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Locked Re: What is your preferred antenna for SWL'ing on a balcony.

Paul Egan
 

I built a moebius loop from a couple of 1.2m pieces of RG-8X that I had lying around ( a bit bigger than it should be). I attached a 1:1 balun intended for a dipole also that I had lying around. It's not perfect but it does hear quite well from 6 to 8 Mhz. and I can hear MW stations for the first time on this rtl-sdr v3. Need to look at other frequencies this evening but I'd say it's a pretty good starting point.

Added a cheap aliexpress LNA at the feedpoint and got too much MW + FM signal, as Tom predicted. So I removed it.

I'm tracking aircraft using PC-HFDL and Google Earth (New York on 6661 khz.). There are more on the screen than I've seen before. Some are arriving and departing in NYC and Chicago which I had never noticed before.
40m ham band is very active.

I agree that I need to upgrade the SDR and intend to soon but it's good to see what this little dongle can do.

Thanks again for everyone's input.
73,
Paul VA3ZC
Locked Re: Best SDR Receivers

 

Honestly, from everything?I've read here and other forums, for LF, MF and HF you can either choose the AirSpy Discovery HF+ or Perseus.

The only practical diference is seen if you decide adopting techniques and workflow of hard core MW DX folks:

- Perseus allows you to record slices of up to 2MHz, while AirSpy DHF+ can only record slices of 900 KHz.

- Perseus lets you to use Jaguar SDR software, which was specifically tailored for MW DXing and became the standard in the hobby.

- Perseus has better/more numerous traditional band-pass filters. AirSpy DHF+ has fewer filters, but its car-stereo IC (ST Microeletronics?STA709)?uses ?'polyphase mixer' for improve performance*

AHF+ has some advantages on its own:

- powered directly from the USB port (Perseus needs a separate power supply)

- Coverage between 61 and 260MHz, providing a very decent VHF and Broadcast FM receiver (Perseus goes up to 40MHz, 88-108MHz coverage possible if you buy their downconverter)

pu3hag

*?

On Mon, Jan 3, 2022, 20:33 Everett N4CY via <everettsharp=[email protected]> wrote:
Hi Bob,

How did you add the picture and contact info to your email?

Everett N4CY




On Monday, January 3, 2022, 5:05 PM, Bob Willey K3RLW <bobwilley@...> wrote:

Does anyone have a chart comparing features/price, like sensitivity and other special feataures for the uninformed, so not everyone has to make all the mistakes.
Thanks.



photo
Bob Willey
K3RLW

(410) 251-8960 | K3RLW@...

5161 Ocean Gateway, Trappe Maryland 21673-2023 USA

On Mon, Jan 3, 2022 at 3:55 PM Chris Smolinski <csmolinski@...> wrote:
The AFEDRI SDRs are worth considering as well. Not quite the performance of my RF Space netSDR, but still respectable.

Chris Smolinski, W3HFU
Black Cat Systems
Westminster, MD USA







> On Jan 3, 2022, at 3:50 PM, W0LEV <davearea51a@...> wrote:
>
> Yes, front end overload is a major shortcoming of the SDRPlays.? Not so much so for the AirSpy products.? Yes, the Persus is outstanding and I wish I had one, but not in the cards on a retirement "salary".? Anyone want to contribute one to me??????
>
> Dave - W?LEV
>
> On Mon, Jan 3, 2022 at 8:27 PM Everett N4CY via <everettsharp=[email protected]> wrote:
> If you are going to buy a SDR, buy either a Pereus, or a RFSpace CloudSDR. I have both and they are top of the line. I have had several AirSpys and SDRPlays. The AirSPY is okay, but skips band coverage and the SRPPlay DUO has a very poor receiver. The SDRPlay rspDX is better but the front end overloads.
>?
> Everett N4CY
>
> In a message dated 1/3/2022 1:51:18 PM Central Standard Time, davearea51a@... writes:
>?
> The AirSpy is a far superior product to the SDRPlay.? I have both and several iterations of the AirSpys including the HF+ Discovery.? The SDRPlay sits on the shelf gathering dust.? Spend a bit more and go with the AirSpy products.
>?
> Dave - W?LEV
>
> On Mon, Jan 3, 2022 at 6:58 PM Tom Seeger <thomas.b.seeger@...> wrote:
> Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
> 73 Tom
>?
>?
>
>
> --
> Dave - W?LEV
> Just Let Darwin Work
>
>
>
>
> --
> Dave - W?LEV
> Just Let Darwin Work
>
>






Locked Re: Good Vibrations? / locking compounds

 

I have used my daughters finger nail polish as thread locker. Yes it does contain acetone but if used sparingly and on the end of the screw and nut, should not cause a plastic meltdown event. It worked so well, I now have a nail polish collection of my own!

73,
Kevin
kc6pob
On Sunday, January 2, 2022, 10:12:29 PM PST, Fred Moore <n40cla@...> wrote:


Good?morning all.??

I have been following all the comments about vibrations on the antenna causing mounting hardware to loosen.? I have used the following type of hardware for years at commercial sites and can't remember where we have had any hardware loosen up for whatever?reasons.? The attached link below uses one nut and one split ring washer at every point where any tightening is to happen for mounting.? All the big boys, 2 way communication, cell site antennas etc use this type of hardware and once it is up it is never touched again until it has to come down or be moved.? No criticisms intended, just my opinion.



Fred - N4CLA

On Sun, Jan 2, 2022 at 7:45 PM Leigh Turner <invertech1@...> wrote:
Good fit-for-purpose cautionary advice here Alan....

Leigh
VK5LT

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Alan
Sent: Monday, 3 January 2022 10:50 AM
To: [email protected]
Subject: Re: [loopantennas] Good Vibrations?

I would NEVER USE LOCKING COMPOUND ON PLASTICS. Many locking compounds can destroy plastic parts over time, they are formulated for locking metal part not plastics.? Same goes for some greases. One former employee used locking compound on plastic nuts, cost ?35,000 to replace the parts.

One Italian manufacturer used a grease to ease driving screws into plastic pillars. After a year the pillars disintegrated and cost the manufacturer a lot of money.

73, Alan G8LCO.
Locked Re: Best SDR Receivers

 

Does anyone have a chart comparing features/price, like sensitivity and other special feataures for the uninformed, so not everyone has to make all the mistakes.
Thanks.



photo
Bob Willey
K3RLW

(410) 251-8960 | K3RLW@...

5161 Ocean Gateway, Trappe Maryland 21673-2023 USA


On Mon, Jan 3, 2022 at 3:55 PM Chris Smolinski <csmolinski@...> wrote:
The AFEDRI SDRs are worth considering as well. Not quite the performance of my RF Space netSDR, but still respectable.

Chris Smolinski, W3HFU
Black Cat Systems
Westminster, MD USA







> On Jan 3, 2022, at 3:50 PM, W0LEV <davearea51a@...> wrote:
>
> Yes, front end overload is a major shortcoming of the SDRPlays.? Not so much so for the AirSpy products.? Yes, the Persus is outstanding and I wish I had one, but not in the cards on a retirement "salary".? Anyone want to contribute one to me??????
>
> Dave - W?LEV
>
> On Mon, Jan 3, 2022 at 8:27 PM Everett N4CY via <everettsharp=[email protected]> wrote:
> If you are going to buy a SDR, buy either a Pereus, or a RFSpace CloudSDR. I have both and they are top of the line. I have had several AirSpys and SDRPlays. The AirSPY is okay, but skips band coverage and the SRPPlay DUO has a very poor receiver. The SDRPlay rspDX is better but the front end overloads.
>?
> Everett N4CY
>
> In a message dated 1/3/2022 1:51:18 PM Central Standard Time, davearea51a@... writes:
>?
> The AirSpy is a far superior product to the SDRPlay.? I have both and several iterations of the AirSpys including the HF+ Discovery.? The SDRPlay sits on the shelf gathering dust.? Spend a bit more and go with the AirSpy products.
>?
> Dave - W?LEV
>
> On Mon, Jan 3, 2022 at 6:58 PM Tom Seeger <thomas.b.seeger@...> wrote:
> Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
> 73 Tom
>?
>?
>
>
> --
> Dave - W?LEV
> Just Let Darwin Work
>
>
>
>
> --
> Dave - W?LEV
> Just Let Darwin Work
>
>






Locked Re: Best SDR Receivers

 

The AFEDRI SDRs are worth considering as well. Not quite the performance of my RF Space netSDR, but still respectable.

Chris Smolinski, W3HFU
Black Cat Systems
Westminster, MD USA

On Jan 3, 2022, at 3:50 PM, W0LEV <davearea51a@...> wrote:

Yes, front end overload is a major shortcoming of the SDRPlays. Not so much so for the AirSpy products. Yes, the Persus is outstanding and I wish I had one, but not in the cards on a retirement "salary". Anyone want to contribute one to me??????

Dave - W?LEV

On Mon, Jan 3, 2022 at 8:27 PM Everett N4CY via groups.io <everettsharp@...> wrote:
If you are going to buy a SDR, buy either a Pereus, or a RFSpace CloudSDR. I have both and they are top of the line. I have had several AirSpys and SDRPlays. The AirSPY is okay, but skips band coverage and the SRPPlay DUO has a very poor receiver. The SDRPlay rspDX is better but the front end overloads.

Everett N4CY

In a message dated 1/3/2022 1:51:18 PM Central Standard Time, davearea51a@... writes:

The AirSpy is a far superior product to the SDRPlay. I have both and several iterations of the AirSpys including the HF+ Discovery. The SDRPlay sits on the shelf gathering dust. Spend a bit more and go with the AirSpy products.

Dave - W?LEV

On Mon, Jan 3, 2022 at 6:58 PM Tom Seeger <thomas.b.seeger@...> wrote:
Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
73 Tom




--
Dave - W?LEV
Just Let Darwin Work




--
Dave - W?LEV
Just Let Darwin Work
Locked Re: Best SDR Receivers

 

Yes, front end overload is a major shortcoming of the SDRPlays.? Not so much so for the AirSpy products.? Yes, the Persus is outstanding and I wish I had one, but not in the cards on a retirement "salary".? Anyone want to contribute one to me??????

Dave - W?LEV


On Mon, Jan 3, 2022 at 8:27 PM Everett N4CY via <everettsharp=[email protected]> wrote:
If you are going to buy a SDR, buy either a Pereus, or a RFSpace CloudSDR. I have both and they are top of the line. I have had several AirSpys and SDRPlays. The AirSPY is okay, but skips band coverage and the SRPPlay DUO has a very poor receiver. The SDRPlay rspDX is better but the front end overloads.
?
Everett N4CY

In a message dated 1/3/2022 1:51:18 PM Central Standard Time, davearea51a@... writes:
?
The AirSpy is a far superior product to the SDRPlay.? I have both and several iterations of the AirSpys including the HF+ Discovery.? The SDRPlay sits on the shelf gathering dust.? Spend a bit more and go with the AirSpy products.
?
Dave - W?LEV

On Mon, Jan 3, 2022 at 6:58 PM Tom Seeger <thomas.b.seeger@...> wrote:
Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
73 Tom

?

?



--
Dave - W?LEV
Just Let Darwin Work



--
Dave - W?LEV
Just Let Darwin Work
Locked Re: Best SDR Receivers

 

If you are going to buy a SDR, buy either a Pereus, or a RFSpace CloudSDR. I have both and they are top of the line. I have had several AirSpys and SDRPlays. The AirSPY is okay, but skips band coverage and the SRPPlay DUO has a very poor receiver. The SDRPlay rspDX is better but the front end overloads.
?
Everett N4CY

In a message dated 1/3/2022 1:51:18 PM Central Standard Time, davearea51a@... writes:
?

The AirSpy is a far superior product to the SDRPlay.? I have both and several iterations of the AirSpys including the HF+ Discovery.? The SDRPlay sits on the shelf gathering dust.? Spend a bit more and go with the AirSpy products.
?
Dave - W?LEV

On Mon, Jan 3, 2022 at 6:58 PM Tom Seeger <thomas.b.seeger@...> wrote:
Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
73 Tom

?

?



--
Dave - W?LEV
Just Let Darwin Work
Locked Re: Is this Wellbrook wide aperture loop faulty?

 

Hello Tom,

Monday, January 3, 2022

This TS-590S that I have had for donkey's years has been great on LF, both RX and TX, but the start of its ills came when I managed to transmit a kilowatt of RF INTO th RX port. I fixed it but it has since had other issues and now has a fade on RX problem that seems heat related. It's time to put it out to pasture and either buy a new one or something similar. I use a Red Pitaya and pre amp and the Kiwi plus some Softrocks for RX as well as the 590, but only the Red Piataya could be made to TX as well.


Best regards,
Chris mailto:chris@...


TCG> Sounds like you are making great progress Chris.

TCG> I doubt that a new TCVR will make much of a difference. Most of
TCG> them will have filtering to reduce sensitivity at LF/MF. This is
TCG> to reduce the likelihood of problems at HF, like spurious breakthrough etc.
TCG> Is there any chance you could borrow a modern rig and prove me wrong?

TCG> Tom G6PZZ

TCG> -----Original Message-----
TCG> From: [email protected] <[email protected]> On Behalf Of Chris Wilson
TCG> Sent: 03 January 2022 09:34
TCG> To: Alan <[email protected]>
TCG> Subject: Re: [loopantennas] Is this Wellbrook wide aperture loop faulty?

TCG> Hello Alan, Martin et al,

TCG> Saturday, January 1, 2022

TCG> People must be getting bored with my saga by now, so I will
TCG> keep it as short as I can. Basically, yesterday lent me the
TCG> opportunity to do some more tests. Running the injector box off a
TCG> 12V accumulator made zero noticeable difference. Running the KIwi
TCG> as well, off my mobile phone 5V power pack made a minute
TCG> difference to overall noise. Disconnecting the coax to the
TCG> antenna at the injector box still left some strong signals.
TCG> Wrapping about 10 turns of the coax out to the loop around a BIG
TCG> ferrite ring (I have the spec but can't recall it off hand) made a noticeable difference.

TCG> Then I had the idea to wrap the short (2 foot or so) of coax
TCG> from the injector box to the Kiwi as many turns as possible
TCG> around a similar ferrite ring. I think I got about 5 or six turns
TCG> on, the BNC plug limited this. Now THAT made a big difference!

TCG> I am pretty pleased to have persevered and enormously grateful to those who stuck with me.

TCG> Downside is MF / LF amateur digital performance has markedly
TCG> deteriorated. Is it the smaller circumference of the new loop?
TCG> The 30 to 35 or so degrees rotation of the loop form its
TCG> orientation looking down from the sky (plan view)? Originally the
TCG> loop in plan view ran almost east to west, it's now skewed about
TCG> 35 degrees or so anti clockwise and a bit lower overall....


TCG> Testing has been made a bit problematic as my TS-580S which has
TCG> had a hard, no, very hard life, has started to lose sensitivity
TCG> and sometimes goes totally dead on receive. It seems heat
TCG> related, but it's years old and had one incident where I managed
TCG> to shove a kilowatt of LF 137 kHz up the receive antenna port.

TCG> Needless to say it didn't like it and I amazed and astounded
TCG> myself by managing to repair it with my scope and a sig gen. More
TCG> good luck, strong coffee and a good light source, plus a huge
TCG> taped together print out of the schematic.

TCG> I think I might treat myself to a newer (if still secondhand)
TCG> rig soon. As an aside what modern transceivers hear well at LF
TCG> and MF and will TX a milliwatt or so on LF and MF to act as an
TCG> exciter, anyone here any experience of anything suitable or
TCG> should I just get a newer TS-590?

TCG> Critical comments welcome:

TCG>

TCG> Thanks again everyone.

TCG> Best regards,
TCG> Chris mailto:chris@...


A>> Martin

A>> As Andrew said shorting the input is not a good idea and will not do
A>> what you think it will. Leaving the terminals open will but you need
A>> to disconnect both terminals. The amplifier is a Zwischenbasis type,
A>> as you have plotted in the past the input reacts to the signal source
A>> impedance. This form of noiseless feedback is the complement to the
A>> Norton Amplifier where the output impedance is a transformed version
A>> of the input impedance, here the output impedance hardly matters but
A>> you get to optimise the matching to the source over a much wider
A>> range than a conventional "dumb" input , it is NOT a virtual earth
A>> amplifier in the normal sense ( which also goes nuts with a shorted
A>> input !) but a much cleverer configuration due to Cantz from 1953.

A>> However before disconnecting the loop I would remove the power to
A>> the injector then disconnect the coax to the injector. That would
A>> show what is leaking into to the coax and then what remains after the
A>> coax is removed. It seems futile to disconnect the loop when you can
A>> just power it down.

A>> I used a naked ALA100LN until recently, it works very well from LF to
A>> HF and beyond. The IMD performance is outstanding six miles from
A>> Brookman's Park. I now use a new arrangement that drops BP signals
A>> an additional 30dB. I spot to PSK reporter from a tiny urban back
A>> garden, Don't do too bad for an antenna 3m high surrounded by
A>> switchers although BT has blocked 30m very effectively.

A>> 73, Alan G8LCO.















TCG>
Locked Re: What is your preferred antenna for SWL'ing on a balcony.

 

The AirSpy is a far superior product to the SDRPlay.? I have both and several iterations of the AirSpys including the HF+ Discovery.? The SDRPlay sits on the shelf gathering dust.? Spend a bit more and go with the AirSpy products.

Dave - W?LEV


On Mon, Jan 3, 2022 at 6:58 PM Tom Seeger <thomas.b.seeger@...> wrote:
Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
73 Tom



--
Dave - W?LEV
Just Let Darwin Work
Locked Re: What is your preferred antenna for SWL'ing on a balcony.

 

Hi Paul. I'd like to save you some grief. I've used the rtl-sdr v3. So I speak from experience. The Youloop was designed to be used with the Airspy HF+ which has very high sensitivity. The rtl-sdr v3 has quite poor sensitivity and using a youloop without an amplifier will leave you disappointed. Since you live in a big city on the 10th floor, just adding a broadband RF amplifier will most likely swamp the rtl-sdr v3 with FM and probably AM signals too. So plan on building or buying a lowpass and maybe a high pass filter as well. This is why I recommended the MLA-30. It contains the filters and an adjustable attenuator. Alternatively as mentioned you might want to spend your dollars on a better SDR that has good built-in bandpass filters like the Airspy or SDRplay.
73 Tom
Locked Re: Is this Wellbrook wide aperture loop faulty?

 

Hi Tom

I think most/all switch the below mw ( hpf) filter in and out depending upon frequency.. damn sure mine does when tune below 1700khz..above in, below out.otherwise it would be deaf below 1700..

Simon
Locked Re: Is this Wellbrook wide aperture loop faulty?

 

Sounds like you are making great progress Chris.

I doubt that a new TCVR will make much of a difference. Most of them will have filtering to reduce sensitivity at LF/MF. This is to reduce the likelihood of problems at HF, like spurious breakthrough etc.
Is there any chance you could borrow a modern rig and prove me wrong?

Tom G6PZZ

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Chris Wilson
Sent: 03 January 2022 09:34
To: Alan <[email protected]>
Subject: Re: [loopantennas] Is this Wellbrook wide aperture loop faulty?

Hello Alan, Martin et al,

Saturday, January 1, 2022

People must be getting bored with my saga by now, so I will keep it as short as I can. Basically, yesterday lent me the opportunity to do some more tests. Running the injector box off a 12V accumulator made zero noticeable difference. Running the KIwi as well, off my mobile phone 5V power pack made a minute difference to overall noise. Disconnecting the coax to the antenna at the injector box still left some strong signals. Wrapping about 10 turns of the coax out to the loop around a BIG ferrite ring (I have the spec but can't recall it off hand) made a noticeable difference.

Then I had the idea to wrap the short (2 foot or so) of coax from the injector box to the Kiwi as many turns as possible around a similar ferrite ring. I think I got about 5 or six turns on, the BNC plug limited this. Now THAT made a big difference!

I am pretty pleased to have persevered and enormously grateful to those who stuck with me.

Downside is MF / LF amateur digital performance has markedly deteriorated. Is it the smaller circumference of the new loop? The 30 to 35 or so degrees rotation of the loop form its orientation looking down from the sky (plan view)? Originally the loop in plan view ran almost east to west, it's now skewed about 35 degrees or so anti clockwise and a bit lower overall....


Testing has been made a bit problematic as my TS-580S which has had a hard, no, very hard life, has started to lose sensitivity and sometimes goes totally dead on receive. It seems heat related, but it's years old and had one incident where I managed to shove a kilowatt of LF 137 kHz up the receive antenna port.

Needless to say it didn't like it and I amazed and astounded myself by managing to repair it with my scope and a sig gen. More good luck, strong coffee and a good light source, plus a huge taped together print out of the schematic.

I think I might treat myself to a newer (if still secondhand) rig soon. As an aside what modern transceivers hear well at LF and MF and will TX a milliwatt or so on LF and MF to act as an exciter, anyone here any experience of anything suitable or should I just get a newer TS-590?

Critical comments welcome:



Thanks again everyone.

Best regards,
Chris mailto:chris@...


A> Martin

A> As Andrew said shorting the input is not a good idea and will not do
A> what you think it will. Leaving the terminals open will but you need
A> to disconnect both terminals. The amplifier is a Zwischenbasis type,
A> as you have plotted in the past the input reacts to the signal source
A> impedance. This form of noiseless feedback is the complement to the
A> Norton Amplifier where the output impedance is a transformed version
A> of the input impedance, here the output impedance hardly matters but
A> you get to optimise the matching to the source over a much wider
A> range than a conventional "dumb" input , it is NOT a virtual earth
A> amplifier in the normal sense ( which also goes nuts with a shorted
A> input !) but a much cleverer configuration due to Cantz from 1953.

A> However before disconnecting the loop I would remove the power to
A> the injector then disconnect the coax to the injector. That would
A> show what is leaking into to the coax and then what remains after the
A> coax is removed. It seems futile to disconnect the loop when you can
A> just power it down.

A> I used a naked ALA100LN until recently, it works very well from LF to
A> HF and beyond. The IMD performance is outstanding six miles from
A> Brookman's Park. I now use a new arrangement that drops BP signals
A> an additional 30dB. I spot to PSK reporter from a tiny urban back
A> garden, Don't do too bad for an antenna 3m high surrounded by
A> switchers although BT has blocked 30m very effectively.

A> 73, Alan G8LCO.





A>
Locked Re: Good Vibrations?

 

All noted Andrew, the installation has been a valuable part of my listening arsenal and is weathering well and continues to give a good account of itself.
Locked Re: What is your preferred antenna for SWL'ing on a balcony.

 

Happy New Year. My favorite at the moment?is the LZ1AQ active amplifier?configured with two orthogonal loops. I have the you loop but have not had the chance to test it.?

Mike
AB4KJ

On Sun, Jan 2, 2022 at 5:25 PM Paul Egan <paul@...> wrote:
I have a 10th floor balcony and would like a no tune solution for an rtl-sdr v3 with an upconverter.

I've tried a miniwhip from aliexpress. It was pretty deaf.

The youloop looks interesting but I think it needs a more sensitive SDR and using an LNA with the rtl-sdr v3 only elevates the noise from what I understand.

I have a homebrew magnetic loop for transmitting between 17m and 40m but tuning is cumbersome and I would like to receive below 7Mhz.

So what would you install to get a decent signal from 0.5 to 30Mhz? Some sort of passive loop?

Thanks.



.

Locked Re: Good Vibrations?

 

¿ªÔÆÌåÓý

A rubber gasket is part of the installation kit for the 1m loops. This is to prevent the threaded metal dome from scuffing the plastic loop box and also it should cushion some of the mechanical stress on the Dome cover. Hence, the fixing nuts should not be over tightened so as the compress the casket too much. However, as already suggested; a further nut can be use as locking nut.
?
Kind regards
?
Andrew Ikin
Locked Re: What is your preferred antenna for SWL'ing on a balcony.

 

will give it a go soon (I hope)
Many thanks and have a great 2022.

// pedro andrade


On Mon, Jan 3, 2022 at 10:51 AM Ian Brooks <ian.brooks4073@...> wrote:

Try this link from Martin, G8JNJ: or this one:

The diagram is the same as the one that appeared in the airspy group in 2017. The BN73-302 core is smaller than the BN73-202 core, but the -202 is probably easier to wind. Others have had good results with various toroid cores and ones salvaged from defunct USB cables or 75 to 300-ohm baluns. Room for some experimenting here. I actually used 75-ohm RG59-Mini cable because I had a lot of it, but it doesn't appear to be critical.

Ian.

On 03/01/2022 10:10, DX Pedro wrote:
mind sharing some links/diagrams for dummies like myself?
many thanks.
// pedro andrade


On Mon, Jan 3, 2022 at 1:53 AM Ian Brooks <ian.brooks4073@...> wrote:

The Mini-Whip antennas do not function very well indoors and probably not very well on a balcony. If you're into a bit of home construction, a YouLoop or Moebius antenna is definitely worth a try and is very cheap to build yourself as it is basically two short lengths of coax cable and a small 1:1 transformer on a binocular ferrite core. I have two home-made ones used indoors and I use a BN73-202 core with 5 turns of 30 AWG wire-wrap wire for each winding of the transformer. Although better results are obtained with the Airspy HF+ or Discovery, it does give reasonable results with the RTL-SDR v3 and Spyverter. I have used a HiLego LNA from e-bay to improve results, but careful adjustment of its gain by varying the supply voltage was necessary. Fortunately I don't have any strong transmitters near me which might cause many spurious signals. As this LNA needs a supply of around 6 to 12 volts, depending on required gain, the dongle's bias-tee cannot be used. I use up to 8 rechargeable AA batteries. The e-bay UK link is as follows:

Ian Brooks, Verwood, UK.

On 02/01/2022 22:36, Paul Egan wrote:
I have a 10th floor balcony and would like a no tune solution for an rtl-sdr v3 with an upconverter.

I've tried a miniwhip from aliexpress. It was pretty deaf.

The youloop looks interesting but I think it needs a more sensitive SDR and using an LNA with the rtl-sdr v3 only elevates the noise from what I understand.

I have a homebrew magnetic loop for transmitting between 17m and 40m but tuning is cumbersome and I would like to receive below 7Mhz.

So what would you install to get a decent signal from 0.5 to 30Mhz? Some sort of passive loop?

Thanks.



.

Locked Re: What is your preferred antenna for SWL'ing on a balcony.

 

¿ªÔÆÌåÓý

Try this link from Martin, G8JNJ: or this one:

The diagram is the same as the one that appeared in the airspy group in 2017. The BN73-302 core is smaller than the BN73-202 core, but the -202 is probably easier to wind. Others have had good results with various toroid cores and ones salvaged from defunct USB cables or 75 to 300-ohm baluns. Room for some experimenting here. I actually used 75-ohm RG59-Mini cable because I had a lot of it, but it doesn't appear to be critical.

Ian.

On 03/01/2022 10:10, DX Pedro wrote:

mind sharing some links/diagrams for dummies like myself?
many thanks.
// pedro andrade


On Mon, Jan 3, 2022 at 1:53 AM Ian Brooks <ian.brooks4073@...> wrote:

The Mini-Whip antennas do not function very well indoors and probably not very well on a balcony. If you're into a bit of home construction, a YouLoop or Moebius antenna is definitely worth a try and is very cheap to build yourself as it is basically two short lengths of coax cable and a small 1:1 transformer on a binocular ferrite core. I have two home-made ones used indoors and I use a BN73-202 core with 5 turns of 30 AWG wire-wrap wire for each winding of the transformer. Although better results are obtained with the Airspy HF+ or Discovery, it does give reasonable results with the RTL-SDR v3 and Spyverter. I have used a HiLego LNA from e-bay to improve results, but careful adjustment of its gain by varying the supply voltage was necessary. Fortunately I don't have any strong transmitters near me which might cause many spurious signals. As this LNA needs a supply of around 6 to 12 volts, depending on required gain, the dongle's bias-tee cannot be used. I use up to 8 rechargeable AA batteries. The e-bay UK link is as follows:

Ian Brooks, Verwood, UK.

On 02/01/2022 22:36, Paul Egan wrote:
I have a 10th floor balcony and would like a no tune solution for an rtl-sdr v3 with an upconverter.

I've tried a miniwhip from aliexpress. It was pretty deaf.

The youloop looks interesting but I think it needs a more sensitive SDR and using an LNA with the rtl-sdr v3 only elevates the noise from what I understand.

I have a homebrew magnetic loop for transmitting between 17m and 40m but tuning is cumbersome and I would like to receive below 7Mhz.

So what would you install to get a decent signal from 0.5 to 30Mhz? Some sort of passive loop?

Thanks.



.

Locked Re: Is this Wellbrook wide aperture loop faulty?

 

On Mon, Jan 3, 2022 at 09:33 AM, Chris Wilson wrote:
Downside is MF / LF amateur digital performance has markedly deteriorated. Is it the smaller circumference of the new loop?
Hi Alan,

That looks good, your work has definitely made a further improvement.

I'm not sure how you are judging the change in MF/LF performance between loop sizes, but with the antenna connected, you still seem to have at least 10dB higher noise floor than the KiWi alone. Which is probably just about optimum. Any higher noise floor and you would e eating up the KiWi's valuable dynamic range, and any less, the wanted signals would start to become degraded by the system noise figure.

For the HF noise, as an experiment you could try some ferrite on the coax at the loop amplifier end of the cable. Looking at Steve (SK) G3TXQ's charts



Maybe 10 turns on an FT240-61 core seems to be the best option, but even just a few (4 or 5) clip-on style beads could be worth trying.

Keep on picking away at it, although it may bring diminishing returns it will be worth it, and if you kept any screen grabs of how it originally was, you will be able to see what a difference you have made.

Regards,

Martin
Locked Re: Is this Wellbrook wide aperture loop faulty?

 

On Mon, Jan 3, 2022 at 07:46 AM, John Kolb wrote:
However the losses in this approach might be higher than the slight loss caused by the mismatch of using the 75 ohm cable alone.
Hi John,

Yes that's the flaw in the plan, but apart from in lab grade stuff, equipment input and outputs are rarely the nominal impedance that they aim to be.

You can obtain ready built connectorised matching transformers specifically designed for the purpose of 50 / 75 Ohm conversion, which are sometimes used in applications where mismatch could be a concern, and these typically introduce around 0.5dB insertion loss. However the cost of decent designs is such, that it would probably be cheaper to buy better quality 50 Ohm cable instead.



Building one yourself is possible, but it does require a reasonable amount of effort to optimise the performance. The cheapest solution for many folks may be to buy a SMT transformer and put it in an enclosure of your choice.






Resistive 'minimum' loss networks can also be used, but they typically introduces just under 6dB insertion loss, which would be excessive in this application.



Regards,

Martin
Locked Re: What is your preferred antenna for SWL'ing on a balcony.

 

mind sharing some links/diagrams for dummies like myself?
many thanks.
// pedro andrade


On Mon, Jan 3, 2022 at 1:53 AM Ian Brooks <ian.brooks4073@...> wrote:

The Mini-Whip antennas do not function very well indoors and probably not very well on a balcony. If you're into a bit of home construction, a YouLoop or Moebius antenna is definitely worth a try and is very cheap to build yourself as it is basically two short lengths of coax cable and a small 1:1 transformer on a binocular ferrite core. I have two home-made ones used indoors and I use a BN73-202 core with 5 turns of 30 AWG wire-wrap wire for each winding of the transformer. Although better results are obtained with the Airspy HF+ or Discovery, it does give reasonable results with the RTL-SDR v3 and Spyverter. I have used a HiLego LNA from e-bay to improve results, but careful adjustment of its gain by varying the supply voltage was necessary. Fortunately I don't have any strong transmitters near me which might cause many spurious signals. As this LNA needs a supply of around 6 to 12 volts, depending on required gain, the dongle's bias-tee cannot be used. I use up to 8 rechargeable AA batteries. The e-bay UK link is as follows:

Ian Brooks, Verwood, UK.

On 02/01/2022 22:36, Paul Egan wrote:
I have a 10th floor balcony and would like a no tune solution for an rtl-sdr v3 with an upconverter.

I've tried a miniwhip from aliexpress. It was pretty deaf.

The youloop looks interesting but I think it needs a more sensitive SDR and using an LNA with the rtl-sdr v3 only elevates the noise from what I understand.

I have a homebrew magnetic loop for transmitting between 17m and 40m but tuning is cumbersome and I would like to receive below 7Mhz.

So what would you install to get a decent signal from 0.5 to 30Mhz? Some sort of passive loop?

Thanks.



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