I second the Elad. I have it and it is a solid performing SDR. Very compact and well built.
On Tue, Jan 4, 2022 at 10:27 AM Alberto I2PHD < i2phd@...> wrote: May I suggest also the Elad S2 ?
I have both the Perseus and the Elad S2, and have performed A/B comparisons, and to my ears they perform similarly.
The Elad S2 is quite sensitive down to 10 kHz. I have used it last Christmas Eve to receive the annual SAQ transmission, and you can see the results here :
And the Elad S2 is about half the price of the Perseus....
73? Alberto? I2PHD
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Hi, The Elad S2 is an excellent HF SDR receiver but not always or everywhere. It outstands in urban areas and close to strong signals. But in low noise environment areas, other less expensive SDR can be equally successful or even beat it. Look this test I made on FM Band (the video is conclusive!). Here:? 73's --
Jorge Garz¨®n (EB7EFA ¡¤ EA1036 SWL)?
QTH: IN83ag / 43?15' N ¡¤ 03?56' W
Urb. San Roque 95, casa 5 (Villasevil)
39698 Santiurde de Toranzo (ESPA?A - SPAIN)
..................................................................................
Blog:??¡¤?Twitter:?
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I own the Afedri SDR Net, SDRplay RSP Duo and Airspy HF+. I've tested all of these units thoroughly on an 80m passive loop, active loops, and tuned loops on LF~HF. For me the Afedri wins, but not by much (a couple of dB or so in s/n ratio). As for the RSP Duo consideration has to be given to the fact that it is an ultra wideband receiver. However, if used wisely (correct adjustment of the front end in software, or an external attenuator when conditions dictate), It is very capable on LF~HF (Splitting hairs on HF, not as good on LF), and its diversity reception feature has proved useful on many occasions. In fact given it's coverage, versatility and price, I'd argue it is a must-buy for anyone who's not solely interested in LF and MW. My Airspy HF+ is out on semi-permanent loan, for me its redundant.
I started out in PC connected SDR's building SoftRock kits, I've learned they all behave differently, and work is always required to eliminate locally generated noise and ground loops. I often wonder if some owners fully understand how important this is to thoroughly testing the performance of an SDR.
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Re: Capacitance meter with 2 TLC555 timers 0.1pF resolution
You can zoom in, it is very large. Same with all the pictures.
--
Steve Greenfield AE7HD
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Re: Capacitance meter with 2 TLC555 timers 0.1pF resolution
Thanks very much for sharing. Can the second schematic be made
larger so it can be better read?
Steve AA7U
On 1/5/2022 5:11 PM, Steven Greenfield
AE7HD via groups.io wrote:
toggle quoted message
Show quoted text
I built a fair number of these, starting in the '70s shortly after
Radio Shack started carrying the NE555 timer. I usually used the
Micronta 50uA panel meters for the readout. I'd watch for project
boxes on sale in Radio Shack and surplus electronics stores. I
used the dry transfer rub-on lettering, or sometimes I'd make the
front panel out of PCB and etch lettering into it.
?
I didn't set out to sell them. I'd show them to someone,
they'd ask where I bought it, call me a liar for saying I
designed and built it... then ask me how much to buy it from me.
So I'd sell it and build another.
?
In the mid '80s, I started building them to use a DMM as the
display. On the lowest scale, 1mV = 1pF, so for a meter on
200.0mV, 0.1pF resolution. I built an ugly prototype with parts
I had on hand, then started building nicer ones and selling
them.
?
I still have the ugly prototype, and a few years ago I found
the notebook with the schematic for it. Hackaday.io is having a
555 timer contest, I thought I might as well document this there
and enter it.
?
I found a resistor or two in the ugly prototype has
apparently drifted, or the selector switch may be dirty. So I'll
be cleaning it up and may be replacing some resistors, then I
think I will make a surface mount version and do it as a kit for
our local makerspace. I think I'll add traces so it can be built
for several purposes, including liquid level, touch switch,
remote sensing on 2 wires, etc.
?
Anyway, here it is if you are interested:
?
?
I thought it might be interesting to see if I can push this
to be stable enough to be useful to a 0.01pF/10fF resolution.
Without a microcontroller. For that, I think I'll add a CD4060
with crystal.
I drew a clearer schematic and a block diagram with explanation.
I welcome comnents.
?
Steve Greenfield AE7HD
?
--
Steve Greenfield AE7HD
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Locked
Capacitance meter with 2 TLC555 timers 0.1pF resolution
I built a fair number of these, starting in the '70s shortly after Radio Shack started carrying the NE555 timer. I usually used the Micronta 50uA panel meters for the readout. I'd watch for project boxes on sale in Radio Shack and surplus electronics stores. I used the dry transfer rub-on lettering, or sometimes I'd make the front panel out of PCB and etch lettering into it.
?
I didn't set out to sell them. I'd show them to someone, they'd ask where I bought it, call me a liar for saying I designed and built it... then ask me how much to buy it from me. So I'd sell it and build another.
?
In the mid '80s, I started building them to use a DMM as the display. On the lowest scale, 1mV = 1pF, so for a meter on 200.0mV, 0.1pF resolution. I built an ugly prototype with parts I had on hand, then started building nicer ones and selling them.
?
I still have the ugly prototype, and a few years ago I found the notebook with the schematic for it. Hackaday.io is having a 555 timer contest, I thought I might as well document this there and enter it.
?
I found a resistor or two in the ugly prototype has apparently drifted, or the selector switch may be dirty. So I'll be cleaning it up and may be replacing some resistors, then I think I will make a surface mount version and do it as a kit for our local makerspace. I think I'll add traces so it can be built for several purposes, including liquid level, touch switch, remote sensing on 2 wires, etc.
?
Anyway, here it is if you are interested:
?
https://hackaday.io/project/183405-dual-tlc555-capacitance-meter-01pf-resolution
?
I thought it might be interesting to see if I can push this to be stable enough to be useful to a 0.01pF/10fF resolution. Without a microcontroller. For that, I think I'll add a CD4060 with crystal.
I drew a clearer schematic and a block diagram with explanation. I welcome comnents.
?
Steve Greenfield AE7HD http://www.linkedin.com/in/stevenjgreenfield
?
--
Steve Greenfield AE7HD
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Paul,
?
The older ALA100s have lower gain and a higher input impedance compared to
the more resent offerings.
Therefore, I would suggest that your don¡¯t alter the loop you already
have.
?
73
?
Andrew
?
?
?
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From: Paul
MW0CDO
Sent: Wednesday, January 5, 2022 12:05 PM
Subject: [loopantennas] Wellbrook ALA100
?
Hello Andrew,
I have an elderly ALA100 amplifier & power injector.
It is working very well, but I was wondering what recommendations you might
have regarding the actual loop.
I currently have a vertical rectangle approx 25ft horizontally & 15ft
vertical with the bottom of the loop around 8ft AGL all supported on 2
fibreglass poles as far from housing as possible.
Any suggestions for me? I don¡¯t have any specific problem but wondered
whether a different loop size or format might bring benefits?
My naim
interests are MWDX, amateur bands reception from 160-10m & generally tuning
around between 10KHz & 30MHz.
My environment is unusual, sandwiched
between the M4 motorway / Welsh hills & the steelworks in Port Talbot about
800 yards from the Bristol Channel.
As it stands, it works very well for
me.
Any input welcomed!
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Locked
Re: Band pass filter recommendation
Would suggest Tonne software ELSIE to design crossover filter. Tonne software is exceptionally good.
73, Alan G8LCO
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Hello Andrew,
I have an elderly ALA100 amplifier & power injector.?
It is working very well, but I was wondering what recommendations you might have regarding the actual loop.?
I currently have a vertical rectangle approx 25ft horizontally & 15ft vertical with the bottom of the loop around 8ft AGL all supported on 2 fibreglass poles as far from housing as possible.?
Any suggestions for me? I don¡¯t have any specific problem but wondered whether a different loop size or format might bring benefits?
My naim interests are MWDX, amateur bands reception from 160-10m & generally tuning around between 10KHz & 30MHz.
My environment is unusual, sandwiched between the M4 motorway / Welsh hills & the steelworks in Port Talbot about 800 yards from the Bristol Channel.
As it stands, it works very well for me.
Any input welcomed!
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Locked
Re: Measuring noise level during car drive
On Tue, Jan 4, 2022 at 07:34 PM, §é§Ñ§Ó§Õ§Ñ§â §Ý§Ö§Ó§Ü§à§Ó wrote:
I was not aware about your postings on this topic. Excuse me for that, you are ahead of me in technology.
Hi Chavdar, No need to apologise, my webpage regarding the system is quite well hidden, and I haven't done any further work on it for several years. At the time I was trying to develop a low cost system around an RTL dongle that could be used to map VDSL noise by driving around the affected area. The intention was to encourage local radio clubs to have a system that could be borrowed by members, in order to locate VDSL hot spots, and then to be able to provide evidence to the UK telecoms regulator in order to try and get the problem resolved.? However there wasn't as much interest as I'd hoped, and the available software wasn't that easy to use. So in the end the project got put on hold, and in the meantime a new set of other interference sources, such as Solar PV and Car chargers have become more problematic. I'm still hopeful that one of the SDR software authors will at some stage add the ability to use GPS co-ordinates. But at the moment Winradio is the only company I know of who are offering software a price that is unfortunately still not quite affordable to the average hobby user. Good luck with your experiments, and thanks for all of the really useful and detailed information on your website. I have found your recent index of articles to be particularly helpful in finding items of interest. Regards, Martin
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Re: Band pass filter recommendation
On Wed, Jan 5, 2022 at 04:00 AM, Tom Seeger wrote:
You mean anything below 14 MHz?comes from the loop and anything above 14MHz?comes from the dipole? I think you would have to make your own.
The device you require is called a diplexer. Tonne Software provide a free design tool. Don't worry about making it too complicated. Two coils and two capacitors should be adequate for your purpose, but there will be some interaction between the two antennas around the cross over frequency. So I'd try to make this cross over away from any frequencies of particular interest, and chose a bit of the spectrum that is relatively quiet instead. Send me a PM if you need any help with the design and construction. Regards, Martin
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Re: New Chameleon CHA RXL receive loop antenna
Hi Steve,
Maybe you could possibly help me out. I?just purchased the Chameleon RXL receive loop. And now I wish I had found this thread before doing so. I¡¯m very new to these antennas. I currently use a Ciro Mazzoni Baby Loop antenna for transmitting and receiving. And I wanted to have a receive antenna that didn¡¯t have such a narrow bandwidth. So I opted for this. The RXL.
The problem that I am having is an extremely high noise floor with the RXL. Well over an S9. It completely blankets the lighter signals. I think the guy from Chameleon said it was a really hot signal. So my question to you is, Can I put something inline like some sort of receive filter to attenuate some of that noise??Or would it require a different preamp??Like I said, I really don¡¯t know much about these loops.?
But what I do know is that when I rotate the loop, the really hot part of the signal goes away on the scope but I still have a noise floor of an S7 to S8. It¡¯s louder than any interference that I get on my Ciro Mazzoni mla or my portable vertical antenna.?
I¡¯m hoping you could possibly help me identify what¡¯s going on with this loop. Hopefully you will have some sort of idea as to what I¡¯m up against. Let me know if you need any other details.?
73,
Phil Schuyler, ?KN6NNO?
?
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Re: Band pass filter recommendation
You mean anything below 14 MHz?comes from the loop and anything above 14MHz?comes from the dipole? I think you would have to make your own. You will need a lowpass filter on the RX side of your loops' bias-t and a high pass filter from the dipole. Both will feed a combiner, who's output feeds the Kiwi. Here is a link to a good filter design tool:
Here is a link for DIY splitter/combiners:
73 Tom
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Band pass filter recommendation
Is there a good band pass filter you would recommend that I could have anything below 14Mhz goes to loop and anything above goes to my Dipole?? (For KIWISDR receiver)
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Re: Measuring noise level during car drive
Martin and Chavdar,
I have had similar ideas but more focused on the emissions from the vehicle.
Some hybrids make VHF almost unusable. Others have strong signals on the HF bands.
Not quite there yet but SDR, waterfall, gamer recorder and antenna.
Loop in the cabin? Active antenna on the boot? Tuned whip?
Will look at GPS mapping.
Thoughts?
Andrew VK5CV
?
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: §é§Ñ§Ó§Õ§Ñ§â §Ý§Ö§Ó§Ü§à§Ó
Sent: Wednesday, 5 January 2022 6:05 AM
To: [email protected]
Subject: Re: [loopantennas] Measuring noise level during car drive
?
Hi Martin,
I was not aware about your postings on this topic. Excuse me for that, you are ahead of me in technology. I read them with great interest. I will add them to the links in my article. Yes GPS sync is a need if a "noise" map? must be drawn but I have made these
recordings just of curiosity to see? what is going on with the man made noise in my county. The most important result was that I compared? the minimal recorded noise with the noise at my house - so now I know "where I am" . The VDSL systems are very rarely
used here.- most common are LAN cables and cable TV. The telephone lines do not exist here any more - everything is GSM.? I choose 3.5 MHz as a center frequency? because in semi-urban areas I have noticed that there the noise level has a peak (between 2 -
4 MHz) I do not have an explanation for that.? It will be interesting? for someone else to make similar recordings in order to compare the noise pollution.? We do not need? precise calibration - the level of the noise in quiet places is a good reference point.
The merit of pollution will be? Nc/Nq?? where Nc is the current noise level? and? Nq is a quiet place noise level measured in the same date and time(approximately) . (or Nc-Nq in dBm). This can be done by car (or bicycle? : -)
Chavdar lz1aq
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Re: Measuring noise level during car drive
Hi Martin,
I was not aware about your postings on this topic. Excuse me for that, you are ahead of me in technology. I read them with great interest. I will add them to the links in my article. Yes GPS sync is a need if a "noise" map? must be drawn but I have made these recordings just of curiosity to see? what is going on with the man made noise in my county. The most important result was that I compared? the minimal recorded noise with the noise at my house - so now I know "where I am" . The VDSL systems are very rarely used here.- most common are LAN cables and cable TV. The telephone lines do not exist here any more - everything is GSM.? I choose 3.5 MHz as a center frequency? because in semi-urban areas I have noticed that there the noise level has a peak (between 2 - 4 MHz) I do not have an explanation for that.? It will be interesting? for someone else to make similar recordings in order to compare the noise pollution.? We do not need? precise calibration - the level of the noise in quiet places is a good reference point. The merit of pollution will be? Nc/Nq?? where Nc is the current noise level? and? Nq is a quiet place noise level measured in the same date and time(approximately) . (or Nc-Nq in dBm). This can be done by car (or bicycle? : -)
Chavdar lz1aq
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Re: Measuring noise level during car drive
On Tue, Jan 4, 2022 at 05:30 PM, §é§Ñ§Ó§Õ§Ñ§â §Ý§Ö§Ó§Ü§à§Ó wrote:
I have made some measurements of the ambient electromagnetic noise during car drive.
Hi Chavdar, A very interesting post, and something I would like to be able to do better. If you could capture GPS co-ordinates you could produce a heat map, something like this on one of my webpages. I used a mapping add-on in Excel to combine the data and overlay it on the satellite map images. I've been trying to persuade various popular SDR software authors to include the option to add GPS derived co-ordinates to recorded signal strength logs in order to make this task easier, but no luck so far. Good luck with your work. Martin
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Measuring noise level during car drive
I have made some measurements of the ambient electromagnetic noise during car drive.
?Happy New Year to everybody. ?
Chavdar LZ1AQ
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While I didn't find an all-inclusive list, a simple www search yielded some useful information:
That's enough.? You should do your own web search as there is a plethora of information there on the subject.
-- Dave - W?LEV
Just Let Darwin Work
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May I suggest also the Elad S2 ?
I have both the Perseus and the Elad S2, and have performed A/B comparisons, and to my ears they perform similarly.
The Elad S2 is quite sensitive down to 10 kHz. I have used it last Christmas Eve to receive the annual SAQ transmission, and you can see the results here :
And the Elad S2 is about half the price of the Perseus....
73? Alberto? I2PHD
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Steven Greenfield AE7HD
Alberto I2PHD