Re: comparing Wellbrook earlier ALA1530 to later ALA1530LN
I haven't compared the ALA1530S+ with any other ALA1530.
But for general information on Wellbrook loop amps, all the ALA1530 line were designed for a small one-meter diameter loop. All the ALA100 line were for much larger loops. All the FLG100 line were for terminated loops with approximate 800 ohm impedance.
Steve
toggle quoted message
Show quoted text
On 7/26/2024 9:13 AM, enriqueeeeee2001 via groups.io wrote: Has anyone compared the 1530LN with the 1530S+? Which is better?? Ihave still got in use an ALA100M with a 1x1 metre squared loop it works quite good till now.
Also, I am very lucky and I have a brand new ALA100FLGLN module with the active feeder, I have no space since I live in a flat. I hope some day I will try it.
Now , I have the chance of gettin a 1530S+ but I do not know if getting it, maybe a Wellgood could solve the situation just in case my 100M stop working.
|
Re: comparing Wellbrook earlier ALA1530 to later ALA1530LN
Has anyone compared the 1530LN with the 1530S+? Which is better?? Ihave still got in use an ALA100M with a 1x1 metre squared loop it works quite good till now.
?
Also, I am very lucky and I have a brand new ALA100FLGLN module with the active feeder, I have no space since I live in a flat. I hope some day I will try it.
?
Now , I have the chance of gettin a 1530S+ but I do not know if getting it, maybe a Wellgood could solve the situation just in case my 100M stop working.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Caarlo please do not focus exclusively on the active loop antenna. See your local conditions, the earthing system, the feeder cable more broadly as an interactive system. There might be other reasons, which may also be responsible for the noise ingress. Play around with common mode chokes and different earthing connections. Is the SNR better, if you connect your loop with a short cable to a (floating) standalone SDR nearby?
?
regards
Fred
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Hi Caarlo, Did you try to rotate it? For some stations my EFHW is better, for other Loop is better (on different bands - switching with A/B coax switch). But I'm still planning to put it on rotator to do a better 1:1 comparison. It's not easy with all the fading and etc. Needs to be done remotely with rotator and not by hand. Regards, Simon On Thu, Jul 25, 2024 at 4:25?PM Caaarlo via groups.io <caaarlo@...> wrote:
On Thu, Jul 25, 2024 at 03:34 PM, rfsam wrote:
but a still can see a bit of SNR increase.
Hi Sam,
Thanks for the suggestion, but I need a more noticeable SNR increase than just a bit. Right now it is some 3-6dB behind my full sized antennas, and my initial goal was to outperform the SNR of these antennas, so I need at least a 6dB improvement.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
On Thu, Jul 25, 2024 at 03:34 PM, rfsam wrote:
but a still can see a bit of SNR increase.
Hi Sam,
Thanks for the suggestion, but I need a more noticeable SNR increase than just a bit. Right now it is some 3-6dB behind my full sized antennas, and my initial goal was to outperform the SNR of these antennas, so I need at least a 6dB improvement.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
On Thu, Jul 25, 2024 at 02:29 PM, Martin - Southwest UK wrote:
Hi Caaarlo,
?
How many ferrite snap-ons did you add ?
?
With just one pass of the coax, you would probably need 20 or more, before you might notice any difference at HF frequencies.
?
Hi Martin,
I used a couple on each end. With a just a couple of these same snap-ons on the PC supply cable solved a problem with my WebSDR, as there were some very noticeable periodical strips along the spectrum.
But now, with the LZ1AQ I don't see any , just a lot of noise. So, it turns very hard to identify and diagnose.
Insrerting the transformer should almost completely eliminate any common mode coupling, but the problem remains even with the transformer.
?
I had a similar problem with the Miniwhip, which it is reasonable for this kind of antenna, as the miniwhip lacks filtering, has almost infinite input impedance and is prome to common mode coupling, increasing noise floor due to IMD.
?
?
However, I suspect your problem is due to direct RF radiation from the interference source(s). In which case there is unlikely to be a "miracle" antenna that will work. Your best bet is to find the quietest location you can to site the antenna, and then use it's directional properties, to try and "null" out the worst of the remaining interference.
?
If that was the problem, then I would be in the same situation with my full size antennas. These pick up a lot of noise, but not as much as my LZ1AQ. And considering my LZ1AQ has a decent input filter with a "narrow" window of only 5MHz, I should be able to easily spot the interference just by looking within those 5 MHz of pass band.
?
I don't know. I'm running out of ideas. Might try some illogical things like replacing the input filter by the default filter proposed by LZ1AQ and see how it behaves.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Hi Martin and Caarlo, Did that for my LZ1AQ: 2 stacked FT240-31 with SFTP CAT-8 wrapped around. I think it helped a bit compared to just a snap one single (but thick) ferrite. Regards, Simon On Thu, Jul 25, 2024 at 10:29?AM Martin - Southwest UK via groups.io <martin_ehrenfried@...> wrote:
Hi Caaarlo,
How many ferrite snap-ons did you add ?
With just one pass of the coax, you would probably need 20 or more, before you might notice any difference at HF frequencies.
Several turns, though, a ferrite ring is more economical in terms of materials and performance.
The chart on Steve G3TXQ's webpage is a handy reference guide.
However, I suspect your problem is due to direct RF radiation from the interference source(s). In which case there is unlikely to be a "miracle" antenna that will work. Your best bet is to find the quietest location you can to site the antenna, and then use it's directional properties, to try and "null" out the worst of the remaining interference.
Regards,
Martin
On Thu, Jul 25, 2024 at 04:44 PM, Caaarlo wrote:
FInally, almost hopeless, I placed some ferrite snap-ons, on both ends of the cable, but this did not help either.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Hi Martin, Thank you! That's great to know! Simon On Thu, Jul 25, 2024 at 2:33?PM Martin - Southwest UK via groups.io <martin_ehrenfried@...> wrote:
Ideally you need to model it to see for yourself what the pattern looks like, but the gain is within a few dB, until the elevation drops below about 15 degrees, then it falls off more rapidly.
This is much less of an issue for reception purposes, than it is for transmission, so I wouldn't worry about it.
A LOG has a different pattern, so it may work better or worse than the smaller loop, depending on your layout.
I used a LOG when I lived in a rural location, and it outperformed my best broadband 'fat' loop mounted at 2m AGL. But when I moved back into an urban location, the same LOG was a much worse performer, and I don't use it any more. This was partially due to different soil conditions, and partially due to the type of interference and its direction of arrival.
Regards,
Martin
On Thu, Jul 25, 2024 at 05:54 PM, rfsam wrote:
Near the GND loop will become NVIS even for higher bands but I assume
that shouldn't affect SNR (which we care about mostly) much until
signal level becomes very low?
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Ideally you need to model it to see for yourself what the pattern looks like, but the gain is within a few dB, until the elevation drops below about 15 degrees, then it falls off more rapidly.
?
This is much less of an issue for reception purposes, than it is for transmission, so I wouldn't worry about it.
?
A LOG has a different pattern, so it may work better or worse than the smaller loop, depending on your layout.
?
I used a LOG when I lived in a rural location, and it outperformed my best broadband 'fat' loop mounted at 2m AGL. But when I moved back into an urban location, the same LOG was a much worse performer, and I don't use it any more. This was partially due to different soil conditions, and partially due to the type of interference and its direction of arrival.
?
Regards,
?
Martin
?
?
On Thu, Jul 25, 2024 at 05:54 PM, rfsam wrote:
Near the GND loop will become NVIS even for higher bands but I assume
that shouldn't affect SNR (which we care about mostly) much until
signal level becomes very low?
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Hi Caarlo, Sorry for asking but have you tried cross-parallel loop configuration with two 1m loops? Maybe worth a try. I have commercial LZ1AQ, so I can quickly click relays and see the differences. In my situation (loop is outside on the 2nd floor balcony) I see almost no difference between LoopA vs LoopB, but there is a difference between A+B vs A or B. Yes, both Signal and noise go up with A+B, but a still can see a bit of SNR increase. Regards, Simon On Thu, Jul 25, 2024 at 9:44?AM Caaarlo via groups.io <caaarlo@...> wrote:
Ok, I guess I am losing the battle.
Last night I tested a smaller loop (0.5m diameter) hoping that the lower pickup level will increase linearity and improve SNR. But SNR did not change. Pickup levels were 10-15db lower, both signal and noise, so SNR remained the same. Tried different locations and orientations, but none produced better SNR than my full size antenna.
Placing the loop horizontally worsened the SNR. Of course this was 1.5m above ground perhaps. Could not clamp it to the tower yet.
FInally, almost hopeless, I placed some ferrite snap-ons, on both ends of the cable, but this did not help either.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Hi Martin, Near the GND loop will become NVIS even for higher bands but I assume that shouldn't affect SNR (which we care about mostly) much until signal level becomes very low? Martin, how would you compare SNR of not a huge LOG (about 20-25m circumference) placed on the same small garden lot where I can place an MLA (with LZ1AQ or Wellbrook clone)? I don't have much space to play with, unfortunately. Assuming same noisy urban conditions? I bought CCW Experimenters amplifier with BOG/LOG input to try with LOG across my fence. Haven't tried it yet. Wonder if it's even worth the trouble. Thank you, Simon On Wed, Jul 24, 2024 at 10:05?AM Martin - Southwest UK via groups.io <martin_ehrenfried@...> wrote:
If you are mounting it vertically, height doesn't matter too much, and I wouldn't bother going higher than about 2m AGL.
The advantage of small antennas, is that you can often place then in electrically quiet locations, that would not be possible with much larger ones.
For reception purposes, it is the Signal to Nose Ratio that is important, and not the overall signal strength.
Regards,
Martin
On Wed, Jul 24, 2024 at 12:17 AM, Caaarlo wrote:
So far, the best location is slightly above ground in my backyard/garden with a bit worse SNR than my full sized dipoles. Perhaps, it's not a matter of height, but proximity to AC aerial distribution intead ?
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Hi Caaarlo,
?
How many ferrite snap-ons did you add ?
?
With just one pass of the coax, you would probably need 20 or more, before you might notice any difference at HF frequencies.
?
Several turns, though, a ferrite ring is more economical in terms of materials and performance.
?
The chart on Steve G3TXQ's webpage is a handy reference guide.
?
?
However, I suspect your problem is due to direct RF radiation from the interference source(s). In which case there is unlikely to be a "miracle" antenna that will work. Your best bet is to find the quietest location you can to site the antenna, and then use it's directional properties, to try and "null" out the worst of the remaining interference.
?
Regards,
?
Martin
?
On Thu, Jul 25, 2024 at 04:44 PM, Caaarlo wrote:
FInally, almost hopeless, I placed some ferrite snap-ons, on both ends of the cable, but this did not help either.
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
Ok, I guess I am losing the battle.
?
Last night I tested a smaller loop (0.5m diameter) hoping that the lower pickup level will increase linearity and improve SNR. But SNR did not change. Pickup levels were 10-15db lower, both signal and noise, so SNR remained the same. Tried different locations and orientations, but none produced better SNR than my full size antenna.
?
Placing the loop horizontally worsened the SNR. Of course this was 1.5m above ground perhaps. Could not clamp it to the tower yet.
?
FInally, almost hopeless, I placed some ferrite snap-ons, on both ends of the cable, but this did not help either.
|
|
|
Re: Proper transient protection for Ethernet antenna feedlines.
Sorry for the delay in replying to my thread.
I went in for a routine follow up for my knee surgery and the surgeon is really concerned about the swelling of my right calf, so I had the joy of a non invasive ultrasound scan to look for blood clots.
The joy comes from the fact they must store the coupling gell in a freezer!
The radiologist nearly had a heart attack when I took one of my Geiger Counters in to get some idea of the back scatter. It overranges at 1 million counts and sounds a 'buzzer." Each of the 3 X-rays zapped me for 1/10 of a second and each one overranged the Geiger.
?
OK back to the point in question.
Around here, Jessamine County Kentucky, the insurance companies look for any reason to not pay.
?
Oh a tree was blown loose and traveled 1000 feet, act of God.
?
They talk to neighbors, do a social media search. I've already mentioned I have a CCW dual polarity with a Ethernet cable feed.
https://www.crosscountrywireless.net/CCW_HF_Active_Vee_Antenna_Operating_Manual.pdf
One half died but I found a broken wire inside so I wanted to put it back into service located well away from the "EMI bubble" that surrounds my home.
I can always replicate the exterior Ethernet to coax I used in our old home, but, I'd hoped for something a bit less kludgy.
?
The insurance inspector showed up at the same time as the electrical inspector, our new home had been rewired.'
The inspector balked at my use of Tii "F" to "F" transient protectors designed for cable TV.
I pointed out the NEC requires the shield be bonded to ground and the Tii's were my "static blocks," any transient protection is icing on the cake.
?
It is interesting that CCW appears to have dropped Ethernet feedlines.
?
?
I'm still trying to decide if Ethernet cable is 'better' then coax. I can say from an ease of wiring, coax beats Ethernet hands down.
?
?
Our home is wired with coax for cable TV to every room, since my wife and I consider TV to be the spawn of Satan, we use the coax for Ethernet.
And yea Ethernet coax is 50 ohms but 75 ohms works fine in our home.
I use these to convert standard Ethernet ports to coax.
?
The only problem is our security cameras feature power over internet and the above adapters required some finagling.
?
It is interesting that CCW appears to have dropped Ethernet feedlines.
For the young,
https://en.wikipedia.org/wiki/10BASE2
I have several 10Base2 routers. [The phrase packrat or hoarder might have been coined for me. But hey I got rid of just over 2 tons (really 4,000 pounds) of stuff.]
?
YMWV but I've found 10Base2 to have a lower EMI footprint then Ethernet over twisted pair. We use it for file transfer and printing.
Just because tech is old doesn't mean it's ready for the scrap yard.
?
I'll probably recase the CCW antenna to use coax.
?
?
?
|
When Wellbrook was in business I used to buy a new FLG100LN every year due to nearby lightning discharge zapping it. Now I make my own, using one of Everett's boards. My current one died last week--there was a nearby discharge that came over before I could go out and disconnect everything. I repaired it today, second time I've repaired one. This had 3 bad jfets on one side and one bad jfet on the other side. Both bipolars were good. You have to remove all the jfets before you can find the bad ones. I use an inexpensive tester, "TC1", that does a good job testing jfets (and lots of other things too, of course).
73,
Steve AA7U
|
Re: Urban HF Antenna Dilemma: LZ1AQ vs. M0AYF
If you are mounting it vertically, height doesn't matter too much, and I wouldn't bother going higher than about 2m AGL.
?
The advantage of small antennas, is that you can often place then in electrically quiet locations, that would not be possible with much larger ones.
?
For reception purposes, it is the Signal to Nose Ratio that is important, and not the overall signal strength.
?
Regards,
?
Martin
?
On Wed, Jul 24, 2024 at 12:17 AM, Caaarlo wrote:
So far, the best location is slightly above ground in my backyard/garden with a bit worse SNR than my full sized dipoles. Perhaps, it's not a matter of height, but proximity to AC aerial distribution intead ?
|
Re: Proper transient protection for Ethernet antenna feedlines.
Copper to fibre convertors are cheap, and so is fibre.
?
If you factor in the cost of the decent external copper Ethernet cable, and associated protective devices, fibre may work out to be less costly.
?
At my old workplace, we had two separate buildings, about 100m apart, which were fed from separate mains substations, so they needed to be galvanically isolated from each other.
?
We needed to feed broadband RF signals between the buildings, and used direct burial coax, with a ducted cable route, that also carried fibre in order to provide network connectivity.
?
In order to isolate the coaxes, we had installed capacitive, coaxial isolators, in outside shelters, at each end of the coax run. The coaxes were separately grounded from the building earths, so that no DC or AC current could flow between the coax termination points inside the buildings.
?
We had gone to a lot of trouble and expense to comply with the electrical regulations, whilst at the same ensuring that the bi-directional RF signals, ranging from near DC to >3GHz, were degraded as little as possible.
?
So it was a bit disappointing, when we opened up the underground ducts one day, to find that another contractor had run some thin multicore cable, intended for internal alarm use, between the two buildings using the ducts as an easy access route, and in a single stroke had completely negated all of our previous work. The multicore had been installed, so that the reception desks in each building could remotely raise the site entrance barrier. We complained about the shoddy installation, but the company involved refused to acknowledge that there was an issue, and the non-technical staff in the security department who employed them, couldn't understand why there would be one either.
?
It's strange how many times those cables failed...
?
Regards,
?
Martin
?
On Wed, Jul 24, 2024 at 03:00 PM, Raphael Wasserman wrote:
From engineering prospective, having less headackes, by running a fiberoptics cable between two buildings with electro-optical convertors is the best solution.
However, it might cause a financial burden for the customer.
|
Re: Proper transient protection for Ethernet antenna feedlines.
?
The best way to protect the loop amp is to use a relay to short out the antenna input when transmitting. Most transceivers have a key out that can be used to kill the power to the loop amp, which will then short out the antenna input on the loop amp
?
Everett N4CY
In a message dated 7/24/2024 10:00:43 AM Central Daylight Time, wassermanr46@... writes:
?
Martin,
?
From engineering prospective, having less headackes, by running a fiberoptics cable between two buildings with electro-optical convertors is the best solution.
However, it might cause a financial burden for the customer.
I misunderstood his application completely? by using muliple pair ethernet cable - there will not be a transfer of data at all but a remote control between the loop antenna and radio. I looked at closer the designed SPD for Ethernet cables: basically there is no RF filtering but gas discharge tube protectors between leads and common ground terminal. They cannot effect DC control leads. Of course, should be considered a parasitic shunt capacitance for RF signal.
?
Raphael
|
Re: Proper transient protection for Ethernet antenna feedlines.
Martin,
?
From engineering prospective, having less headackes, by running a fiberoptics cable between two buildings with electro-optical convertors is the best solution.
However, it might cause a financial burden for the customer.
I misunderstood his application completely? by using muliple pair ethernet cable - there will not be a transfer of data at all but a remote control between the loop antenna and radio. I looked at closer the designed SPD for Ethernet cables: basically there is no RF filtering but gas discharge tube protectors between leads and common ground terminal. They cannot effect DC control leads. Of course, should be considered a parasitic shunt capacitance for RF signal.
?
Raphael
|
Caaarlo
Everett N4CY