Topics

Loop antennas


Steve & Judy Levine <sandjlevine@...>
 

Loop antennas; Amongst the loop antenna manufacturers, what does the group prefer: chameleons, either F or P, or any of the alpha loops?

I have no interest in dipoles, end not off center fed, anything or whips only loops preferably from 3 to 30. Not interested in something that bottoms out at 7 MHz, and would prefer something that could at least hit 50 if not100 W output SSB. Speak to you fine folks.


Andy_501 <andrew.webb.501.ve4per@...>
 

http://www.66pacific.com/calculators/small-transmitting-loop-antenna-calculator.aspx


I did one for 20 M using 3/4' surplus heliax (16.5 ft circumference)stripped the vinyl outer covering off to make physically light

On 2020-03-24 10:44, Steve & Judy Levine wrote:
Loop antennas; Amongst the loop antenna manufacturers, what does the group prefer: chameleons, either F or P, or any of the alpha loops?

I have no interest in dipoles, end not off center fed, anything or whips only loops preferably from 3 to 30. Not interested in something that bottoms out at 7 MHz, and would prefer something that could at least hit 50 if not100 W output SSB. Speak to you fine folks.


Vic WA4THR
 

I have one of these portable loops that covers 3-17mHz and up to 25w. That is plenty of frequency coverage at this point in the solar cycle and the power of a uBitX.
http://doxytronics.com/

=Vic=


Steve & Judy Levine <sandjlevine@...>
 

Hi Vic, thanks for the link. That looks like PVC that is used for speaders is that correct?  How is the sensitivity on the low end? How about the capacitor is it fairly linear or is it really twitchy? Thanks again for sending me the link I will have to investigate it further.

73’s, Steve KC1ASO


Steve


On Mar 25, 2020, at 05:48, Vic WA4THR via Groups.Io <vhklein@...> wrote:

I have one of these portable loops that covers 3-17mHz and up to 25w. That is plenty of frequency coverage at this point in the solar cycle and the power of a uBitX.
http://doxytronics.com/

=Vic=


iz oos
 

I have just a really nice 2m loop made by a ham, so my experience is very limited. For this reason if I were to choose, I would try a design from a company I trust, which is called ParElectronics.


Il 24/mar/2020 16:44, "Steve & Judy Levine" <sandjlevine@...> ha scritto:
Loop antennas; Amongst the loop antenna manufacturers, what does the group prefer: chameleons, either F or P, or any of the alpha loops?

I have no interest in dipoles, end not off center fed, anything or whips only loops preferably from 3 to 30. Not interested in something that bottoms out at 7 MHz, and would prefer something that could at least hit 50 if not100 W output SSB. Speak to you fine folks.


Dennis Beverage
 

OR, explore building one by scanning for loop antenna projects at ARRL.com.  They have published articles on a couple of very good ones over the past year or so.
--
Sodypop🤠


Laurence Oberman
 

Dennis,
That is an awesome last name to have when you give Antenna advice.
Makes me smile every time I see it.

For those who dont know
https://en.wikipedia.org/wiki/Beverage_antenna

On Wed, Mar 25, 2020 at 3:33 PM Dennis Beverage <Sodypop@...> wrote:

OR, explore building one by scanning for loop antenna projects at ARRL.com. They have published articles on a couple of very good ones over the past year or so.
--
Sodypop🤠


Steve & Judy Levine <sandjlevine@...>
 

Thanks but as I said, I’m going to be undergoing & then recovering from chemo and radiation therapy. I don’t want to build anything else, I just want to play. But thanks a bunch for your suggestions. Perhaps somebody who’s looking for an experiment Will read my post and make good use of your ideas.

73’s, Steve, KC1ASO
Steve

On Mar 25, 2020, at 15:56, Laurence Oberman <oberman.l@...> wrote:

Dennis,
That is an awesome last name to have when you give Antenna advice.
Makes me smile every time I see it.

For those who dont know
https://en.wikipedia.org/wiki/Beverage_antenna

On Wed, Mar 25, 2020 at 3:33 PM Dennis Beverage <Sodypop@...> wrote:

OR, explore building one by scanning for loop antenna projects at ARRL.com. They have published articles on a couple of very good ones over the past year or so.
--
Sodypop🤠


Bob Benedict, KD8CGH
 

You could try posting your question to the loop antennas group

loopantennas@groups.io
    Bob   KD8CGH


Alex Netherton
 

I will reply to this, but I may not be liked for it.
The antenna that is used as a reference for most other antennas is the half wave dipole. It just works. Anything else is generally a compromise. Some antennas like a center fed doublet, fed with twinlead work fine on all bands, but you still have some tradeoffs. 

The problem with loops is that they are often  a fraction of a wavelength on the lower bands,, so when you try to transmit on 40, your losses are horrible.

It is not that hard to do a portable end fed antenna,  just wind it up and slip it in the pack, and carry it up the mountain. Deployment is a cinch if there are any trees around, and if not, a couple of tent poles will do.
Loops are nice, but at the price, I cannot justify shelling out for something that is not as efficient as a dipole, and actually has to be setup when I get there too.
Just sayin'...
--
Alex Netherton, W5ALX
Buncombe County NC, EM85ro


Andy_501 <andrew.webb.501.ve4per@...>
 

with all cost cutting that is in fashion in recent times and a lot of RFI to have to fight to find and fight harder to get it fixed sometimes loop is only way left to cut down a lot of interference. It is why I built a 20 M loop  just give this remote sdr a listen to hear real RFI   http://ve4per.proxy.kiwisdr.com:8073/

Gud DX 73  stay safe

Andy


On 2020-03-25 9:24 p.m., Alex Netherton wrote:
I will reply to this, but I may not be liked for it.
The antenna that is used as a reference for most other antennas is the half wave dipole. It just works. Anything else is generally a compromise. Some antennas like a center fed doublet, fed with twinlead work fine on all bands, but you still have some tradeoffs. 

The problem with loops is that they are often  a fraction of a wavelength on the lower bands,, so when you try to transmit on 40, your losses are horrible.

It is not that hard to do a portable end fed antenna,  just wind it up and slip it in the pack, and carry it up the mountain. Deployment is a cinch if there are any trees around, and if not, a couple of tent poles will do.
Loops are nice, but at the price, I cannot justify shelling out for something that is not as efficient as a dipole, and actually has to be setup when I get there too.
Just sayin'...
--
Alex Netherton, W5ALX
Buncombe County NC, EM85ro


Vic WA4THR
 

Steve, the loop works pretty well, but it is a loop so the "capture area" is a lot less than a dipole and the signals are lower. Tuning is actually pretty easy at lower frequencies and just tuning by peaking the noise in the receiver it will be pretty much dead on with under 1.5:1 SWR. At higher frequencies body capacitance seems to affect it and it gets a little more touchy, but you learn to peak the noise, check SWR, then make a small adjustment in the opposite direction and you are pretty much on. I made the mod to be able to check SWR on screen on my V4 with the CEC software and that makes for a very compact portable package. The rig, the antenna with the PVC arms broken down, a small tripod, and a small 12v Lithium battery all fit in a small cloth briefcase. I made a couple of small WSPR beacon transmission indoors on a table at the Virginia FrostFest in February to demonstrate it and had signals reported back from the west coast. You can see the setup here: http://www.ecars7255.com/Ham%20Projects/WA4THR/Loop%20Antenna%20at%20FrostFest.pdf

=Vic=


McRuss
 

Vic, I took a look at your setup, nice.  The case you are using is the same I have on order for my V6.  Any issues with it and did you use the 3D face-plate or cut your own out?  I intend to try cutting my own but will fall back on the 'ready made' if all else fails.  Glad your loop works well, the commercial model I tried must have been defective because I could never get the SWRs out of the red!
--
Russ
K5FJR


Jack, W8TEE
 

This is our draft of a Double-Double Mag Loop, which was just published in Rad Com. Note how it results in much higher efficiencies.

Jack, W8TEE

On Thursday, March 26, 2020, 10:36:23 AM EDT, McRuss via Groups.Io <wtrrtw@...> wrote:


Vic, I took a look at your setup, nice.  The case you are using is the same I have on order for my V6.  Any issues with it and did you use the 3D face-plate or cut your own out?  I intend to try cutting my own but will fall back on the 'ready made' if all else fails.  Glad your loop works well, the commercial model I tried must have been defective because I could never get the SWRs out of the red!
--
Russ
K5FJR

--
Jack, W8TEE


Dennis Beverage
 

Yah, I'd like to tell you my forfathers  invented the Beverage antenna.  I've investigated that but turned up little info on it's origination.  I did have one when I was a kid building my own one tube receivers so I could lay awake at night listening to baseball games in far away places.  I was a farm boy with lots of acreage and that antenna was probably 80 yards or so long.  It was a simple antenna for a kid requiring no poles, hangars or much else.  I just laid it on the ground along a fence line.
--
Sodypop🤠


Murray Wills (ZL2IQ)
 

Fantastic article Jack.

Thank you for sharing it.

 

73 Murray ZL2IQ

 

Rev Murray Wills

Box 31-227

Lower Hutt 5009, New Zealand

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Jack, W8TEE via Groups.Io
Sent: Friday, 27 March 2020 3:51 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Loop antennas

 

This is our draft of a Double-Double Mag Loop, which was just published in Rad Com. Note how it results in much higher efficiencies.

 

Jack, W8TEE

 

On Thursday, March 26, 2020, 10:36:23 AM EDT, McRuss via Groups.Io <wtrrtw@...> wrote:

 

 

Vic, I took a look at your setup, nice.  The case you are using is the same I have on order for my V6.  Any issues with it and did you use the 3D face-plate or cut your own out?  I intend to try cutting my own but will fall back on the 'ready made' if all else fails.  Glad your loop works well, the commercial model I tried must have been defective because I could never get the SWRs out of the red!
--
Russ
K5FJR


--
Jack, W8TEE


_Dave_ AD0B
 

The best antenna  that I have used are antennas that are large loops. The signal strength is comparable to a dipole but the noise floor is lowered 10db approximately. Our previous loop was 1300' and seemed to have the best signal both on transmit and receive.

Our current loop is 2600' It performs excellent on 160 and 80m but rolls off above that. Most signals sound like they are vhf FM. 
--
73
Dave
ADOB
Raduino bracket and Ham_Made_Keys


Vic WA4THR
 

Thanks, Russ. As I mentioned, mine is a V4 uBitX built over a year ago and no case or template was offered at that time. However, the Banggood case is easy to work with and I had used it on a BitX40 a year before. I just used a drill for the round openings and a small dremel and file for the big. A suggestion, since most of the panel gets cut away with the big opening, the strength is much less and you might break it when drilling the other holes, so cut them first. Ask me how I know...  That said, since the front and back are basically just flat pieces you can substitute another panel out of plastic or metal if needed. These rigs have been popular and are frequently heard checking in to the ECARS net which runs every morning on 7.255 mHz from 0730-1300 or later. You can see a few of the other builds described on their website in this section: http://www.ecars7255.com/Ham%20Projects/Ham_Projects.htm

=Vic=


McRuss
 

Vic,
The V6 kit without case comes with 'templates' for front and back that are fairly thick, looks a little like plexiglass with an opaque covering.  Too thick to use as the volume/on-off switch won't protrude far enough to get the nut or the knob on but good for drilling and cutting the case parts.  I'll check the ECARS net.  Thanks!
--
PS, glad I got my V6 just before India shut down!!

Russ
K5FJR