night prowler
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Building a shortwave antenna
Hello fellow radio nuts, Now my 11 meter antenna is sorted and working a treat I have turned my sights on my shortwave antenna. At the moment I have a wire di-pole in the attic, It was 30foot of wire each way running around the attic but all I was getting was 30+ of noise so it has been cut down to about 6 foot each way and now it works ok. I was always the impression that the longer the wire the better. I used to have an old Eddystone 840A valve receiver years ago and it worked great on a long wire but now im using a cheap plastic Realistic DX 394, Could this be the reason for the noise? I know it's not the best HF radio but until I can afford something better it will have to do. Any suggestions? Cheers all...Rich
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20/Jun/2011, 11:23 am
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Ivy Watts
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Registered: 05-2011
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Re: Building a shortwave antenna
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Hello Rich ...
When you have done a couple of mods to the 394 it can be quite a fair receiver. I have one here that I use when I don't want to fire up my Yaesu 767 Transceiver.
The first thing is to cut out all the stuff that gets into the Receiver through the plastic case. Easy Peasy - 5 minute job. Unscrew the telescopic antenna, and throw into skip, then just get some Baco-foil Kitchen roll, and take the top and bottom off the 394 and line them inside with the foil - (I actually just laid it loose over the chassis sides and then re-fitted the case (not recommended, as it could short out something!) ... just make sure that the foil connects with the chassis somewhere.
Next job - Anti-chuff it !! As you tune the receiver it 'chuffs' on each tuning step. To stop this, and get 'smooth' tuning, you just need to clip out a wire.
If you look at the top side of the circuit board, there is a quite big white connector which has about ten or twelve wires going to it ... Its almost in the middle of the board. Get a pair of wire cutters (I used nail cippers!) and cut out the only PURPLE wire that goes into that connector. Job done !!!
One I did that was really not a big success - I pushed 'Blue Tac' into the recesses in the back of the tuning knob, and then kept pushing in lead fishing weights, until no more would go .... I thought this would give some 'solidity' and 'feel' to the knob when spinning it, but I don't think it made much difference.
There are loads of other mods on the Interweb, but thats all I have done to mine, and it hears almost as well on the same antennas as the 767, or my Grundig G3 Globe Traveller.
Kind regards,
Terry
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26 FB 89
Kenwood TS520SE HF Tx
Yeticom Optima 10/11/12 Mtrs Tx
ICOM PCR1000 - 100 Khz to 1300 Mhz Rx
5/8 Wave 'Venom' Silver Rod
Wire dipoles 40/20/15 Mtrs
M0AQC Digital Modes Interface
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20/Jun/2011, 1:31 pm
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night prowler
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Re: Building a shortwave antenna
Cheers Terry,
I already done the anti-chuffing a while back and it made a big diference when using it. I already threw the telescopic antenna over the neighbours wall. I'll try the foil thing later but I'll make sure im sober when I do it! What does it do anyway?
I bought my 394 second hand years ago and it has a mod on the back for connecting it to a computer I think, It's a phono plug but I have never known what to do with it, Anyone got any ideas about this?
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20/Jun/2011, 4:07 pm
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Ivy Watts
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Re: Building a shortwave antenna
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The foil mod, is the same as having the receiver in a steel case. It protects the receiver from picking up local noise from computers, etc...
Regards,
Terry
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---
26 FB 89
Kenwood TS520SE HF Tx
Yeticom Optima 10/11/12 Mtrs Tx
ICOM PCR1000 - 100 Khz to 1300 Mhz Rx
5/8 Wave 'Venom' Silver Rod
Wire dipoles 40/20/15 Mtrs
M0AQC Digital Modes Interface
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23/Jun/2011, 7:52 pm
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2fb105
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Re: Building a shortwave antenna
saw your post don`t know if this helps but i have a multimode 2 with a stereo type plug on the back and its for a external freq counter could that be what it is
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30/Jun/2011, 12:22 pm
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mikefox whiskey
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Re: Building a shortwave antenna
Hello night prowler, my suggestion would be to put your antenna outdoors rather than in the attic, a long wire in the attic will be affected by all the utility wiring and the electrical items in the house and the signals will be attenuated by the roof itself.
The longer the wire the more atmospheric static you may receive also. If it's just for general Short wave listening one simple wire rather than a dipole may work better for multiband listening.
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30/Jul/2011, 8:00 pm
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night prowler
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Re: Building a shortwave antenna
Cheers Patrick. I have decided against the HF Discone now. I have a V style wire di-pole in the attic for HF, It's about 7 or 8 feet each way and to be honest it works really well, You know what they say, If it aint broke dont fix it. Still need a discone for the scanner tho. I might experiment later on with different size di-poles for HF.
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20/Aug/2011, 3:17 pm
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