanodised - to the bottom of the radio bench, and drill holes every 25mm along it's length to take self tapping screws. I then provide a seperate lead from every Earth connector on the transmitter(s) Receiver(s) and Antenna tuning Unit(s) to that bar. One Earth lead is then feed out of the shack to a ground stake. I like to use a proper earth stake at least 6 foot long, which I get from Bri Tech in wangara, but any electrical wholesale house will have them (eg: MM Electrical, is another example). I drive the stake in until about 2 inches is left above ground, and clamp the wire from the earth bar to the stake. This removes all stray RF from the shack and prevents me getting bitten by RF. Which is distinctly OUCH time! You can test for stray RF with an ordinary LED and wander leads.
Then there is the grounding of an earth mat if you are using vertical antennas for HF, and finally there is the spark arrestor earthing for Lightening strike - but both these need to be seperate discussions.
Ps: do not use the houshold earth for RF Earth. It causes the Footy addicts to complain when the TV picture suddenly says CQ CQ CQ....
Posted: Tue Sep 30, 2008 4:16 pm
by VK6LD
VK6ZMS wrote:
Make sure you take the paint off the star picket.
I meant to mention that mine is a galvanised star picket, 1.8m long with about 3 inches sticking above the ground.
Meg: you might want to try a longer star picket.
Posted: Tue Sep 30, 2008 6:14 pm
by meg
Hi all,
The latest installment isn't such good news unfortunately...
The star picket is about 2 meters long, it just won't go any further into the ground - we tried a number of locations for it, but there's granite under the gravel, it's just not possible. I did file the paint off the picket though before we put it in
So, armed with a longer coax cable, I've plugged in the antenna, fitted a new fuse, and finally tried powering it on but get a big nothing from the Yaesu. And it appears that noone in Perth services Yaesu amateur radio gear (though I'd be most pleased to hear if someone can tell me differently!). For Yaesu to check it out would mean it has to be sent to Melbourne. Probably as cheap for me to fly over with it as luggage!
Does anyone have any suggestions other than Melbourne? Things to check on it or other (more local) peeps who might be able to look it over?
Cheers
Meg
Posted: Tue Sep 30, 2008 6:35 pm
by robbage
Remind me what model it is again?
I have a collection of service manuals and diagrams for a bunch of transceivers.
Posted: Tue Sep 30, 2008 6:37 pm
by meg
It's an FT-990.
I found a bunch of docs here
http://www.n7tgb.net/pages/radio/yaesu_documents.htm
but the Service Manual is waaaaay over my head, and the Operating Manual is written assuming the unit is working

Posted: Tue Sep 30, 2008 6:42 pm
by robbage
I have the circuits for it .. and downloading the service manual from that link. Might be something easy. I see there are two fuses for the AC line.. how many can you find?
Edit:
OK three fuses. Looks like one panel mount and two internal. The diagram indicates you can plug in a DC supply such as a car battery or external 13.8V supply. It would be handy to know if you are able to plug something into that and see if it works. I'm guessing it's one or both internal fuses.
Posted: Tue Sep 30, 2008 6:44 pm
by meg
Thanks Robbage!
Just the one - in a screw in socket on the back plane.
Where's the other?
If it helps to think of possible causes - the rig came from an enthusiast who took good care of his gear, but it's been in storage at his daughter's place for a fair while.
Posted: Tue Sep 30, 2008 6:45 pm
by Nick
oops meant to pm
Posted: Tue Sep 30, 2008 6:49 pm
by robbage
See my edit above
Posted: Tue Sep 30, 2008 7:00 pm
by meg
robbage wrote:
OK three fuses. Looks like one panel mount and two internal. The diagram indicates you can plug in a DC supply such as a car battery or external 13.8V supply. It would be handy to know if you are able to plug something into that and see if it works. I'm guessing it's one or both internal fuses.
OK, I've taken the top off and honestly - the chassis is full of cards - I can't see a thing inside it. Have sent you (and Nick) a PM
edit:
Here's a photo of the internals
http://www.flickr.com/photos/sonic_echi ... 6/sizes/o/
Cheers
Meg
Posted: Tue Sep 30, 2008 10:55 pm
by Tyranus
woohoo go meg pulling apart radio's already!

Star Pickets
Posted: Wed Oct 01, 2008 12:40 pm
by Danger Mouse
Meg,
If it will not far down, owing to ground rock, you can always put more pickets in the ground and wire them together. You can also put them in at an angle so that more is in the gravel. At our bands and powers the Radio Frequency Currents will not flow deep in the ground.
And good luck with the fuses....
We told you this hobby was fun!
Posted: Wed Oct 01, 2008 1:15 pm
by robbage
Well after checking the internal fuses we discovered that it has no internal power supply. The original owner powered it from the external DC socket

Nice to meet you Meg and S. (Good luck in November, S!)
Posted: Wed Oct 01, 2008 6:01 pm
by meg
Thankyou again Robbage - yep, the big gap where the internal power supply would be was a big giveaway and I'm sure the radio enjoyed the trip, but boy did I feel stoopid!
We've got the power supply, now just trying to get the almost perfect plug into the right shapes (filing squares into rounds kind of thing).
Cheers
Meg
Posted: Wed Oct 01, 2008 6:29 pm
by robbage
meg wrote:... but boy did I feel stoopid!
There was no way to know it didn't have a power supply just looking at it.
meg wrote:We've got the power supply, now just trying to get the almost perfect plug into the right shapes (filing squares into rounds kind of thing).
Did you get the power supply from Jaycar?