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Antenna for SW DX listening.

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Sunyjim

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Ontario Canada
I'm getting back into shortwave listening.
It's been a while and wow the landscape has changed on the dial, no more BBC, Netherlands, DW, HCJB, VOA, Christian Science Monitor. I've have Found China, Taiwan, lots of WWCR and WWFR but I'm working to get a long antenna up to hear the english stations that are not aimed at my Southern Ontario Canada location. I mostly listen in the evening so the plan was optimize the antenna for 60m, 49m, 31m bands

So far I have stretched as much 14 guage solid coated copper wire up in my back yard as will fit.
To isolate the wire I used drilled wooden blocks for both ends of the wire, and stretched it out with rope from the back of the house (25ft up) to a clothes line post (8ft up) so it is gradually sloping down to the NE, I added a heavy screen door spring to take the stress off the wire at one end. The length ended up being about 45ft

That wire is soldered to the center conductor of RG6 75 Ohm cable that i had, that I ran into the house through the basement. (no balaun or tuner as of yet)
I ran the cable through a grounding block with another coated 14 gauge wire to a cold water pipe ground.
then to my External 75 ohm antenna jack on my Grundig Satellit 500.
I used a coax connector for the ground and at the radio because I found a "coax to euro-tv adapter" to go into the radio

Now the problem, The signal is quite weak (weaker than the built in 4ft antenna) but the ground connection it makes the signal much stronger on par with the antenna with less overall noise than without the ground, especially on the lower bands. But it does add a lot of buzzing ( cold water pipe also is also used to ground the breaker box, and motor for the gas hot water heater )

Is there any suggestions to improve my reception? Should I cut the wire in the middle and make it a dipole? Add a balaun? stick an 8ft copper stake or pipe in the ground to ground the outer shield of the coax?
 

a29zuk

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599
Location
SE Michigan
Even though the cold water pipe is grounded its ground point could by far from the receiver and is acting as a counterpoise for your antenna . Combining this with being connected to other components(motor, water heater) might be why you are picking up a lot of local noise. I would unhook the ground connection to the water pipe. Then use the 8ft ground rod as an isolated ground for both your receiver and the shield of your coax with your connection point at the receiver. The ground rod should be as close to the receiver as possible. Remember, every home station has unique properties so someone else could give a different solution. Experimenting with different antenna/gronding situations at your location is the best way find the solution.

Good Luck,
Jim
 
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Sunyjim

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Nov 11, 2011
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Ontario Canada
No ground on Radio, location of ground stake.

My Grundig Satellit 500 doesn't have a ground post or jack, so does it make a difference which end the ground is closest to?

I have two options
Close to the radio: Where I brought the coax into the house I added a grounding block. ( it's about 40ft from the antenna but only another 10ft to the radio) and instead of the wire to the cold water pipe I could sink an 8ft rod outside the house and run a short wire to that. Where my cable came in on the east side of the house it's shaded and not dry but it's not wet or anything either.
Near the Antenna:My other option is the ground rod at the other end of the wire, close to the antenna. I could add a coated down wire turning the antenna into an inverted L, and connect the coax at the bottom, and the shield to an 8ft copper pipe into potentially wetter ground there. North east corner of the house, almost always in shade and mossy wet most of the time.

I was reading about doing the water drill method to put the 8ft pipe in the ground which I guess would allow me to moisten the ground if it got really dry.
 

Sunyjim

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Nov 11, 2011
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Location
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No, not a balun, you need an "unun"!
See here in the RR Wiki...
MØUKD - 9:1 Magnetic Longwire Balun ? - UnUn !
Works well for me with a 66ft short "longwire". A longwire should really be longer than a wavelength. Easy for 10metres, not so easy for the tropical HF bands on 120metres!
So maybe a ground rod and a Balun?
Sorry for the newbie antenna questions,
Now I'm not great with building stuff, but I have a friend who could help, is it still a 9:1 considering I'm using RG6 75 ohm wire and my radio for some reason has a 75 ohm connection rather than a 50 ohm?
and the wires in the link picture seem to be bare copper, doesn't the possibility of them touching do anything to the design? can I use plastic coated wires?
 

majoco

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Dec 25, 2008
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New Zealand
The "copper" wires are coated with an insulating layer specifically for coil winding - any insulated wire will be fine - I stripped out an old computer printer cable and used the thin wires from that - multi coloured makes life easier! For receiving, the difference between 75 and 50 ohms will not be noticeable - the impedance of the antenna is variable over the frequency range so the transformer ratio is a "best fit" compromise. The sleeve of the plug that goes into your radio should go to braid of the coax cable, the tip to the centre. The ground spike should ideally be at the antenna end of the coax under the antenna, but not connected to the braid of the coax, only to one side of the antenna winding of the "unun" as per the webpage diagram. This should help in preventing noises from electrical equipment in your house being heard in the radio.

Have fun!
 

majoco

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Dec 25, 2008
Messages
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New Zealand
I wouldn't bother with the minute length of coax from the toroid to the SO239 socket though - and make the end that goes to the red terminal just a little bit longer so that it reaches!
 

AC9BX

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Joined
Jun 11, 2011
Messages
289
Location
Lockport, IL
I wouldn't bother with the small piece of coax either. I'd just try to make the whole thing smaller, keeping leads shorter. I salvage enameled wire from old power transformers, chokes, CRTs, motors, etc. With today's copper prices the work of dismantling these things is worth it. There's always scraps of computer network cable or something like that lying around.
 
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