Horizontal room loop . . . add another loop?

[KB2GOM]

I have already posted here about my desire to improve HF reception without resorting to an outside antenna, and I came up with this:

Jock designs a Horizontal Room Loop to cope with reception issues

Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post: Got reception issues? An idea worth considering: the “Horizontal Room Loop.” by Jock Elliott (KB2GOM) When…

swling.com

The results are markedly better than the whip antenna on my Satellit 800, but then the thought occurs: what would happen if I added another loop of wire around the room? Not in parallel, but in series, so that the total length of the antenna would be about 100 feet?

Do you think it would improve reception? Make it worse? No difference?

Inquiring minds want to know.

And before you tell me that what I really need to do is to put up an antenna outside where it can get some fresh air, I know that. Been there, done that, and I agree. But my shack being where it is, I have a serious problem with nearby power lines that, if Mr. Murphy comes to visit, could fall on an outside wire antenna and cause no end of havoc.

So humor a weird old guy with a radio and tell me if adding another loop to the horizontal room loop would do any good or not.

 

[ka3jjz]

I seriously doubt it.

If you bought a loop and put it outside, you wouldn't want to mount it high up, as you would with a wire antenna. 10-15 foot maximum; typically folks will keep it only a few feet off the ground.

No worries about Murphy causing the antenna to call on power lines

Mike

 

[KB2GOM]

I seriously doubt it.

If you bought a loop and put it outside, you wouldn't want to mount it high up, as you would with a wire antenna. 10-15 foot maximum; typically folks will keep it only a few feet off the ground.

No worries about Murphy causing the antenna to call on power lines

Mike

Mike,

Elsewhere on RR, I posted an inquiry about transmitting using small loop antennas, and a couple of people responded that "Tuning was super touchy with a narrow range, making it OK for something like FT8 or ops where you park on a freq, but less than ideal for tuning around. " and " Bandwidth too narrow, made waterfall display about useless. SWR too high. Tuning capacitor too touchy. "

Are the small loops (Wellbrook, etc.) also touchy for receive only? Many people here have said good things about them.

 

[vagrant]

@KB2GOM - The transmit loops are different. The comments myself and others made in that thread, which you noted, are accurate...for those types of antennas. While they can of course receive if you are looking to RX only then go with the Wellbrook, or for less money a W6LVP solution. Search this site for posts by members about the W6LVP and you'll probably find what you need there, in particular search for comments made by prcguy. You can still turn the loop to avoid noise and it will work in the house. Of course the noise from things in your home may cause noise. They only way to find out is to deploy the antenna and find out. You'll probably be happy...if you only need a RX only antenna, as those do not work for transmit. You won't find those antenna types narrow and or require constant tuning. Those antennas also use a pre-amp.

As to your question in the other thread about a wire and it folding back, that will work, but I would just keep running it from the side of your cottage to either the back or front. A thin bit of wire is very easy to hide under an eve. Look for the Par SWL End Fed EF-SWL. Alternatively, you make your own 9:1 transformer and source around 45' of thin wire. There is also a low cost 9:1 transformer ready to go. You may find that an RF choke (1:1 choke) my cut down the noise when using a wire. These are easy to make, or source pre-built as well. I would try the wire first and if everything is okay, not too much static coming in with signals, then the choke may not be needed. If you do deploy one on the coax going to the antenna, place it just outside the house on the coax, or even up to the feed point. This will usually reduce noise from inside the house traveling up the coax and being received on the antenna, then coming back in.

The wire antenna will be the lowest cost solution. Still, I would leave it in place and use a coax switch should you choose to also go with the loop.

* One other thing you and others may need is an AM broadcast filter, due to their proximity nearby and power output. There is an inexpensive one with the RTL-SDR brand name and works well. I also have the RX only AM filter made by Dale Par and it too works very well. Your receiver and or software program may handle the AM broadcast fine, but for $20 it will help and has a low insertion loss for frequencies you do want to hear, presuming you do not want to hear AM broadcast stations 500-1700 kHz. The Par filter has a switch which allows you to take it out of line should you want to listen to AM broadcast stations. Well, mine does, but I purchased it about 10 years ago.

At this point, I am unsure if you want to use a loop to transmit, or only to RX. Let us all know, so we can focus on the solution.

 

[ka3jjz]

In the original post, the OP said that he's using a Satellit 800, so receive only.

Active loops like the Wellbrook, W6LVP, etc. require no touch up tuning. Passive loops like the Chameleon or the DoxyTronics do require tuning. In an urban environment, and if you're using a SDR, these passive loops might help limit any RF garbage that is outside the tuning of the loop.

Mike

 

[wscranston]

Just like this question, there are two answers to every HF antenna question:

1. It depends
2. Try it and see

 

[KB2GOM]

@KB2GOM - The transmit loops are different. The comments myself and others made in that thread, which you noted, are accurate...for those types of antennas. While they can of course receive if you are looking to RX only then go with the Wellbrook, or for less money a W6LVP solution. Search this site for posts by members about the W6LVP and you'll probably find what you need there, in particular search for comments made by prcguy. You can still turn the loop to avoid noise and it will work in the house. Of course the noise from things in your home may cause noise. They only way to find out is to deploy the antenna and find out. You'll probably be happy...if you only need a RX only antenna, as those do not work for transmit. You won't find those antenna types narrow and or require constant tuning. Those antennas also use a pre-amp.

As to your question in the other thread about a wire and it folding back, that will work, but I would just keep running it from the side of your cottage to either the back or front. A thin bit of wire is very easy to hide under an eve. Look for the Par SWL End Fed EF-SWL. Alternatively, you make your own 9:1 transformer and source around 45' of thin wire. There is also a low cost 9:1 transformer ready to go. You may find that an RF choke (1:1 choke) my cut down the noise when using a wire. These are easy to make, or source pre-built as well. I would try the wire first and if everything is okay, not too much static coming in with signals, then the choke may not be needed. If you do deploy one on the coax going to the antenna, place it just outside the house on the coax, or even up to the feed point. This will usually reduce noise from inside the house traveling up the coax and being received on the antenna, then coming back in.

The wire antenna will be the lowest cost solution. Still, I would leave it in place and use a coax switch should you choose to also go with the loop.

* One other thing you and others may need is an AM broadcast filter, due to their proximity nearby and power output. There is an inexpensive one with the RTL-SDR brand name and works well. I also have the RX only AM filter made by Dale Par and it too works very well. Your receiver and or software program may handle the AM broadcast fine, but for $20 it will help and has a low insertion loss for frequencies you do want to hear, presuming you do not want to hear AM broadcast stations 500-1700 kHz. The Par filter has a switch which allows you to take it out of line should you want to listen to AM broadcast stations. Well, mine does, but I purchased it about 10 years ago.

At this point, I am unsure if you want to use a loop to transmit, or only to RX. Let us all know, so we can focus on the solution.

At this point, listening only.