Quiet Wire Antennas

[xanderham8]

Anyone here can tell me what is the most quiet wire antenna for HF, that is not susceptible to atmospheric interference etc., ...I am using a locally made 2.5kW coax 1:1 balun, an Andrew C2FP coaxial cable and a Yaesu FT-707 HF transceiver...I would like to operate in 15, 17, and 40 meter bands.... is there any configurations need to be follwed etc., any advice or suggestions from the experienced hams...Many thanks.

 

[Don_Burke]

Loops tend to knock some of the noise down, although a good chunk of the noise is following the same path your desired signal is, so there is a limit to what an antenna can do.

 

[ka3jjz]

You forgot one very important piece of information; what antenna are you currently using? A vertical will almost certainly be a noise magnet. Every antenna on HF is going to pick up some noise - atmospherics (say, from a thunderstorm or a heavy snowstorm) really can't be avoided completly.

If it were me, and I had the space, I would consider a Carolina Windom or G5RV. For antennas less sensitive to man made sources,consider the PAR antennas, fed through a good quality coax switch. I have yet to hear of anyone saying anything bad about the PAR - they seem to enjoy quite a good reputation. Loops are also another option.

73s Mike

 

[Highlander_821]

I just built and installed a W5GI "mystery antenna." It is performing amazingly. I have <2:1 SWR on 80, 40, and 20. The other bands I need my tuner. It picks up quite a bit less static than my vertical. With 100 watts I'm talking all over North America, and can hear DX stations, but haven't been patient enough to work through the pileups.

I have it mounted in a slight slope angle, with one end at about 50 feet, the other at about 30-35 feet.

It was fun and easy to build. The only expensive (relatively) item was 300 Ohm ladderline--that was about .30 a foot. The rest of it was all stuff I had---galvanized fence wire, RG8X coax, some 1/2 inch pvc for the insulators, and some 1/4 inch nylon rope for hoisting it up into the trees.

I am going to build an off-center fed dipole (windom variation) this weekend, and hope to get it up and be able to play back and forth between the two.

 

[ka3jjz]

Highlander, do you have a link for this antenna? 73s Mike

 

[k8mcn]

http://www.w5gi.com/mysteryantenna.htm

 

[mfuller1950]

How about a standard coaxial bazooka for specified frequencies.

 

[W5JLF]

I put up a Buckmaster 7-Band OCF Dipole (http://hamcall.net/7bandocf.html) on 02-14-08 and have talked to all parts of the U.S. and 10 contacts outside the U.S. Three times to the ARRL DXpedition on Ducie Island in the South Pacific on 12m & 17M. Also to Williams Lake, BC, Canada on 17M & 20M and Trujillo, Venezuela on 20M. All of this with only 100 Watts.

Joe, KK5JLF

 

[Highlander_821]

I am going to make one that is 137 feet overall, with a feedpoint at 27.4 feet from one end. I will feed it with a 300 ohm ladderline. It will be installed as a sloper most likely. I already have the fencewire ( I bought a 1/4mile spool for 15 bucks, lol) And I have the ladderline left over from the W5GI. I worked that Ducie Island station on 17 today on the W5GI, as a matter of fact , 59 on 100 watts.

What an awesome SWL antenna. 49 and 31 meters are rocking on this thing.

 

[ka3jjz]

Ah but while everyone is raving about these antennas, just how quiet are they? Do they reject man made noise sources (which is part of what xanderham8 should have asked in the first place)? Remembering, of course, that atmospheric noise sources are very hard to ignore, as has been written about earlier....73s Mike

 

[Highlander_821]

What I notice most is there is very little static on the W5GI. Of course no antenna is going to get rid of noise generated by poorly tuned equipment, wideband SSB, overmodulation, etc. Same thing with atmospheric noise.

But since I got into radio, static has always been the worst kind of noise I've had to deal with, and when I switch to my vertical on HF, there is usually a bunch of static noise during the day, and switching to the W5GI is a pleasure, signal comes up, static goes down. Add the auto-notch and a little AF DSP, and I'm usually in good shape.

 

[zz0468]

You have to keep in mind that for noise and static that's in the far field of the antenna, ie coming in via skywave and groundwave, anything that reduces the static is also going to reduce signals. This isn't necessarily bad, but that may also indicate that it's not an efficient radiator for transmitting.

Any directional antenna that can be oriented away from some bothersome noise source would be useful. Another option is to use receive only antennas like loops and beverages, and switching to something else during transmit.

Low noise receive only antennas like loops and beverages can require either a preamp, or in the case of a beverage, lot's of real estate.

If noise is really a problem, you may consider getting an active noise canceler. They make the difference between me working dx on 160 and 80 meters, or watching tv in frustration.