South African Reader Compares Antennas
Wellbrook ALA1530 vs. RF Systems DX-One Pro Mk II
John Plimmer, Antenna Sleuth
On LF (longwave) the DX-One Pro hears things that are unheard on the ALA. For example, 515 kHz CW, MAJ Majuba is quite clear on the DX-One but not heard on the ALA1530, and the same is true with various others. 252 kHz Algeria is faint on the DX1 but unheard on the ALA, while 361 kHz CW ASN Ascension is clear on the DX-One but barely audible on the ALA.
Results are more or less the same on MW (AM) band. The DX-One is much clearer and stronger: thus, 1050 kHz Brazil is quite clear on the DX-One but unreadable on the ALA.
Then I worked the HF (shortwave) bands from 3 MHz up to 18 MHz. Here the DX-One remains the stronger and clearer with world band signals, but the ALA also puts in a good performance.
RFI and noise suppression: I didn’t notice that the ALA was quieter with noise than my DX-One, nor does it suppress the harsh RFI I have here. I did spend half an hour with the assistance of helpers rotating it in various directions, but it could not suppress the local RFI noise.
I have always had the opinion that the DX-One is a superior performer, as I have had some outstanding catches over the years. And so it proved to be. For more info on my DX-One, see here.
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-7700, Icom IC-756 PRO III with MW mods
July 16th, 2009 at 2:44 AM
It’s great the DX-One has worked for him. But really if you are financially able to buy multiple antennas selected for their characteristics applicable for your location and undergo testing, then that would be best.
This is what is so frustrating about antennas. I had not much money so I bought the ALA1530 based on reviews. The ALA1530 sometimes is able to null noise in an urban environment if it’s in one direction. Right now in Helena, Montana, USA, I live in an apartment that is about 20 feet from a huge collection of power meters, and there is an utility closet with several water heaters next to my place. So if I try to null that, then I run smack into 1240 kHz KBLL and 1340 kHz KCAP towers about 1 or 2 miles away.
The E1XM shows 1240 and 1340 pegged 60 dB over S-9 when nulling the local noise. If I null the mediumwave AM stations, I can get them down to 20 to 40 dB over S-9, but then the local noise is very loud. The stations on 1240 and 1340 also overload either the ALA1530 or the E1XM. If I use the built-in telescopic antenna, I don’t hear this, but if I use the ALA, then I hear it. I was not sure if the ALA simply makes the radio quiet enough to hear the overloading or actually generates it.
Unfortunately, I have pretty much stopped listening to HF/shortwave now because I have too much noise. Now, on the other hand, my Collins R-390A definitely does not overload at all; I got mine from Chuck Rippel. What I really would like is a Wellbrook with multiple steerable nulls and a narrowband amp and programmable filtering of both frequency and attenuation level for, say, $500 or less and for an small urban space.
Ed.: A key consideration with antennas, like real estate, is location. This applies whether the antenna is passive or active, and can’t be stressed enough. Local electrical noise, a growing curse, makes this all the more important.
July 16th, 2009 at 1:54 PM
I have never had the pleasure of owning a DX-One, but I do own an indoor Wellbrook LA 5030 loop antenna. I had two issues, RFI and space. Putting antennas outside is problematic due to community restrictions, so my antennas have all been in my attic. The LA 5030 has ably tackled both issues well.
The RFI was a generalized interference that was on a number of frequencies. I tried shutting off my computer and other items with no appreciable effect. I bought a MFJ 1026 to help and it would null out a specific source, but then I would run into more just a little bit up the dial. The LA 5030 was able to knock down the level of interference across the bands, and with the use of the an antenna rotor I am able to null out the few remaining offenders. Since using the LA 5030 I have been able to pull in stations that I couldn’t hear at all on either my Etón E1 or AOR AR7030+ receivers.
I do agree completely with the previous editorial comment. Prior to purchasing the LA 5030 I moved my two existing antennas around to other locations with some minor improvement, but not enough for my needs.
July 24th, 2009 at 2:21 AM
I have owned the DX-one Pro MK11 for a few months now and I have to agree with John Plimmer,
The RF Systems antenna is unreal.
Over the last 30 years I have tried most active antenna’s, long wires of differing lengths and dipoles etc. The Dx One is very quiet, that is the first thing you will notice, I connected it up and thought I had bought a dud antenna, I tuned the Icom IC-R75 to our local AM station ( 144 kilometres to my west ) the S meter showed full deflection, the gain control on the DX-one was on “0″ gain so I knocked it back to -40db, the Icom meter was still 20 over S9. I thought this cannot be right so I switched over to my 100 meter longwire ( north west to south east direction ) with a MLB connected, it read 10 over S9, I found it unusual that an active would out do a 300 foot long wire.
I tried another test, this time on a DRM signal from New Zealand, so I patched the DX-one into the Winradio G313e and dialed up on 7285 Khz, signal was good at S9, this is with -40db attenuation mind you and bang in came the decoded DRM with a signal to noise ratio of 21, which is more than perfect, 18 was my previous best on a Datong Active antenna, I reduced the attenuation to 0 on the DX-one, signal was now 20 over S9 with a small rise in the floor noise, this inturn dropped the SNR to 19, which is still very dam good.
I now plugged in the long wire and changed nothing else on the radio, Radio New Zealand was now at S8 and the noise foor was a lot higher, the DRM started to decode but it was spasmodic and kept on dropping out SNR,was at 8 & 13. I did get the SNR to 16 by tighening the filters, but this introduced other problems with the decoding.
I summary, I am very, very pleased with my purchase. I tried to search on the net for info on the DX-one but there was not a lot of information available, I came across John Plimmer’s article and that did help with my descission to purchase the DX-one, the next shock was parting with the cash. The DX-one was purchased from Haydon Communications in England and it took 2 weeks to get to me here in Tasmania, Australia.
I can understand why this antenna is so expensive, why, because it is the best ( in my location anyway ) If you do buy one, read the instructions carefully, take good note of the earthing instructions and you will really enjoy the 0-30Mhz bands.
Regards
David French
Tasmania, Australia
August 2nd, 2009 at 11:47 AM
I cannot be so positive about the DX One Mark II. I have had mine for several years and it has never worked during that time. I am now convinced that the preamplifier in the roof-mounted antenna component is damaged or otherwise defective, since the control unit seems to operate as designed. The problem with this system is, of course, that there is nobody in the US who can repair it, including Universal Radio, the only seller in North America, and returning it to RF Systems in the Netherlands is costly. Anyone purchasing this system should be aware that service may become a problem.