Should I add more "antenna" length for better SWL?

[raisindot]

I know, the antenna forum is generally the place for these, but most of those posts are about scanner antennas. This is about an HF/SWL antenna.

Anyway, I currently have my PAR SWL connected to a tree about 50 feet from my house. The PAR is grounded by a ground rod near the tree, LMR400 coax cable runs underground to my window, where I have it attached to a grounding platform grounded to another ground rod next to the house. More LMR400 cable goes into the house to my JRC 545.

My antenna wire is basic thin shielded copper wire going in a moderate slope about 60 feet to the back of my property line, strung up through trees.

I would say that this configuration delivers pretty well across the spectrum. However, I'd considering lengthening the antenna cable by making a right turn at my property line and running along the back of my property for another 100 feet or so--essentially creating a horizontal "L". It would be neat to consider a loop but my wife would probably divorce me if she saw huge loops in the yard--I'm trying my best to keep her from seeing the main longwire itself by hiding in the tree branches.

My question is: Would doing this be a case of diminishing returns? I guess I'd like to be able to hear more below 5Mhz or improve reception overall. Would having such a longwire running both north/south and east/west help this any?

Jeff

 

[kb2vxa]

From Par:
"The Par Electronics EF-SWL is an end-fed short wave antenna optimally designed for 1-30 MHz reception."

"Would doing this be a case of diminishing returns?"
Most likely.

 

[raisindot]

From Par:
"The Par Electronics EF-SWL is an end-fed short wave antenna optimally designed for 1-30 MHz reception."

"Would doing this be a case of diminishing returns?"
Most likely.

Ummmmm...can you please elaborate? The PAR says nothing about the maximum antenna length you can use with it.

Jeff

 

[Murstech]

If the antenna is 60 feet long right now then I would say making it longer almost has to improve your reception below 5 mhz. What I would be most concerned with is noise pickup. Hopefully the addition of the extra wire doesnt run close to anything that emits noise.

 

[ka3jjz]

The amount of wire you add should not increase noise pickup, assuming that you are not running it near anything that would be an emitter. However it would change the points at which the antenna would be resonant. In addition the longer you get, at least in some cases, the antenna would become somewhat more end-fire, depending on the frequency, height above ground and many other factors. If you're interested in researching this topic, the ARRL Antenna handbook is a great place to start.

I know many folks that use anywhere from 80-100 foot of wire - 80 foot is roughly a quarter wave on 3 mhz, so that's a nice number to use.

Keep in mind that as we get closer to the summer months, TStorm noise and absorption is going to become more and more of a problem. Set up now for better tropical band reception, but understand that, with the exception of a few quiet days, from here until September or October (assuming you are in the East coast of NA) things are going to go downhill in a very short while insofar as the tropical bands is concerned

73 Mike

 

[Alliance01TX]

Longer Wire for SWL

Howdy

With different points of view on this from prior post I would certainly experiment with longer and various directions on the compass......

You might even try some different loops, quads or other wiring schemes to see what add's to or reduces noise or interference if you are close to same, etc...I have run long wires in N-S-E-West headings and found some interesting things at times.

I use the WWV or other International Time Stations to experiment with HF Antenna Array's as the WWV 5-10-15 MHz Time Interval broadcast give at least a reasonable constant to experiment.

The summer season will also have some impacts on the lower freq's you are looking as well...you might want to look a MUF-LUF charts to aid in the times of experiments as the seasons change as well....

Enjoy the challenge....as noted prior, the ARRL Antenna Handbook is indeed a great reference.

Thx

Bill

 

[lanbergld]

Jeff,

I don't know if you're dead set on those outdoor longwire things, but for the lower frequencies (say < 5000 kHz) inductance will give you what you want. Of course when I talk inductance I'm speaking about loop antennas, which is all I use period. The more turns of wire on the loop, and the closer together the turns are, the higher your inductance and the better reception you'll have going down in frequency. And you won't have to run wires clear over to the next town.

From longwave up through 160 meters I use ferrite loopstick antennas. Not much wire or space is needed, and a good ferrite loopstick will pull in signals better than a large wire antenna anyday of the week. (On the low frequencies) Take a look at the "monster rods" that Stormwise sells. They really work.

But anyhow, for lower frequencies think induction. Even on the bottom portion of shortwave.


Larry Lanberg

Richmond VA

 

[ka3jjz]

Here's Stormwise's website - interesting, they also sell variable caps, very useful for making a tuning section for a loop...

903-383-7047 Stormwise Outdoor Lightning Detection

Also see the Shortwave monitor website I posted in another thread. There are several rather unique antenna projects, even one or two for the popular 60 meter band

73 Mike

 

[lanbergld]

Yes those ferrite loopsticks definitely need to be tuned. I use a variable capacitor pulled from a an old Panasonic table radio. I simply connect the 2 ends of my coil to the capacitor with tiny alligator clips. On the other end of the ferrite rod I have a smaller coil (pickup coil) that runs into my receiver. Takes me every where I want to go. I regularly get European longwave broadcast stations, which I couldn't do even on the largest wire loop.

And Litz wire isn't needed either. I use speaker wire.

But yes, those Stormwise monster rods are worth the money. If you want to do well on low and medium frequency.


Larry Lanberg

Richmond VA

 

[k9rzz]

+1 on loops, for all frequencies. I once made a 20 ft per side wire loop strung between two trees with the wire being 4 conductor cable I got a Home Depot. Soldered the wires in series so it was a 4 turn loop, then fed it (un-tuned) with window line. KILLER from 100 khz through 5 mhz.

 

[datainmotion]

Here's Stormwise's website - interesting, they also sell variable caps, very useful for making a tuning section for a loop...

903-383-7047 Stormwise Outdoor Lightning Detection

Also see the Shortwave monitor website I posted in another thread. There are several rather unique antenna projects, even one or two for the popular 60 meter band

73 Mike

Gosh I love the links you post. Seriously!