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eHam Forums => SWL (Shortwave Listening) => Topic started by: KC9EJG on March 14, 2012, 05:47:50 PM



Title: What is the best SW antenna ?
Post by: KC9EJG on March 14, 2012, 05:47:50 PM
Just thought I would put this question out there to see what kind of response I would get.

     What is the best SW antenna?

I have a Icom R75 receiver.


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 14, 2012, 06:11:08 PM
RF Systems DX-1 Pro Mk II.



Title: RE: What is the best SW antenna ?
Post by: WB9YCJ on March 15, 2012, 01:07:35 AM
One that is immune or almost immune from vertically polorized man made noise.
Suggestions?................


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 15, 2012, 07:23:03 AM
One that is immune or almost immune from vertically polorized man made noise.
Suggestions?................

No antenna, whether horizontally or vertically polorized is immune from man made noise if it is in a noisy location. ;D

73,

Fred EI4GMB


Title: RE: What is the best SW antenna ?
Post by: K0OD on March 15, 2012, 09:27:59 AM
Quote
What is the best SW antenna?

Award winning dumb question.

End of thread


Title: RE: What is the best SW antenna ?
Post by: 2E0OZI on March 15, 2012, 10:23:55 AM
200 feet of wire over the tops of all the trees in an apple orchard worked for me. Then again I lived in The Bush.


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 15, 2012, 03:15:59 PM
Quote
What is the best SW antenna?

Award winning dumb question.

End of thread

I think KC9EJG was just looking for opinions. True, there are many...... ;)


Title: RE: What is the best SW antenna ?
Post by: KG4NEL on March 15, 2012, 04:12:19 PM
The one that lets you hear the station you want to listen to.


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 16, 2012, 04:40:03 AM
Seems there aren't too many opinions out there after all?


Title: RE: What is the best SW antenna ?
Post by: KC9EJG on March 16, 2012, 05:22:29 AM
I am going to ask for my money back. Some of you are very crude.


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 16, 2012, 07:04:40 AM
Don't let it bother you Richard. It was a fair question.

Best of luck.

Fred EI4GMB


Title: RE: What is the best SW antenna ?
Post by: K0OD on March 16, 2012, 11:02:23 AM
I was the only one who was rude.

The others didn't answer because your far-too-brief question is unanswerable. Eham has some very technically savvy hams, often with advanced degrees and long experience in various branches of engineering. Many here have decades in the hobby. Some have decades in military and government communication. But you have to provide a well-crafted question. Otherwise you're wasting their valuable time

Best SW antenna? For DX or stateside or some combination?
Best SW Antenna? SW meaning 2 MHz, 15 MHz? 30 MHz or some combination?
Are you restricted in some way from putting up towers of say 200' ?
Is money a factor or are you building a government installation?
For lower bands, long arrays of wires can approach being "the best." Do you have a straight run of say 2000'?
Since you are a ham, do you want to also transmit on this "best SW Antenna?"


Based on the few molecules of info you've provided, I'd suggest what gov't and commercial stations often use... a log periodic yagi, rotatable and up on a thick tower about 80' to 150' depending on your favored frequency.  Better to use two towers: A log periodic at about 70' for 15 to 30 MHz and another one up about 150' for 3 to 15 MHz.  

While that's not "the best," it's within the financial means of many hams/SWLs... willing to spend about $100,000. (best to find land zoned industrial or farming).  

==========
Personally, as a very casual SWL I like the long random hunk of wired draped over the trees approach.


Title: RE: What is the best SW antenna ?
Post by: GM6WCF on March 16, 2012, 11:56:49 AM
So he knows it was rude, perhaps just the smallest display of repentance overlaid with a dollop of self justification. K0OD typifies the unpleasant and arrogant and deserves to be ignored. These folk may have existed thirty years ago, I'm sorry they haven't died out. 
Perhaps what is needed is a NEWBIES Forum where sarcastic Elmers are named, shamed and banned. How about that moderator?
That sort of response is not helpful and not needed. The question was innocent and honest and didn't need the big boot response.
I followed this link because I thought it could prove useful to me!!!!!! I'll think twice before asking for help on this site.
How about my money back.
Disgusted Scotland


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 16, 2012, 01:51:53 PM
Sometimes those of us who are more experienced can be a little dismissive of others.
Being rude or condescending does not help.
Having said that K0OD has given some valid reasons why the OP's question could not be answered.
It is now time to move on.......

73,

Fred EI4GMB


Title: RE: What is the best SW antenna ?
Post by: GM6WCF on March 17, 2012, 06:54:42 AM
KC9ELJ
Illegitimi non carborundum
Here's a link to a free .pdf file that I found useful.
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=16151

Dave B


Title: RE: What is the best SW antenna ?
Post by: AB4TI on March 17, 2012, 07:05:02 AM
A 25 to 50' wire outside the shack and a decent ground is probably the least expensive and most effective way to go if you have room. A pre selector can help tune the wire for maximum effect if you have the funds. Depending on which SW radio you're using too long a wire will overload some less expensive, poorly designed radio's Hope this helps.
73 de Dan AB4TI


Title: RE: What is the best SW antenna ?
Post by: VE7SHM on March 17, 2012, 07:05:15 AM
Well for me so far the T2FD has been the best general antenna i have used with my radios for SWL .Its so quite i can use a preamp which give me 20 db but hardly raises the noise level ,I took my long wire down and will not be putting it back up, i have a para end-fed SWL i find it to noisy .


Title: RE: What is the best SW antenna ?
Post by: K0OD on March 17, 2012, 10:00:21 AM
Quote
"preamp which give me 20 db but hardly raises the noise level "

QRN is a signal too. I can think of very, very few situations where adding an untuned preamp to a tenth-way decent receiver will make a signal more copyable.

Reminds me of when I was a dumb 12 year old and figured that hooking up the family hi fi amp to my dreadful novice receiver would help pull in DX (after all, the hi fi amp had a bazillion dB of gain, right?).


Title: RE: What is the best SW antenna ?
Post by: KC9EJG on March 17, 2012, 10:09:35 AM
Thank You.


Title: RE: What is the best SW antenna ?
Post by: VE7SHM on March 17, 2012, 01:34:55 PM
Thank You.

The t2fd works great by it's self and are very easy to make .And way quieter than any random wire good luck ......

http://www.radiohc.org/Distributions/Dxers/ttfd2.html


Title: RE: What is the best SW antenna ?
Post by: KAPT4560 on March 17, 2012, 05:10:17 PM
 I find that a 50' or 100' spool of 16ga stranded random long-wire works for my purposes. Most auto parts stores sell a spool of this wire for cheap. I have the room for an inverted-L across the roof (E-W) and down the side of the house or a (N-S) sloper from the house roof to the garage roof. Both give good omni-directional reception.
 As mentioned previously a good ground may cut noise and increase gain particularly on lower frequencies, except if this is an AC-DC boatanchor (don't ground this chassis).
 Lightning protection is important to protect house and property and maybe equipment unless your antenna is run inside across the attic.
 A quality receiver with a good RF amplifier and preselector section can make DX listening much more enjoyable than a mediocre receiver. 


Title: RE: What is the best SW antenna ?
Post by: AD4U on March 19, 2012, 06:00:39 AM
Not trying to be a smart butt, but the "BEST" antenna would probably be a full size rotatable yagi for each frequency mounted on towers that are at least one wave length high.  This will be a rather costly proposition given the number of yagis and towers required and the size there of, especially on the lower frequencies.  Ever see a 3 element 1.8 MHz yagi mounted on a 555 foot tower (one wavelength on 1.8MHz).....

For good all around results a wire as long as possible and as high as possible will work very well.

Dick  AD4U


Title: RE: What is the best SW antenna ?
Post by: KE4VVF on March 20, 2012, 09:07:53 PM
The best antenna for me is my $50 102' G5RV @ 50' strung between 3 trees as a horizontal flat top.  Almost invisible and picks up weak stations very very well.  Had it @ 20' and it didn't work nearly as good for SWL, so what ever antenna you use height is truly the key.


Title: RE: What is the best SW antenna ?
Post by: K5OF on March 21, 2012, 02:58:14 PM
If you can not respond in a nice way or query as what his goals/situation presents than why respond at all except to flame the guy.  The fellow ham is interested in a serious response. And with maybe further clarification that he can provide maybe that would be the appropriate response. It does not need to be done by demeaning him or his question. Hams like K0OD need to be avoided. Smart @#$ comments need to be avoided. We are all here to help if we can. There is no such thing as a stupid question. If he needs help then provide it if you can. If not then stay out of the thread. I can not provide any help but I will participate in the thread as long as persons like K0OD want to demean a person and make another fellow ham feel like he can not ask a question without getting flamed. I will possibly have a question that might not be the brightest and if so I hope I get a response such as "Hey Ed, please tell else a little more?" Enough said Good luck KC9EJG and 73! Ed


Title: RE: What is the best SW antenna ?
Post by: K0OD on March 21, 2012, 04:57:06 PM
Hey, I ask dumb questions too. But I very rarely ask lazy ones.

K5OF, welcome to Eham. 


Title: RE: What is the best SW antenna ?
Post by: KC9EJG on March 25, 2012, 02:35:05 PM
To those of you who responded in a good way I say " Thank You " I am a very lucky radio operator. I have had a very bad stroke an it took two years to get back to some normalise. I am wanting to put up something that will do me a good job so I can use a Icom R75 in the sleeping area that I have. So 73's to all who tried to help me. Oh bye the way I have some brain problems trying to put things in the right context some times but being a jerk is not one of them. I am just thankful that God seen fit to spear me so that I might see my 1st grandchild born. Well I have rambled on so I will close.

     73's


Title: RE: What is the best SW antenna ?
Post by: VE7SHM on March 25, 2012, 07:11:46 PM
To those of you who responded in a good way I say " Thank You " I am a very lucky radio operator. I have had a very bad stroke an it took two years to get back to some normalise. I am wanting to put up something that will do me a good job so I can use a Icom R75 in the sleeping area that I have. So 73's to all who tried to help me. Oh bye the way I have some brain problems trying to put things in the right context some times but being a jerk is not one of them. I am just thankful that God seen fit to spear me so that I might see my 1st grandchild born. Well I have rambled on so I will close.

     73's

Oh every forum has a few bone heads pay them no mind ,As a few have suggested a simple random wire will work at my home there to noisy but maybe fine  at yours ............


Title: RE: What is the best SW antenna ?
Post by: EI4GMB on March 26, 2012, 08:24:16 AM
To those of you who responded in a good way I say " Thank You " I am a very lucky radio operator. I have had a very bad stroke an it took two years to get back to some normalise. I am wanting to put up something that will do me a good job so I can use a Icom R75 in the sleeping area that I have. So 73's to all who tried to help me. Oh bye the way I have some brain problems trying to put things in the right context some times but being a jerk is not one of them. I am just thankful that God seen fit to spear me so that I might see my 1st grandchild born. Well I have rambled on so I will close.

     73's

Richard,

I think you are credit to the hobby!
The way you have dealt with your disabilities and the way you have overcome adversity to maintain your interest in Radio is an inspiration to us all.
I hope to meet you on the air someday and I wish you the very best of luck for the future. Take care.

Kind Regards

Fred EI4GMB


Title: RE: What is the best SW antenna ?
Post by: N8YX on April 25, 2012, 07:56:32 AM
Put a log-periodic with 13-30MHz coverage at 70' or thereabouts...and run several multiband slopers (Alpha Delta DX-SWL or a homebrew equivalent thereof) from the apex of the tower - in the directions of interest. Say, Europe, Africa, South America, the South Pacific and Japan/China. Then connect them to a remote-controllable tower-mounted switchbox.

Works good at my shack; will probably work for you as well.


Title: RE: What is the best SW antenna ?
Post by: W0BTU on April 28, 2012, 07:03:15 PM
A Beverage antenna. Period.

http://www.w0btu.com/Beverage_antennas.html

You will hear LOTS of weaker signals that you won't hear on your random-wire, vertical, inverted-L, dipole, or most other antennas; not to mention a worthwhile reduction of unwanted signals and noise from undesired directions. If you have the space, you should consider at least one Beverage antenna, even just a simple single-wire Beverage.

Even a short Beverage antenna or a BOG is better than no Beverage! Although Beverages are typically at least one wavelength long on the lowest band, even a half-wave (or even shorter) Beverage antenna can very often out-hear any vertical or dipole antenna you might have.


Title: RE: What is the best SW antenna ?
Post by: AA1UY on July 17, 2012, 04:40:21 PM
One that is immune or almost immune from vertically polorized man made noise.
Suggestions?................

A small receiving loop. The Kaito KA33 is an inexpensive example. Due to their very narrow bandwidth,  noise is tuned-out.

At my QTH, I could no longer use my 4BTV vertical on or around 7 MHz (40/49 meters) as I started to get a consistent S7 noise all across that band. At first it was only in the evenings (right at 5:00 pm) but then it became pretty much 24x7. I replaced the 4BTV with an MFJ 1788 small transmitting (and receiving) loop and the S7 noise is gone completely (same co-ax feed-line).

Small loops are not very good for scanning due to the very narrow bandwidth (i.e. you have to tune them to the frequency (not just band) of interest in order to peak the signal), but that works to your advantage in noise suppression.


Title: RE: What is the best SW antenna ?
Post by: W0BTU on July 20, 2012, 05:47:19 PM
  Due to their very narrow bandwidth,  noise is tuned-out.

Really? How does that work?


Title: RE: What is the best SW antenna ?
Post by: KB2VWM on July 21, 2012, 11:27:48 AM
I've had a few different SW antennas over the years. A T2FD that I made, a few different long wires, and Alpha Delta Sloper.
They were all great on some bands, noisy on others and in some cases deaf on other bands.
Last year I decided to try something different and started looking into active antennas. My research led me to Wellbrook and Clifton Labs.
I ended up buying a Z1501 active antenna from Clifton Labs and I couldn't be happier, great reception on all bands and extremely quiet.

I've read great things about Wellbrook loops too but can't give first hand experience.

In any case I'm convinced that high quality active antennas are the way to go.


Title: RE: What is the best SW antenna ?
Post by: W8XLR on July 21, 2012, 07:20:13 PM
After extensive experimentation with my own antenna farm, Ive found for general SWL use my Drake R8A likes the 80 meter delta loop, fed with home made 450 ohm ladder line through a cheap MFJ-949E tuner best. I also have an Ameco PT-2 preamp in line which is sometimes usefull, sometimes not...

I agree that the beverage is the way to go for receive antennas, but I dont have the real estate for one...

"ILLIGITIMUS NON CARBORUNDUM", Thats allways been my motto!

73 de W8XLR/Phil


Title: RE: What is the best SW antenna ?
Post by: HFCRUSR on July 21, 2012, 08:58:46 PM
I am in a 10-unit apartment building on the top floor (3rd) here in western San Francisco and I am blessed to be permitted to run a swl antenna and a d130j discone.
I run a PAR EF-SWL but with a 100' #12 coated wire that is configured as a horizontal "L" and it is up at 40'. I am about a mile and a half from the ocean here, so as you can imagine, I have a lot of fun hunting the bands:)
That PAR magic box likes the 100' wire just fine. It did ok with the 44-footer that came with it but naturally, more is better.


Title: RE: What is the best SW antenna ?
Post by: K0OD on July 23, 2012, 04:08:40 AM
Quote
I run a PAR EF-SWL but with a 100' #12 coated wire that is configured as a horizontal "L" and it is up at 40'. I am about a mile and a half from the ocean here, so as you can imagine, I have a lot of fun hunting the bands:)
That PAR magic box likes the 100' wire just fine. It did ok with the 44-footer that came with it but naturally, more is better.

I think the Beach Boys long ago distilled the only thing that matters:

"If everybody had an ocean...

Across the U.S.A. "

"Everybody's gone Dxin'

DXin U.S.A. "

---------------
I once worked a KH6 on 60 meters who was using a 90 foot wire hanging from a tree 50 feet from the Pacific. He was S-9 plus 10dB in Missouri running the then-legal-limit of 50 watts... about 30 dB louder than any other Hawaiian I've heard on that band. The gauge of his antenna wire or whether it was coated didn't count for beans.


Title: RE: What is the best SW antenna ?
Post by: HFCRUSR on July 23, 2012, 08:33:58 AM
Quote
I run a PAR EF-SWL but with a 100' #12 coated wire that is configured as a horizontal "L" and it is up at 40'. I am about a mile and a half from the ocean here, so as you can imagine, I have a lot of fun hunting the bands:)
That PAR magic box likes the 100' wire just fine. It did ok with the 44-footer that came with it but naturally, more is better.

I think the Beach Boys long ago distilled the only thing that matters:

"If everybody had an ocean...

Across the U.S.A. "

"Everybody's gone Dxin'

DXin U.S.A. "

---------------
I once worked a KH6 on 60 meters who was using a 90 foot wire hanging from a tree 50 feet from the Pacific. He was S-9 plus 10dB in Missouri running the then-legal-limit of 50 watts... about 30 dB louder than any other Hawaiian I've heard on that band. The gauge of his antenna wire or whether it was coated didn't count for beans.

I do realize the coating and gauge do not matter, I was just describing what I run. Was there something wrong with that? My point was mainly that being near the ocean helps my reception of points west and southwest of me.


Title: RE: What is the best SW antenna ?
Post by: K0OD on July 24, 2012, 06:32:18 AM
Quote
"I do realize the coating and gauge do not matter, I was just describing what I run. Was there something wrong with that?"

I figured you knew that. 98% of us here know that. But some won't. Every time I stop in the CB shop in the truck stop outside of town I'm reminded tho that utter BS sells antennas.  Love those oil filled, "truck spec'd" antennas they sell tons of!


Title: RE: What is the best SW antenna ?
Post by: HFCRUSR on July 24, 2012, 07:58:59 AM
ah I need to apologize then-I misread your text-I thought I was being B-slapped lol


Title: RE: What is the best SW antenna ?
Post by: K0OD on July 24, 2012, 01:55:23 PM
"The Truck Spec antenna’s oil submersed loading coil is 14 turns of enameled copper wire wound over a grooved plastic insulator. The inners are sandwiched between two heavy, chromed metal tapered ends, and fully enclosed in a clear plastic radome that is filled with clear mineral oil. You can move the antenna around and see the small air bubble move around inside so you can quickly tell that there is still oil in it."

Calling the coil enclosure a radome is hilarious! But no doubt effective ad writing given the audience. Those old CB ads never seemed to establish any purpose for that oil.


Title: RE: What is the best SW antenna ?
Post by: HFCRUSR on July 25, 2012, 08:17:35 AM
That is pretty outragious-I didn't know they were still pimpin' out like that.


Title: RE: What is the best SW antenna ?
Post by: G0DOQ on September 03, 2012, 09:29:26 AM
The best antenna for me is my $50 102' G5RV @ 50' strung between 3 trees as a horizontal flat top.  Almost invisible and picks up weak stations very very well.  Had it @ 20' and it didn't work nearly as good for SWL, so what ever antenna you use height is truly the key.
I've used G5RVs for years. the 102ft is the full size and is a good SWL antenna, the half size is OK but not as sensitive at LF. they come with either 450 or 300 ohm matching section, go for the 300 ohm. a commercial one will have a 239 connector, snip it off and solder the coax back to the rig, any length. do not put in a balun. This is how I transmit on mine also, but it needs a tuner then.
make your  own- a dipole T piece, each leg 51ft, 29ft 6in 300 ohm, and any length of coax.


Title: RE: What is the best SW antenna ?
Post by: KB5UBI on September 03, 2012, 03:09:52 PM
Shielded receiving loops don't tune out noise because of their bandwidth. Most man-made noise is electrostatic and a shielded loop blocks electrostatic signals but allows electromagnetic signals to get through. 


Title: RE: What is the best SW antenna ?
Post by: W0BTU on September 03, 2012, 03:20:50 PM
Shielded receiving loops don't tune out noise because of their bandwidth.

Precisely. They reject unwanted signals or noise because of their directional pattern. They have a deep null at very low angles at right angles to the plane of the loop; and we can point that null at a local source of interference and reduce it. At higher angles, the null is not as deep.

Quote
Most man-made noise is electrostatic and a shielded loop blocks electrostatic signals but allows electromagnetic signals to get through.

Well, that's another story (that I don't have time to go into). But basically, a small loop is only "magnetic" within a very short distance from the antenna.
See:
http://www.w8ji.com/magnetic_receiving_loops.htm
http://www.w8ji.com/radiation_and_fields.htm
http://www.w8ji.com/receiving.htm


Title: RE: What is the best SW antenna ?
Post by: KB5UBI on September 03, 2012, 03:35:07 PM
Notice that I used the term "shielded".


Title: RE: What is the best SW antenna ?
Post by: W0BTU on September 03, 2012, 04:04:23 PM
Notice that I used the term "shielded".

Yes, I noticed that. :-)

Please notice that W8JI states (at the first link) that "Folklore claims a small 'shielded' loop antenna behaves like an electrical sieve of sorts, sorting 'good magnetic signals' from 'bad electrical noise'. Nothing is further from the truth! At relatively small distances a small magnetic loop is more sensitive to electric fields than a small electric field probe."

Believe me, Tom knows exactly what he's talking about! I built such shielded loops from 1/2" hardline  some years ago.

Respectfully,
Mike


Title: RE: What is the best SW antenna ?
Post by: KB5UBI on September 03, 2012, 04:31:07 PM
I too, respect W8JI's opinions. Tom has vast knowledge and practical experience in the field. Don't take everything he, I or others say out of context.

I was first exposed to Shielded Loops in the late 60's when working on an Electronic Counter Measures project and developed my opinion then, but we can agree to disagree. It's an opinion, a theory and nothing more. My opinion: An unsheilded loop will pick up electromagetic (radio waves) and electrostatically induced noise (most man made noise). Most man made noise, has little chance being transformed into true EM radiation. A shielded loop, is mostly insensitive to electrostatically induced noise and when balanced, also has very sharp nulls giving us two chances to rid ourselves of locally generated noise. 

KB5UBI


Title: RE: What is the best SW antenna ?
Post by: W0BTU on September 03, 2012, 04:34:47 PM
Maybe I am taking some of this out of context. I guess it depends on how close the RFI source is. :-)

Exactly what do you mean by "electrostatically induced noise"? A corona discharge is all I can think of that fits that description.