MLA-30 active loop antenna

[vinlove]

Sure. If you can improve the antenna drastically, and you can hear dx stations better, then by all means. Please let us know about it.

But from my experience and feelings, anslysing and improving HF antennas are inseparable from the factors such as what kind of RXing you do, and your Radios and RFI environment.

It seems not very meaningful just discussing the antennas without those conditions. Because, if you are just a causal listener not interested in dxing the weak signals from the remotest corners of the word with small power, then any antenna will copy most signals very well. Even the whip antenna on your portable can rx all these signals very well. And even if you are comparing the whips, longwires and the loops, they will all sound very similar.

It is only when you try to copy Radio New Zealand or any South American low powerd am stations from Europe, the antennas will make difference. And they can be then practically tested. And also your location, type of rig and RFI situations ...etc will all contribute to the performance of the antenna you are talking and testing about.

[A.Z.]

Sure. If you can improve the antenna drastically, and you can hear dx stations better, then by all means. Please let us know about it.

But from my experience and feelings, anslysing and improving HF antennas are inseparable from the factors such as what kind of RXing you do, and your Radios and RFI environment.

It seems not very meaningful just discussing the antennas without those conditions. Because, if you are just a causal listener not interested in dxing the weak signals from the remotest corners of the word with small power, then any antenna will copy most signals very well. Even the whip antenna on your portable can rx all these signals very well. And even if you are comparing the whips, longwires and the loops, they will all sound very similar.

It is only when you try to copy Radio New Zealand or any South American low powerd am stations from Europe, the antennas will make difference. And they can be then practically tested. And also your location, type of rig and RFI situations ...etc will all contribute to the performance of the antenna you are talking and testing about.

You are mixing and matching different things which are unrelated; an antenna is an antenna and can be characterized for (e.g.) its gain and pattern, an active antenna has the additional preamplifier stage, so the performance of the latter should be taken in account, this means considering the noise introduced by the preamp, its IMD characteristics and then some, then, there's also to deal with the feedline which may (and generally will) carry common mode currents and then some; you seem to keep ignoring all these and focus on "what stations" or "which frequencies" which are totally outside the discussion about the antenna system intrinsic noise optimization (reduction), so, feel free to carry on as you like and I hope you're satisfied with your antennas, but I won't follow you in such absurd discussions

best

[vinlove]

Sure. If you can improve the antenna drastically, and you can hear dx stations better, then by all means. Please let us know about it.

But from my experience and feelings, anslysing and improving HF antennas are inseparable from the factors such as what kind of RXing you do, and your Radios and RFI environment.

It seems not very meaningful just discussing the antennas without those conditions. Because, if you are just a causal listener not interested in dxing the weak signals from the remotest corners of the word with small power, then any antenna will copy most signals very well. Even the whip antenna on your portable can rx all these signals very well. And even if you are comparing the whips, longwires and the loops, they will all sound very similar.

It is only when you try to copy Radio New Zealand or any South American low powerd am stations from Europe, the antennas will make difference. And they can be then practically tested. And also your location, type of rig and RFI situations ...etc will all contribute to the performance of the antenna you are talking and testing about.

You are mixing and matching different things which are unrelated; an antenna is an antenna and can be characterized for (e.g.) its gain and pattern, an active antenna has the additional preamplifier stage, so the performance of the latter should be taken in account, this means considering the noise introduced by the preamp, its IMD characteristics and then some, then, there's also to deal with the feedline which may (and generally will) carry common mode currents and then some; you seem to keep ignoring all these and focus on "what stations" or "which frequencies" which are totally outside the discussion about the antenna system intrinsic noise optimization (reduction), so, feel free to carry on as you like and I hope you're satisfied with your antennas, but I won't follow you in such absurd discussions

best

My point is coming from real SWL activities with the real antennas MLA30, lw, and dp and gp.  It is not absurd discussions made of some imaginations.
I am not saying what you are doing is pointless. It is still interesting aspect of antenna theories and practicals.

But you must always also give data, what receivers you have used with the antennas you are working on (I asked you before, and you laughed off making it out as if it were police testing or something like that?), and data on what stations you copied , and where you are located, and your RFI environment descriptions too. If you are located in Italy, and saying that your antenna is copying great for signals from Spain, France or China (1500 kW TX power) or Romania, I would not be much impressed.
I would be impressed, if you were copying R. Clube do Para 4885 kHz, or 3310 kHz Bolivia, 4055 kHz lpam stations or the am stations from South Pacific Islands with 1 -10kW tx power or RNZI.  I would say that your antenna is really working for you, and you have done the great job for improving it etc.

And I would have some more realistic ideas about what you are doing and saying is not meaningless dream catching stories, but some more realistic practical works that can be put into the real RX antennas for HF DXing.

73s

[A.Z.]

please, explain me what the receivers I own, the antennas I use, the stations I receive have to do with optimizing the MLA-30 antenna to reduce its intrinsic noise and improve its performances

[vinlove]

When you say MLA30 is noisy, you must explain what RFI condition your environment of RX.  If you are in a high rise flat with loads people around you running many electrical devices which emits RFI, then yes, MLA30 or any shape and form of antenna will be noisy in both NF and RX.  But if you have an acre of land on the top of the high hill, with no one around you, I am sure MLA30 in the QTH would be quite acceptable in NF.

Also what radios have you connected MLA30 too. If you connect MLA30 to cheap portables with no front ends, yes, it will overload and noisy.  But if you connect it to let say some vintage tube radio, it will be very very quiet.  If you connect it to Icom R75 or NRD 525, then it would be just OK.

I could go on and on, but you get the picture. Without these extra data, antenna mods and tests are not very meaningful. That is my point.  I find MLA30 not great DX antenna from stock, but not bad either.  Trying out different B-Ts did not make much difference. So, I did not see much point trying mod it, and just use it stock.

I use it with R75 and NRD525, and try to RX all those LPAM signals from the locations I mentioned. My QTH is not too bad for RFI and I have a good garden for about 20m long wire antenna.  But as I said, if you could improve it and make better DXing antenna, that would be great. But those extra data for your mods and tests would be much appreciated.

I am saying this, because in the past, I have tried expensive and very highly reviewed antennas with great lab test results and NF figures and all the rest, but when tried in real RXing, it was not much better than my no cost longwire in the garden.  That does not mean that I am ignoring all the lab test results and NF figures on the paper at all.  They are very meaningful but when only supplement with the extra practical data from the RX.

[A.Z.]

you haven't the palest idea about intrinsic preamp/supply noise and common mode noise, do you ?

heh

[vinlove]

you haven't the palest idea about intrinsic preamp/supply noise and common mode noise, do you ?

heh

Please stop trying to be cute. It's not funny.

[A.Z.]

ok, so please, pick the MLA-30 preamp and bias-t and run a series of tests to characterize its intrinsic noise, then come back here and show your results

goodbye

[vinlove]

Sure, the most important thing with your RX antennas, what they can hear, not how quiet they are.
I am not sure, if you are doing any SWL and BCL DXing on HF.

Because if you do, you would have noticed, that even the noisy longwire can turn to very nice quiet antenna pulling good signals from DX locations depending on the band condition.
And even the most quiet antennas can turn to noisy, if there are disturbance such as sporadic E, aurora or if they are placed in strong RFI farm area, then it will wipe out your RXing totally with noise.

So, in the lab testing conditions of the antenna, I am not sure how your settings are in measuring the NF noise and all these.  Without all the factors being considered and tested, it would be quite meaningless to say, this antenna is noisy or quiet.

So, supplement with the extra practical data and it would be a lot more convincing and meaningful project.
For me, as I have told you, I have tested out a few B-Ts with MLA-30, and I couldn't notice significant improvement in pulling the DX signals I was trying to hear with all the options, hence I went back to the original MLA30 B-T.  It was just ok as is, and concluded my effort for mods will not significantly improve the DX RXing capability.
I would rather try out different antennas such as Wellbrook or EWE or Mini Beverage or verticals.

But I will keep update with what I find from own practical tests and experiments. I think your mods ideas also interesting stuff. It is just I have different ideas and point of view on it, and we can see the whole picture from different angles. I am not rubbishing your ideas and efforts for improving MLA30.  Please update with your ideas and tests and practical results, and they would be very helpful. Thanks 73s

[A.Z.]

For me, as I have told you, I have tested out a few B-Ts with MLA-30, and I couldn't notice significant improvement in pulling the DX signals

I'll repeat it for the last time, then I'll stop; the modifications to the BIAS-T are aimed at reducing the INTERNAL noise which it generates, the same goes for the other modifications; lowering the noise floor will give better reception, plus it may and usually will help pulling out very weak signals which, otherwise, would be lost in the noise; now, while there's nothing one can do about propagation, there's quite a bit of things one can do to optimize his antenna system, that's what I'm trying to do with the MLA-30, applying some cheap and easy modifications which, by reducing its internal noise improve its performances; just to say, days ago I was listening to a VK ham station on my LLD (Linear Loaded Dipole) antenna and decided to try the "stock" MLA-30, well, the station was still there but was barely readable due to the noise introduced by the BIAS-T, replacing the BIAS-T with another one I have lowered the noise and improved the readability of the signal, see what I mean, now ?

I already posted a couple images of the spectrum as seen using the LLD and the MLA and it's easy to see what my noise floor is and how, the noisy BIAS-T raises the noise floor a lot, but since that may be easily cured by either modifying the stock BIAS-T or by replacing it, it's what I'm doing (and then some more, since there are other cheap and easy mods to further improve it)

[vinlove]

I will also repeat for the last time. I am not saying the internal noise of the antenna is non relevant.
But the more over riding factors in HF Rxing are, all the points I have listed to you above.

I mean for one example out of many factors, if you connect the improved low internal noise MLA30 to 30$ portable radio, it would be very noisy and overload it.
If you connect it to a Drake R8E, then it would be great.  So, what radios are you using, I asked.

It is not just active antennas generate internal noise. The radios also generate internal noise. The atmosphere generate the noise, so do all the electric appliances you are running.
So, it is just a factor in DXing HF, but I don't feel it is a major factor. It is a minor factor from my tests with the other high quality B-Ts and MLA30.

You should keep discussing your points without emotionally upset in technical topics like this. Because we are not talking about you or me, or your or my knowledge, but just simple technical and practical facts here.

[A.Z.]

I mean for one example out of many factors, if you connect the improved low internal noise MLA30 to 30$ portable radio, it would be very noisy and overload it.

You keep changing the object of the discussion, we were talking about the MLA-30 antenna NOT about whatever receiver you connect to it, once the antenna is working at its best, there are OTHER ways to deal with some POOR receiver which gets overloaded, I understand that you're curious as for what receiver I use, well, I can make a list of some of the receivers I used, starting from my very old Geloso, to the FRG-7, IC R75, Kenwood R2000... but does this add something to this topic ? Absolutely NO, so stop trying to sidetrack the discussion and focus on the ANTENNA, not about whatever else is going down the road.

[vinlove]

Any antenna without receiver connected is totally pointless. What can you know or say about it, apart from how it looks?

If I say to you here is an antenna. Its gain is 1000 dB and NF is none.  But without connecting it to a radio, and RXing the signals coming from the live AM stations from all corner of the Earth, what can you say about it?

It is not change of the topic, but suggestion to supplement with the vital practical data, and make it more complete. That was just a suggestion, but you seem rather taking it too personally unduly over reacting to it.

[vinlove]

I now have 2x MLA30, longwire, dipole and Wellbrook ALA1530 for HF RXing.

After RXing for DX signals with all those antennas switching in-between, I cannot honestly say that noise floor figure is a major problem for DXing the weak signals on HF.

It more boils down to where the antennas are setup, where the antenna is pointing to in case of directional antennas and the band conditions.  Even more quiet antennas at one time becomes totally noisy, and vice versa. (noisy longwire becomes nice quiet Rx antenna at times)

They are all great RX antennas at one day and a time, and the next day it becomes noisy and useless, and the other antennas do better.

So with all the factors involved in HF RX and DXing,  NF figure is just a minor point, which one must take not too seriously.  If the condition is good, even a built-in telescopic whip does work well.  Other times, even the most expensive and high gain and quiet antennas turn to noise catcher.

Best thing is, to have as many different type of antennas one can manage and afford in space and budget. Switch over all the antennas for the best signals on the station you want listen to.

[unikt]

Hello everyone! I have one of these antennas and I really like it. I replaced the original antenna element with an aluminum foil covered hula hoop and I also plan to get the bias tee from a mini whip instead of the original one.

This is not why I posted however. I found this on ebay, which claims to be better than the MLA-30, I ordered one and will try it out. But I wondered what you think? Can it be better?
https://www.ebay.com/itm/AMLA150-Magnetic-Loop-Antenna-Adjustable-Gain-Low-Noise-For-FM-HA-SDR-Radio/154058572374

[vinlove]

From this test vid. I highly doubt if it will be much different performance from MLA30.


But please update us with your findings once it arrives and you have done some DXing tests with the antenna.
Thanks

[vinlove]

The reason I am skeptical on the antenna for better than stock MLA30 is that, (I am repeating this yet again )

1. There are so many other factors which influence the noise floor figures and the performance of the antennas.

2. The major points for it are,
The band condition
The Antenna set up, location (how high low or near the building or clear in the field) and environment
RFI condition (How bad RFI saturation is in the vicinity of the antenna
And even type and length of the antenna element (smaller and shorter element tend to be quieter than larger and longer element)
And the noise generation of the receivers ... etc etc.

So it is meaningless to say, oh this antenna has quiet NF figures in the lab test results, so it must be better antenna.
And how well can it copy the weakest DX signals from the most distant locations from your RX site?
Perhaps this is the most important question on the DXing antennas, be it MW LW or HF.

MLA30 with the stock B-T, and another MLA30 with high quality B-T from AOR, ok on testing environment, it seemed the MLA30 with the high quality AOR B-T sounded quieter.
But in the real RXing condition? They were similar. They were both overrun by QRM, if the band condition gets noisy. Both got noisy equally under bad RFI condition too. And copying the weak DX signals? They were kinda same, no much huge difference between the two.

So, rather than spending time and money and energy for modification, I went for just buying different type of antennas = a vertical and another Active Loop.
Time is money, and sometimes it is better to just buy different and better product than modification efforts.

[A.Z.]

So it is meaningless to say, oh this antenna has quiet NF figures in the lab test results

Do you own an SDR receiver (even a simple RTL-SDR one) ?

[vinlove]

Yeah I have a SDRPlay RSP1A.

[A.Z.]

Yeah I have a SDRPlay RSP1A.

Fine, so please, try running a very simple experiment; since you wrote you have several antennas, plug the SDR and set it to a band, say the 20m one (14MHz), connect a passive antenna and tune in to a weak signal (or even a free frequency in the band), then take a snapshot of the waterfall/spectrum, now, switch to another antenna and take another snapshot, repeat it with your other antennas, including the stock (standard bias-t) MLA-30 and, if you want, an alternate BIAS-T too, then post the pics here, it will be interesting to see them

[A.Z.]

Hello everyone! I have one of these antennas and I really like it. I replaced the original antenna element with an aluminum foil covered hula hoop and I also plan to get the bias tee from a mini whip instead of the original one.

This is not why I posted however. I found this on ebay, which claims to be better than the MLA-30, I ordered one and will try it out. But I wondered what you think? Can it be better?
https://www.ebay.com/itm/AMLA150-Magnetic-Loop-Antenna-Adjustable-Gain-Low-Noise-For-FM-HA-SDR-Radio/154058572374

first of all, I'd try running some fat copper wire or some of them in parallel inside the hula hoop, I suspect the signal may improve a bit

as for the other antenna, don't know what to say w/o a schematic, but sincerely I won't expect "stellar" performances from it

[vinlove]

Yeah I have a SDRPlay RSP1A.

Fine, so please, try running a very simple experiment; since you wrote you have several antennas, plug the SDR and set it to a band, say the 20m one (14MHz), connect a passive antenna and tune in to a weak signal (or even a free frequency in the band), then take a snapshot of the waterfall/spectrum, now, switch to another antenna and take another snapshot, repeat it with your other antennas, including the stock (standard bias-t) MLA-30 and, if you want, an alternate BIAS-T too, then post the pics here, it will be interesting to see them

No need for that.
I told you time is money.  I would rather listen to the band with my radios and antennas looking for interesting exotic DX signals, rather than fiddling about with the SDR screen captures. That is not fun.

[A.Z.]

Yeah I have a SDRPlay RSP1A.

Fine, so please, try running a very simple experiment; since you wrote you have several antennas, plug the SDR and set it to a band, say the 20m one (14MHz), connect a passive antenna and tune in to a weak signal (or even a free frequency in the band), then take a snapshot of the waterfall/spectrum, now, switch to another antenna and take another snapshot, repeat it with your other antennas, including the stock (standard bias-t) MLA-30 and, if you want, an alternate BIAS-T too, then post the pics here, it will be interesting to see them

No need for that.

I see, well, thank you anyway, your reply is still very useful and eye opening

[vinlove]

I see, well, thank you anyway, your reply is still very useful and eye opening

If the improved B-T fed Active Antennas can be also improved on DXing performance, it would be worthwhile effort to go and mod or replace the stock MLA30 B-T with better ones.  But from my testing, it was not really making noticeable difference in DXing after with better B-T paired with MLA30.  So, what is the point? I thought. I just went back to the stock B-T for the MLA30.

As day and time changes, so does the HF propagation and noise level in the atmosphere, and sometimes the longwire with tuner works better, sometimes MLA30s, and mostly the Wellbrook works better.  So, I thought have as many antennas as I can fit into my space, and use the best one for the propagation at the time. But the improved B-T NF noise figure cannot override the noise in the atmosphere and band condition. That was my conclusion.

I still would be interested to see your modded and improved MLA30 update, but with the practical test results what it was able to receive, and how it is different from the stock B-T, if you would update it.  But if not, it is OK. Thanks 73s.

[A.Z.]

As day and time changes, so does the HF propagation and noise level in the atmosphere

But not the internal noise generated by a badly designed antenna; I asked you to show your noise floor on the various antennas (it would take seconds), but you denied and you're going on talking about fried air, so I must thank you again for this post which is another good eye opener