Getting back into HF (maybe)

[jazzboypro]

Hello all,

I am thinking of getting back into HF. I have not bought the radio yet but if i do it will probably be an Icom. I'm trying to figure out my options for an antenna. I have trees in my backyard but they hare very close and even touching the power lines so i don't want to use those trees as support for an antenna. An horizontal antenna would be difficult to put in place du to the lack of tall support. I had a vertical in the past that was installed in a tree but that tree is no longer there. I think a loop antenna would be my best option i'm thinking of a Wellbrook loop antenna. I know that the higher the better when it comes to antennas but what would be the minimum height for a loop to work reasonably well on let's say 20 meter ?

Thanks
73
VA2FCS

 

[ka3jjz]

Since you're talking about a Wellbrook I'm going to assume here - since you posted in the amateur radio forum - that you aren't going to be transmitting, as a Wellbrook is not designed for that. But there are loops that are.

Height is not as much a concern with loops. In fact if you are listening below 2 or 3 Mhz, you want it reasonably close to the ground (most references I see say about 10 foot or less). This is to take advantage of the ability to null out one signal for another. Any higher and you might lose that ability or have it seriously compromised. This is because a loop would become more sensitive to skywave propagation and make nulling more difficult. I've even see loops hidden in a garden to avoid the gaze of condo nazis.

Just to bring this back to OT for the forum, there are a great many other loops besides the Wellbrook, and numerous ones that can be used for transmitting. You can find a huge number of links here...

Loops - The RadioReference Wiki

wiki.radioreference.com

Mike

 

[vagrant]

1. Call the power company and have them cut the trees back from the power lines. Perhaps call today, even if you don't run a wire to the trees.

2. A Wellbrook loop antenna is for RX only. Unless there's something new that they make for TX I am unaware of. There might be.

3. A reasonably inexpensive way to get back into HF is an Off Center Fed, or End Fed antenna. You can run the OCF as an inverted V and get the apex up about 30'-36' (9-11 meters) and you can run 40-6 meters. I use trees for one Off Center Fed running horizontal and a 40' ROHN push up mast for the other OCF as an inverted V. ( I use a non-conductive extension at the top to get the wire away from the mast. ) I also use the mast to hold an End Fed from time to time as well. You can easily build either one of these, or purchase something for low cost. ( Important Point: I use an RF choke at the antenna feed point for the OCF antennas. If you go with an End Fed, somewhere near the radio end is best. Some OCF users place a choke at both ends to reduce noise/RFI. )

4. If you want a loop, I use a Chameleon F-Loop. Low to the ground is better. Actually, putting the loop up high does not help. Unfortunately, a loop like that is not efficient. An End Fed, or Off Center fed antenna will beat it all day long and you don't have to keep tuning the wire antennas. You would need to tune the loop constantly.

5. Coax is another critical part of the overall system. I use LMR-400 for HF. Some would say that's a bit much, but one of my runs is 130'. With HF we can get away with less, but I found out that I am not going to live forever even if I wash my hands and sleep eight hours a day..and my relatives don't need my money.

6. I have a vertical for 10 and 15 meters, but I get plenty of RFI with it being a vertical. A favorite for 20 - 6 meters is a hexbeam, which is not a vertical. I use the one made by K4KIO, but there are others.

 

[TiredCat]

There are many options available to you. If you can get a copy of the ARRL antenna handbook, there is an amazing amount of options for HF antennas in endless configurations. You have to first figure out what it is you are wanting to accomplish...ie what bands would you really like to work. Then you have to choose what best fits you real estate. I have an end fed that covers 80 - 10 meters that actually does a descent job on every band but 80 meters. It is usable there, but very inefficient and requires the use of my antenna tuner. But it does reasonably well on the other HF bands. It is a trade-off......it does nothing extremely well, but does a lot somewhat well. I also have a home-brew parallel (fan) dipole that is horizontally stretched across my yard with a 40 ft mast pole in the center. One dipole is cut (tuned) for 40 meters and the other for 20. No antenna match needed there. Both are resonant for their respective bands and it works wonderful. Actually surprisingly well. You just have to really survey your property and think through what antenna would work best with what you have available and what bands you think you would want to work the most. Good luck with it and have fun! Building your own antenna is probably one of the most rewarding aspects of ham radio... to me any way.

 

[jazzboypro]

Since you're talking about a Wellbrook I'm going to assume here - since you posted in the amateur radio forum - that you aren't going to be transmitting, as a Wellbrook is not designed for that. But there are loops that are.

Height is not as much a concern with loops. In fact if you are listening below 2 or 3 Mhz, you want it reasonably close to the ground (most references I see say about 10 foot or less). This is to take advantage of the ability to null out one signal for another. Any higher and you might lose that ability or have it seriously compromised. This is because a loop would become more sensitive to skywave propagation and make nulling more difficult. I've even see loops hidden in a garden to avoid the gaze of condo nazis.

Just to bring this back to OT for the forum, there are a great many other loops besides the Wellbrook, and numerous ones that can be used for transmitting. You can find a huge number of links here...

Loops - The RadioReference Wiki

wiki.radioreference.com

Mike

I must have not pais attention whilw i was on the wellbrook site, i do intend to transmit with a loop. Thanks for the link.

1. Call the power company and have them cut the trees back from the power lines. Perhaps call today, even if you don't run a wire to the trees.

2. A Wellbrook loop antenna is for RX only. Unless there's something new that they make for TX I am unaware of. There might be.

3. A reasonably inexpensive way to get back into HF is an Off Center Fed, or End Fed antenna. You can run the OCF as an inverted V and get the apex up about 30'-36' (9-11 meters) and you can run 40-6 meters. I use trees for one Off Center Fed running horizontal and a 40' ROHN push up mast for the other OCF as an inverted V. ( I use a non-conductive extension at the top to get the wire away from the mast. ) I also use the mast to hold an End Fed from time to time as well. You can easily build either one of these, or purchase something for low cost. ( Important Point: I use an RF choke at the antenna feed point for the OCF antennas. If you go with an End Fed, somewhere near the radio end is best. Some OCF users place a choke at both ends to reduce noise/RFI. )

4. If you want a loop, I use a Chameleon F-Loop. Low to the ground is better. Actually, putting the loop up high does not help. Unfortunately, a loop like that is not efficient. An End Fed, or Off Center fed antenna will beat it all day long and you don't have to keep tuning the wire antennas. You would need to tune the loop constantly.

5. Coax is another critical part of the overall system. I use LMR-400 for HF. Some would say that's a bit much, but one of my runs is 130'. With HF we can get away with less, but I found out that I am not going to live forever even if I wash my hands and sleep eight hours a day..and my relatives don't need my money.

6. I have a vertical for 10 and 15 meters, but I get plenty of RFI with it being a vertical. A favorite for 20 - 6 meters is a hexbeam, which is not a vertical. I use the one made by K4KIO, but there are others.

I will probably die before the power company comes to cut the trees . It looks like i did not pay attention when i was checking out the wellbrook loop. I do intend to transmit. Thanks for the antenna suggestions. I plan on using LMR400 that's was i use for my 2M/70 CM installation.

There are many options available to you. If you can get a copy of the ARRL antenna handbook, there is an amazing amount of options for HF antennas in endless configurations. You have to first figure out what it is you are wanting to accomplish...ie what bands would you really like to work. Then you have to choose what best fits you real estate. I have an end fed that covers 80 - 10 meters that actually does a descent job on every band but 80 meters. It is usable there, but very inefficient and requires the use of my antenna tuner. But it does reasonably well on the other HF bands. It is a trade-off......it does nothing extremely well, but does a lot somewhat well. I also have a home-brew parallel (fan) dipole that is horizontally stretched across my yard with a 40 ft mast pole in the center. One dipole is cut (tuned) for 40 meters and the other for 20. No antenna match needed there. Both are resonant for their respective bands and it works wonderful. Actually surprisingly well. You just have to really survey your property and think through what antenna would work best with what you have available and what bands you think you would want to work the most. Good luck with it and have fun! Building your own antenna is probably one of the most rewarding aspects of ham radio... to me any way.

I have a copy of the book and i will look at it. Thanks for the suggestions

 

[W0JOG]

As you develop an antenna plan, a vertical is better than nothing. I have a Cushcraft from DX Engineering that has gotten me back on the air from the assisted living home where I wound up as an old person alone. The vertical is a bunch of compromises, but it will get you on the air and maintain schedules as well as get you back with the ones you have talked to when antenna options were better. I had 10 acres for many years with wire doublets for 40 and 80 and a rotatable dipole at 30 feet for the higher HF. I miss it very much. But, as I write, "something (vertical) is better than nothing!"

73 de W0JOG

 

[WB9YBM]

I have trees in my backyard but they hare very close and even touching the power lines so i don't want to use those trees as support for an antenna.

I would discourage tree use either way since I heard a few years ago about one op running legal limit setting his tree on fire (either that or make sure the insulator/guy rope extends from the tree far enough out that the actual antenna radiator is well away from leaves, branches, etc.). (He didn't even know it was happening until he heard sirens stop in front of his house...)

 

[jazzboypro]

I would discourage tree use either way since I heard a few years ago about one op running legal limit setting his tree on fire (either that or make sure the insulator/guy rope extends from the tree far enough out that the actual antenna radiator is well away from leaves, branches, etc.). (He didn't even know it was happening until he heard sirens stop in front of his house...)

It was not my intention of using those trees. I would really like to experiment with a loop. I'll se what i'll do.

 

[jwt873]

As others have mentioned, a Welllbrook won't be of much use. They are receiving loops and won't work for transmitting.

You want to look at loops designed for transmitting. Here's a pretty good write up on construction etc. --> KK5JY Small Transmitting Loop Project

If you search for magnetic loops, there's quite a bit more. They even make commercial ones. For example --> MFJ-1788, SUPER HI Q LOOP, 36~DIA, 15-40 METER

 

[ka3jjz]

And there are others in the wiki article for which the link was given earlier....Mike

 

[jazzboypro]

As others have mentioned, a Welllbrook won't be of much use. They are receiving loops and won't work for transmitting.

You want to look at loops designed for transmitting. Here's a pretty good write up on construction etc. --> KK5JY Small Transmitting Loop Project

If you search for magnetic loops, there's quite a bit more. They even make commercial ones. For example --> MFJ-1788, SUPER HI Q LOOP, 36~DIA, 15-40 METER

I would like something commercially available. I've had MFJ stuff in the past, let's say i would prefer another brand...

And there are others in the wiki article for which the link was given earlier....Mike

I'm starting to look at it, very interesting

 

[SA4MDN]

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