Beverage or Wellbrook Loop?

Useful information regarding antennas for SDR products.
SanJacinto
Posts: 6
Joined: Sat Dec 31, 2016 9:06 pm

Beverage or Wellbrook Loop?

Postby SanJacinto » Sat Jan 07, 2017 3:07 pm

I've been going back and forth between purchasing a Wellbrook Loop or constructing a 300 meter Beverage antenna. Has anyone out there ever used both setups and been able to determine a performance comparison between the two? Obviously a Wellbrook would have some advantages because it can be rotated. By the time I source the materials needed to erect a single or bi-directional Beverage of that length, I'm at the price of the Wellbrook ALA1530LNP NA.

My main receiving goals are MW from Eastern North America and LW/MW DX from UK/Europe. At my location in Texas, a Beverage at 40-50 degrees Azimuth points me to my objectives.
Last edited by SanJacinto on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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g1hbe
Posts: 216
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Beverage or Wellbrook Loop?

Postby g1hbe » Sat Jan 07, 2017 4:28 pm

Wow, a 300 meter Beverage! That would be a magnificent beast. I live in a small home in the UK so something like that could never be anything more than a dream, so I obviously cannot comment. However, the Wellbrook is something I've been using for about 15 years. The 1530 (originally bought in about 2002) has been a Godsend to me. I suffered very high noise levels which prevented me from using my random wire antennas on LF/MF. So I bought myself the 1530, installed it at gutter-height at the rear of the property on a small rotator and the noise just went away! And the ability to rotate the loop meant that I could 'edge out' interfering stations when DXing for distant ones. Try doing that with a Beverage!
This antenna failed after about 14 years, but I did not hesitate in replacing it with another Wellbrook, this time the 1530 LN. These loops work well down to VLF, the time signal stations come in very well. I even hear the Christmas transmissions from Grimeton on 17.2 KHz.

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Andy

DanubeBCL
Posts: 168
Joined: Sat Jul 02, 2016 12:39 pm

Re: Beverage or Wellbrook Loop?

Postby DanubeBCL » Sat Jan 07, 2017 5:57 pm

If you have room for a 300 m Beverage don't hesitate. Build it! Of course it is highly directional.
I do not have room for a Beverage, but my lousy 25 m "random" wire already outperforms both my 5 m and even my 14 m magnetic loop. But not in all directions, of course. The loops are better where the wire pattern has its "nulls". And the wire of course performs bad on VLF and LW. Here the loops a better.
If possible, use them both: Beverage for preferred DXing direction and Wellbrook for all directions.
If it had room for a Beverage, I would not hesitate ...
73, Heinrich

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n1kgy
Posts: 8
Joined: Sun Jan 29, 2017 2:10 am

Re: Beverage or Wellbrook Loop?

Postby n1kgy » Sun Jan 29, 2017 3:23 am

DanubeBCL wrote:If you have room for a 300 m Beverage don't hesitate. Build it! Of course it is highly directional.
I do not have room for a Beverage, but my lousy 25 m "random" wire already outperforms both my 5 m and even my 14 m magnetic loop. But not in all directions, of course. The loops are better where the wire pattern has its "nulls". And the wire of course performs bad on VLF and LW. Here the loops a better.
If possible, use them both: Beverage for preferred DXing direction and Wellbrook for all directions.
If it had room for a Beverage, I would not hesitate ...
73, Heinrich


Heinrich makes several good points. back in the 1990s I read all the available information from Bell Labs on Beverage's original work, and have since designed and constructed many Beverages and BOG (Beverage on Ground) antennas for myself and for other hams and SWLs. There are some things you should keep in mind to get the "best" performance from you Beverage antenna -

The beverage antenna develops it's maximum gain when it is between 2 and 3 wavelengths long (depending upon wire height and ground conductivity under the antenna), but the Beverage will have it's sharpest directional selectivity when longer - typically 4 to 6 wavelengths. There is absolutely nothing wrong with having a "jumper" which can disconnect the last 1/4 to 1/3 of the antenna (away from the feedpoint) in order to choose for best directionality vs. best gain - but of course, then you will have to have a proper ground at the selected interim point, and provide a terminating resistor at the interim point as well providing these at the extreme end. Obviously, this gets a lot more complicated with a "reversible" Beverage setup.

The "shorter" beverages of 2 to 3 wavelengths generally don't require a receive pre-amp at their feedpoint when the matching transformer is well made, but it's not uncommon for the longer, "sharper" ones to require a pre-amp in order to obtain best performance in actual use.

Also important to remember is that even though a terminated Beverage is not a "resonant" antenna, it **is** Periodic - meaning that it's gain varies between maxima and minima following a periodic cycle - when the antenna is an odd multiple of quarter wavelengths long - 3/4, 5/4, 7/4, etc. - it has lowest gain; and when it is an even multiple of quarter wavelengths long - 6/4, 8/4, 10/4, etc. - it develops the highest gain.
With "average" soil types and an antenna height of 7~12 feet above ground, the variation in gain may be as little as 2 to 4dB (essentially unnoticeable except under the most marginal circumstances), but with particularly poor soil (solid rock, dry sand, etc.) the periodic variations may be as much as 8 or 10dB, and <b>will be most pronounced near the lower frequency bound of the antenna's directionality.</b>
Fortunately, both of these potential issues can be addressed effectively with a quality pre-amp at the antenna's feedpoint.

So how do I define "quality" with regards to the pre-amp?
1 - It must have a high IP3 (Most Important) ,
2 - it should implement some form of gain-limiting so as to smooth out the variations in signal level at the input - typically this is implemented by powering the amplifier from a controlled-current source, and taking the output as a "Cathode Follower" (a "Drain Follower" in MOSFET terms) across a fixed resistance which matches the impedance of your coaxial line - here's a page on using a tube as a Cathode Follower which will help you get the basic idea - https://www.ampbooks.com/mobile/amplifi ... -follower/

And 3rd, with an unterminated (Bi-Directional) Beverage you want to stabilize the input impedance seen by the amplifier- so it's best to have a resistor directly between the input terminal of the preamp and the signal ground, so that any reactance at the feedpoint of the antenna is swamped by the resistor; otherwise the reactance may ruin the [Beverage + pre-amp's] performance in certain portions of the spectrum, or even degrade the amplifier's stability, resulting in "birdies" (self oscillation) at one or more frequencies. This resistance (and the ratio of the matching transformer) will be determined by the designed input impedance of the preamp, and most likely will not match either the coax impedance or the "antenna impedance" (i.e. it will not be the same as the terminating resistor of a terminated Beverage).

OK, I've said a lot here - feel free to come back with more specific questions.

Cheers

Chuck
n1kgy
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rack201
Posts: 13
Joined: Mon Dec 26, 2016 12:39 am

Re: Beverage or Wellbrook Loop?

Postby rack201 » Sun Feb 05, 2017 5:40 am

Just as an aside, I wanted to buy a Wellbrook loop recently, and Andy Ikin indicated he/Wellbrook Communications didn't have the capacity to manufacture and he was moving towards retirement.. your mileage may vary..
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g1hbe
Posts: 216
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Beverage or Wellbrook Loop?

Postby g1hbe » Sun Feb 05, 2017 10:36 am

Oh dear, Rack. That'll be the end of an era. I was only talking to him a couple of weeks ago and he didn't mention this, I'll have to email him and see what gives!

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Andy

dsalomon
Posts: 51
Joined: Sat Oct 10, 2015 1:50 pm

Re: Beverage or Wellbrook Loop?

Postby dsalomon » Sun Feb 05, 2017 11:52 am

That's not good news. However, there's an alternative that performs nearly the same (or exactly the same): https://www.dxengineering.com/search/pr ... =Ascending

This loop used can also be found at Solid Signal, formerly Pixel Technologies: http://www.solidsignal.com/pview.asp?p=rf-pro-1b

They are the same price. However, I trust DX Engineering much more and have done business with them for many years. I have no idea if either or both ship outside the USA.

Best - David, AG4F

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g1hbe
Posts: 216
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Beverage or Wellbrook Loop?

Postby g1hbe » Sun Feb 05, 2017 2:29 pm

I've just had a reply from Andy Ikin. He says he's not quite retiring yet, but is reducing his range of products. He didn't say which products would be stopped.

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Andy

rack201
Posts: 13
Joined: Mon Dec 26, 2016 12:39 am

Re: Beverage or Wellbrook Loop?

Postby rack201 » Mon Feb 06, 2017 3:55 pm

Its a shame because I was very keen on a Wellbrook - more so than the Pixel based on what I was reading.

My challenge is that I'm based in India so shipping is essentially a no go. I've decided I'll have a go at building my own and have ordered one of the LZ1AQ active antenna amplifier kits from active-antenna.eu.

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