G8JNJ

Oh I quite like that idea.

Maybe it could be linked to the user defined memories in some way too, and then perhaps a scan function could be added, with either timed or squelch controlled pause / resume.

However, I think John has more than enough to deal with at the moment, so I'd just leave it in the "possibly nice to have" future enhancement category / pile.

Regards,

Martin

Ah OK...

Personally, I wouldn't recommend that model, but let's see how it works for you, when used with your antenna.

I'm not sure what device the Noolec is using, but I guess it will be something like the Qorvo QPA4363A.

Rather than issues with MW stations, it's more likely to be issues with possible overload from any strong FM broadcast stations, or other VHF transmitters that may be around your location.

The reasons I suggested a PGA-103 based amplifier for your application are, good IMD performance, low noise figure and rising input impedance, which helps improve signals on the LF bands, especially when using a short antenna. The current consumption is a bit higher at around 100mA. Noolec may have chosen a lower power consumption device, so that it can be used with the limited current available from sdr's with built-in bias tees, many of which have a maximum current rating of around 50mA.

But experimentation is all part of the hobby, so just try it, and be sure to report back with your findings.

If you need any specific help, send me a PM.

Regards,

Martin

Regarding the DX Engineering RPA-2 pre-amplifier.

It's a good enough device, but somewhat expensive. I have used cloned copies of the RPA-1, which has a very good IMD performance, but the noise figure is not that brilliant, at around 6dB.

As your signal levels are quite low, I think one of the PGA-103 based pre-amplifiers that are available on AliEpress, such as this one, would be a good option.

https://www.aliexpress.com/item/1005005241002955.html

But you may need to add a 10dB attenuator on it's output, to bring the signal levels down to a more suitable average.

There are many other pre-amplifiers on AliExpress, that may work just as well or perhaps even better. But as most of the MMIC chips used in them only tend to be specified from about 500MHz upwards, I don't know how well they would perform on the short wave bands. From experience, the PGA-103 works well below 50MHz, and it's gradually rising input impedance, makes it suitable for use as an active antenna too.

Regards,

Martin

There was a long thread about the Apexradio 303WA-2 some time ago on this forum.

https://forum.kiwisdr.com/index.php?p=/discussion/comment/17853

The height of the antenna above ground is likely to have a significant effect on its performance.

Generally speaking, the higher you can mount it, the better it will perform.

Can you state your KiWi URL so that I can take a listen ?

Regards,

Martin

Thanks for doing that.

I think the Apex is better than the loop, but in both cases you seem to be constrained by local interference.

I can hear and see noise from several switching supplies, possibly solar PV optimisers, plus what I think is a domestic Data over Mains Powerline adaptor.

The sensitivity of the Apex falls off below about 5MHz, which is what I observed with my clone, but it should still be adequate in most cases, as the noise floor naturally rises on the lower frequencies.

Have you checked your own home for sources of electrical noise ?

Regards,

Martin

I recently did a bit more research into the various DC filter boards that can be bough cheaply from China.

I've previously mentioned the simple type with two separate inductors.

Simple DC Filter

But I wanted to compare it against some of the larger types with an additional common mode choke using a dual winding. All of these seem to use the same printed circuit board, but populated with different types of inductors.

Green rectangular core common mode choke, and black core inductors

With toroidal common mode choke and yellow / white core inductors (Type 26 Iron Powder)

Differential Mode attenuation - direct noise from the power rails

All the filters are pretty effective. The simple type is slightly worse, but I doubt you would notice much difference between them in "real life"

Common mode attenuation - conducted noise, usually via a ground path

The Green and White cored filters are much more effective. The White cored filter would be slightly better at reducing low frequency <1MHz switching noise from Switched Mode Power Supplies, but the Green cored version provides much better overall attenuation.

Note that the values of attenuation were measured in a 50 ohm system, and the actual amount of attenuation will depend on the circuit impedance. However, using 50 ohms does at least provide a standard reference for comparison purposes.

Regards,

Martin

It's not that easy, as it depends on the source, and whatever it is connected to.

Especially as John has already indicated that there is likely to be more than one source.

That's why I suggest switching off your power at the main board, you will then be able to see what is under your control, and what is external.

Bringing the power back up, breaker by breaker, should allow you to better narrow down the location of a noise source.

Concentrate on one specific signal at a time, some of them will appear on many other frequencies.

Get rid of the worst offender first, and then gradually work on the others.

Be as methodical as possible.

Regards,

Martin

Most likely you will, so good hunting.

Oh and folks will soon be turning on their cheap Chinese made Christmas lights and decorations, so expect things to get worse for a month or so, until they get packed away again ready for next year.

Regards,

Martin

Ah OK, like temporary user specific DX labels or were you something else ?

Regards,

Martin

I don't think you will be able to get in using WinSCP.

I'm experiencing similar problems since updating the OS version, and WinSCP doesn't provide the option to log in as su. I seem to remember reading a thread about it but can't find it.

Also, with Debian 11 to enable root login, you can add a line to the sshd_config file in /etc/ssh/sshd_config:

Edit the file as root using nano /etc/ssh/sshd_config

Add the line PermitRootLogin yes in the Authentication section

Save the file

Restart the SSH server using service sshd restart

I swear the Linux folks move the goalposts purely to keep us muggles at bay, but if you do find a solution, be sure to tell us, as this is turning out to be a real pain.

Regards,

Martin