G8JNJ
About
- Username
- G8JNJ
- Joined
- Visits
- 4,629
- Last Active
- Roles
- Member
- Points
- 127
Reactions
Comments
-
Hi Ben, Yes I had seen that design, unfortunately I think it would fall over in the presence of the European short wave broadcasters. But you may get away with it if it's only required to operate over a small (normally quiet) frequency range, in a …
-
> >broadband magnetic loop, digital mode, there was no obvious advantage beyond about 3db (lowest) increase in noise floor > That's highly likely. Glenn was spot on with his previous statement. > > It is more difficult to approach …
-
I've also not heard anything from GMF-11F. It's also not been listed (that I can find) in recent ITU or IARU intruder watch (7090 kHz is in the 40 meter amateur band) bulletins, so it's unlikely, but very occasionally stuff like this does spring u…
-
Good idea, displaying the cursor level would also be useful. Actually I'd like the frequency to be displayed along with the level on the spectrum display mouse over cursor balloon too, if it's possible. Regards, Martin - G8JNJ
-
Simply open a second browser session to bring up the antenna switch. You can do this if you ever wish to use more than one extension at a time, such as the S-Meter. Regards, Martin - G8JNJ
-
OK, thanks John.
-
Superb :-) Thanks (again) John.
-
Hi John, Any chance of 15min and hour markers too ? Regards, Martin - G8JNJ
-
Hi John, Thanks for adding pause to the S-Meter, it's made it a much more useful tool. Regards, Martin - G8JNJ
-
> >I suppose you could just drop the speed, make the change, bring it back up? > Yes I tried that but unless you remember the original speed setting you used or if you move the slider too slowly, it messes up the time scale. Regards, Ma…
-
Hi John, Thanks for adding that it's really useful. Having played wit it for a while I think it would be even better if it was possible to add a 'pause' button, so that you could halt the scrolling whilst you made any changes to the antenna or wha…
-
I use the S-Meter extension a lot and would also find this useful. Regards, Martin - G8JNJ
-
> >I wound the inductor on a T50-2 toroid. Quite a lot of turns, too many to count > For others who wish to copy Richard's circuit, it was probably about 73 turns according to mini ring-core calculator (free) http://www.electronicecircuit…
-
> >Does anyone else notice their KiwiSDR saying it is full when you try to use it, when it really is not per the admin panel? I've been noticing >that the last few days. The admin panel says there are two users, but it is full. > This j…
-
> > found that the notch was 34 dB deep, which was more than necessary. I 'softened' it to 20 dB with a series 2.2 ohm resistor. > Hi Richard, That's good, you must have found an inductor with a good value of Q. I've only ever been able…
-
Ha, that's a handy trick to compare waterfalls by switching tabs. I now understand the original question, and agree it would be a worthwhile addition. Regards, Martin - G8JNJ
-
Hi Stefan, OK understood. I mentioned it because of your previous comment "Unfortunately, I have too many peaks across the entire spectrum to notch." The point I was trying to make is that you have some margin for attenuation across the…
-
Hi, I'm not 100% sure what you are proposing, but I often try to do similar sort of things for antenna testing and usually resort to either taking screen grabs or using the S-Meter graphing option. Ideally I'd like to be able to use a modified spe…
-
@HB9TMC Hi Stefan, Just based on quickly looking at your screen grab (I can't find your KiWi on-line, so I wasn't able to play with it to be sure), as your noise floor is at least 20dB above that of the KiWi SDR, I'm assuming you are using some f…
-
Hi Mark, Here's a simple notch that should do the trick and give you a 20dB deep notch on 252KHz. It's just a series tuned circuit wired across the antenna feed into the KiWi. (Image) You may need to fine tune either the inductor or capacitor v…
-
> >I note that on the Seeed metal case, one of the endplates touches the ethernet connector along one edge. Is that intentional > The problem is that it doesn't make very good or consistent metal to metal contact. I found that if I 'wiggl…
-
Some interesting notes regarding the use of 75 Ohm resistors to provide "Bob Smith" termination in order to try and dissipate common mode signals, which I'd not previously encountered. https://electronics.stackexchange.com/questions/16143…
-
I suspect that part of the problem is that the values of filter components incorporated into the chassis mounted socket are not ideal for frequencies below 30MHz, which of course are the ones that are of interest to us. For example the 1nF capacitor…
-
Hi Stu, > >1. Without the SMA grounded/earthed and the antenna terminated (50 Ohm?) take an (above ground) antenna shield to the SMA >2. Same but shield to Ethernet or USB socket > Yes it's basically the same setup that you had for you…
-
Hi Stu, With the RF input to the KiWi terminated, what happens when you connect just the outer screen of your antenna to the outer of the KiWi SMA ? What happens when you connect the screen of your antenna cable to the metal screen on the KiWi Eth…
-
Hi Glenn, > > probably a GALi+ sort of approach for the LNA and a diplexer, that the two can push down pretty close to the ITU lower noise limit. > There are at least a couple of Mini-Circuits devices that have similar and usable IMD per…
-
Hi Glenn, Hmm, that's disappointing and somewhat unexpected, as my understanding is that some skeleton Bicones used for EMC measurement purposes have a 300 Ohm feedpoint impedance, and have an impedance transforming Balun built into them, as it's n…
-
Hi Glen, I've just realised that we had covered some of this ground before, in an email exchange back in December last year. My apologies for revisiting some of these themes. I think I'd better take some time to re-read the notes that I made at…
-
Hi Stu, Thanks for doing that, it's a bit too wet and windy here to try anything outside today. I'm a bit surprised that the levels of the broadcast stations below 1.6MHz are so similar in strength and also that the noise floor when used in 'dipol…
-
> >Adding inter-element capacitive reactance, sometimes called 'dead capacitance' doesn't change this > Agreed that is an issue, and a tube doesn't give quite as much improvement as you would expect. A wire frame inverted 'pyramid' dimens…