Rate / Critique My Antenna Setup Please

[prcguy]

I think the OP would benefit most from a 9:1 transformer outside and run 50 ohm RG-58 type coax to the radio via an 1/8" plug. You don't want to just connect a bunch of wire to coax and bring it in as the impedance will be swinging from one extreme to the other over the SWL bands causing extra loss and a 9:1 transformer will tame that some and be presentable to 50 ohm coax.

If your going to ground anything you would want to to that outside and as close as possible to the main AC power entry point of the house using the shortest run of 10 ga wire. That is code for in USA and I am not familiar with the electrical codes in Canada.

 

[K4EET]

@MikeThompson, take a look at this webpage for a good understanding of the components of a dipole antenna system. Again, since you will not be transmitting, all of these components will not be required. Actually, most of them are not needed. But it is a good idea to go ahead and learn about them so that you will know the different components.

Dipole Antennas - Palomar Engineers®

Dipole antennas are very simple to construct and use and are very efficient if matched correctly at the feed point height. Dipole antennas and coax feed line can pickup neighborhood noise which can mask many weak signals and hinder reception and two-way communication. Fortunately Palomar...

palomar-engineers.com

Let me/us know if you have any questions...

73, Dave K4EET

 

[K4EET]

@prcguy, what do you think about the antenna for Mike? Should he be looking at a dipole or an end-fed or some other kind of antenna for his shortwave listening? We might also want to pick out the most probable/best SWL band(s) and see what antenna lengths make sense as well. Thoughts?

 

[K4EET]

@MikeThompson, here is a good article on End-Fed Antennas:

End Fed Antennas - Palomar Engineers®

Stealthy end fed antenna for portable, emergency, permanent locations - 1.8-61 MHz, 500-5000 Watts PEP. Quick setup, no radials, low SWR, neighbor friendly.

palomar-engineers.com

73, Dave K4EET

 

[prcguy]

The PAR SW End Fed up in the clear is a great all around SWL antenna and I would recommend something like that. Its also best to keep the hot antenna wire away from the house whenever possible to minimize RFI pickup from things inside the house. Sometimes RFI can travel on ground conductors so you also have to be careful when grounding an antenna like this and check for a noise increase when attaching any ground.

I suppose the OP could just get a 9:1 transformer like the PAR has and use the existing wire wrapped around the house with some new coax feeding the receiver, but I think it will work much better with the wire stretched out in the clear heading away from the house.

I big dipole can also work well but not a resonant center fed with direct coax feed as the impedance swings will be severe over the SWL bands and some sort of medium impedance matching transformer would be needed at the center or offset to smooth that out. Plus the feedline would hang down from the center possibly causing a problem bringing it back to the house. This is why I like end feds unless you want to make the dipole the crowning jewel of your roof so the coax drops down easily into the radio room.

@prcguy, what do you think about the antenna for Mike? Should he be looking at a dipole or an end-fed or some other kind of antenna for his shortwave listening? We might also want to pick out the most probable/best SWL band(s) and see what antenna lengths make sense as well. Thoughts?

 

[popnokick]

The PAR EF-SWL is exactly what RR member scloyd is using. He has an entire thread here on RR describing his installation (with photos) and his experience found here My First SW Radio and Antenna. A Couple of Questions. (Photos)
scloyd also has replied a couple of times to Mike Thompson in this thread. The scloyd PAR EF-SWL installation is in circumstances very similar to Mike Thompson's.

 

[scloyd]

The PAR EF-SWL is exactly what RR member scloyd is using. He has an entire thread here on RR describing his installation (with photos) and his experience found here My First SW Radio and Antenna. A Couple of Questions. (Photos)
scloyd also has replied a couple of times to Mike Thompson in this thread. The scloyd PAR EF-SWL installation is in circumstances very similar to Mike Thompson's.

Mike Thompson and I are friends from another forum (not radio related) and we have been emailing back and forth about our set-ups. I believe Mike wants to run it up into his attic as a end fed antenna either stretching acoss the length of the attic or around the entire perimeter of the attic (inside). I also believe Mike wants to eliminate the antenna outside altogether.

Am I correct Mike?

I am done with my new 85' PAR EF-SWL and will be updating my thread soon.

 

[K4EET]

<snip>
I am done with my new 85' PAR EF-SWL and will be updating my thread soon.

Reason? Please either post here or link your response here from your other thread. Thanks! Dave

 

[MikeThompson]

Thanks for all the great responses and feedback guys!

take a look at this webpage for a good understanding of the components of a dipole antenna system.

I think I ran into that site before in my search. He's a dipole I think is what I'm looking for. Thanks Dave! As I would be running this dipole system inside, what would everyone suggest to reduce noise? I think using the coax will make a huge difference, but for in the attic?

to keep the hot antenna wire away from the house whenever possible to minimize RFI pickup from things inside the house.

The scloyd PA

I believe Mike wants to run it up into his attic as a end fed antenna either stretching acoss the length of the attic or around the entire perimeter of the attic (inside). I also believe Mike wants to eliminate the antenna outside altogether.

Am I correct Mike?

Yes Scott, I want to keep it entirely contained within the house, with the antenna being up in the attic.

I am done with my new 85' PAR EF-SWL and will be updating my thread soon.

do you mean done as in finished, or done as in you are frustrated and throwing it in the garbage?

 

[scloyd]

do you mean done as in finished, or done as in you are frustrated and throwing it in the garbage?

As in finished. I have been frustrated a few times, but not enough to trash it all.

 

[TailGator911]

I use a multitude of SWL antennas with my HF radios. I have a PAR end-fed 60-footer that runs from my mast to a tree in my backyard. I also have a random wire kit I built that runs in a different direction 80-ft. My favorite is my W6LVP magnetic loop, which I have perched on a heavy duty loudspeaker tripod just outside my radio room with maybe 15-ft coax run. My fav combo right now is the loop and my Icom R8600. On a clear night I can hear forever

 

[popnokick]

I think I ran into that site before in my search. He's a dipole I think is what I'm looking for. Thanks Dave! As I would be running this dipole system inside, what would everyone suggest to reduce noise?

There are major differences between a dipole and an end-fed halfwave antenna.... the biggest being that the end-fed is going to perform well for receiving across a much broader range of shortwave frequencies than the dipole. It is much more likely that what will work best over the widest range of frequencies in your attic is the end-fed antenna.... not a dipole.

 

[MikeThompson]

An end fed antenna I thought needs to be strung out from a high point on to a further point like on a tree. Can this be achieved in an attic? The angle wouldn't be that much compared to having it outside.

 

[vagrant]

As you may know, things in your home produce "noise". Positioning the antenna further from the interference is obviously helpful. Keeping your antenna in the attic keeps it close to the noise. If it must be in the attic, then so be it.

Years ago I had a setup similar to yours, or what you are working to achieve. I used inexpensive RG58 50 ohm coax cable from my radio to a 9:1 balun which was connected to the antenna, which was just a random length of wire. This is basically what prcguy noted previously. The wire was under the eve of my roof line to keep it out of sight. While it did improve my reception over the built-in antenna on the radio, the wire also worked well to pick up noise. Still, the wire improved the signal enough to overcome the noise to some degree. When compromising, we take what we get.

A. The wire/antenna picks up whatever radio wave/signal hits it.
B. The 9:1 balun works to take an Unbalanced line/wire and make it Balanced (Balun) then feeding the 50 Ohm coax.
C. The shielded coax then takes the energy/signal that hits the wire and carries it to your radio. The shield of the coax works to reduce/stop noise in your home from getting into the signal received from the antenna. Still, if your antenna is near or in the noise your receive will suffer. Thus, the push for outdoors away from the home.

Here's a test you can easily do with what you have. Take a radio that receives AM and dial it off frequency so that all you hear is noise and not a station signal. Now walk around the inside and outside of your home. Then walk three, five and 10 meters from your home while listening. My guess is that you will hear the noise reduce and appreciate that the further away your antenna is from the home, the better for receiving it will be. Experiment and have fun!

With all of the above in mind some of us, perhaps many, enjoy using a loop antenna over a wire for RX. A loop has an advantage of being rotatable to null out noise. Even with the loop one meter off of the ground, it works very well and raising it up higher does not necessarily result in improved performance. Some use a rotor and some set it where the noise is reduced and leave it alone. With a loop, you would run just the coax to it. Some loops are active and use power to amplify the signal, others are passive and take what they get.

 

[popnokick]

An end fed antenna I thought needs to be strung out from a high point on to a further point like on a tree. Can this be achieved in an attic? The angle wouldn't be that much compared to having it outside.

Ideally, yes in a perfect installation you would string the end fed antenna OUTDOORS in as straight a line... and as high up... as possible. But you state you will be in the attic with the wire. The end fed wire is going to be much more tolerant of the bends / angles you may have to make to squeeze it into the attic than the dipole would be... and you will still get the broader frequency range of the end fed antenna and balun. What you are shooting for in your attic with a wire antenna is to put it as high as possible, away from large metal objects and other wiring, and as few bends as possible... certainly not "folding it back upon itself" at all.

 

[ka3jjz]

How big is the attic? I've seen many reports of folks using the MLA-30 loop with portables with good results. As stated before, loops are resistant to noise - something you will be fighting keeping the antenna indoors. It's quite inexpensive - the new plus model is, I believe USD50 or so on eBay. If your attic has some size to it, putting the loop on a very inexpensive TV rotor on a tripod would make a commendable antenna even if it is a compromise - and make no mistake, indoor antennas are ALWAYS a compromise.

The link to it and it's older brother - with some background - can be found in our loops wiki, viz.

Loops - The RadioReference Wiki

wiki.radioreference.com

Mike

 

[popnokick]

Certainly can't beat the price for ka3jjz's suggestion of the MLA-30 mag loop! And as he notes, loops will pick up much less noise than long wires. You may need to rotate a loop to peak up reception from a given station, but you certainly can point it in the direction where it receives the most and leave it alone. If you have room in the attic... put up both antennas, run coax to both of them, and connect them to an A - B two position coax switch. Then you can select whichever one receives best

 

[MikeThompson]

If you have room in the attic... put up both antennas, run coax to both of them, and connect them to an A - B two position coax switch. Then you can select whichever one receives best

I like that idea! There is no power outlet up there to power an active loop, but there is room for a loop I think.

 

[MikeThompson]

Maybe slightly off topic, but what drawbacks if any, are there of mounting a passive loop next to a tv digital antenna?

 

[krokus]

Maybe slightly off topic, but what drawbacks if any, are there of mounting a passive loop next to a tv digital antenna?

There is no digital antenna, just antennas.

That said, the possible drawbacks are minimal, unless there are signals "leaking" from the TV, onto the coaxial cable.