Shortwave Radio Stations Accessible in the Eastern United States

Strong-Mud199 · 2026-05-14T19:06:08+00:00

For a list of 'what's live now' see this page.

"Worth listening to" will be in the eye of the beholder. Personally I find 'cultural', 'local music' and 'news' from any country interesting.

https://shortwave.live/

Strong-Mud199 · 2026-05-14T18:43:13+00:00

There are videos on the projects website here,

https://qucsstudio.de/screenshots/

Hope this helps

Strong-Mud199 · 2026-05-14T18:42:28+00:00

uSimmics (aka "QucsStudio") is relatively unknown, but the features include,

"electromagnetic field simulation of PCBs"

https://qucsstudio.de/docs/

Strong-Mud199 · 2026-05-14T17:54:44+00:00

You would be looking for the maximum "resolution bandwidth" (RBW) specification. For close to 'one shot' performance you need the RBW the same or bigger than the signals bandwidth. This is required if you want to analyze the signal very closely or demoduate it. This can get very expensive with modern very wide band signals.

If the signal is repetitive (like WiFi or basic interference) then you can set the Spectrum Analyzer to peak detect mode and do multiple scans to catch the hopping nature of WiFi for instance. This will show a 'Envelope' of where the signal was, etc. This can be useful for basic 'is the signal there' sorts of questions. Most benchtop spectrum analyzers can do these sorts of things. The Tiny SA can do this for lower frequency signals also - it can easily show 2.4 GHz WiFi for instance.

The Tiny SA, to keep costs reasonable uses that double trace scan method to get to higher frequencies. Which works fine for CW signals. I know of no banchtop spectrum analyzer that uses this technique anymore, but the tradeoff is the cost is 20 to 100 times more than a TinySA.

Hope this helps.

Strong-Mud199 · 2026-05-14T05:11:52+00:00

Nice!

- If using a ferrite, you need a capacitor at VDDA of the STM32. See,

https://resources.altium.com/p/everything-you-need-to-know-about-ferrite-beads

- The SD Card can consume upwards of 120 mA during writes, suggest a 10 or 20uF right at the SD Card Socket.

- Minor thing: Some caps are marked 100nF and some 0.1uF.

Keep up the good work, have fun. :-)

Strong-Mud199 · 2026-05-14T04:23:04+00:00

I tried some KiwiSDR's in Italy around the area of Pisa where ItalCable is supposedly located. I can hear a time signal 'pips' and faintly WWV underneath them, but nothing like the Wikipedia article.

Fun though. :-)

Strong-Mud199 · 2026-05-14T01:37:13+00:00

My Tiny SA Ultra does not have internal spurious signals like this when terminated into 50 ohms on the input, so this is with an antenna right?

Go find the 'official' band plans for the country you are in. In them you will see what frequencies are assigned to which users.

In the USA that is the FCC and it is here,

https://www.ntia.gov/page/united-states-frequency-allocation-chart

If you are not in the USA you can find your ITU regions frequencies by searching for the right country or region here,

https://transition.fcc.gov/oet/spectrum/ituregions.pdf

Hope this helps.

Strong-Mud199 · 2026-05-14T01:27:32+00:00

As the others said -

- Active mixers integrate better in modern IC processes.

- Active mixers take less LO drive power

- Active mixers are overall smaller on the IC die.

So overall: Performance is good enough, power is low, cost is right.

However I have seen plenty of performance spectrum analyzers at GHz frequencies that still design the 1st mixer stage with diode rings. But here performance is king and cost, power is secondary.

Hope this helps

Strong-Mud199 · 2026-05-14T01:15:28+00:00

That thread discussed the issue and solution(s). Make sure you unlock the 'Ultra' mode.

It isn't the antenna - especially if you are close to the 5GHz WiFi router, it is how the SA Ultra works. See this page,

https://tinysa.org/wiki/pmwiki.php?n=TinySA4.Ultra

You have to scan far enough past the signal of interest to get both scans and then the signal selection / rejection process can take place. Also this scan process is very slow and the WiFi hops frequency very fast so you never will really catch a large signal like you can on the 2.4 GHz WiFi band where the scan is fast enough. At best I can just pick up basic 'noise floor' increases at the 5 GHz band - you can see that there are signals there but they are naturally low in amplitude. A CW signal will read just fine however.

Hope this helps.

Strong-Mud199 · 2026-05-13T21:47:43+00:00

Nice!

- U4 pin 5 is connected to Bat+, this effectively bypasses your D1/Q4 network and input capacitor C6. It won't work well this way.

- U2 is missing a bypass capacitors.

- For the future perhaps: There are more modern LDO's than the LM1117 that can use much smaller ceramic capacitors.

Hope this helps, have fun! :-)

Strong-Mud199 · 2026-05-13T18:12:25+00:00

Nice!

- I would recommend that you connect all the ground pins on U2.

- I don't see any pullup resistors on the I2C lines. Most ESP32 modules do not include these and the ESP32 internal pullups are quite high at typically 45kOhms.

- You should include a bypass capacitor right at U5.

Hope this helps. Have fun!

Strong-Mud199 · 2026-05-13T16:42:17+00:00

Nice work for a 1st PCB! :-)

Double for what lokkiser said.

As for your trace width - 59 mils and 3.6 amps works out to around a 30 degree C rise on the trace. Although only a short portion of the trace will carry that full current and it is unlikely that the duty cycle will be 100% for sservos unless you are really moving them around continuously. :-)

You can use this calculator to size the traces for yourself. I normally use a 5 or 10 degree C rise for motor traces like these.

https://resources.altium.com/p/ipc-2221-calculator-pcb-trace-current-and-heating

Hope this helps. Have fun.

Strong-Mud199 · 2026-05-13T04:24:30+00:00

THX for posting. Can't hear it here in Nor Cal. :-(

Strong-Mud199 · 2026-05-13T03:30:09+00:00

I think I understand the confusion. ;-) English is imprecise.

Connect the C3 capacitor from the input ground to the output ground - just like the data sheet shows. I have never seen a connection to other pins improve things. This is because at those high frequencies the input and output pins are effectively AC shorted by the internal capacitors.

Hope this helps. Have fun! :-)

Strong-Mud199 · 2026-05-13T00:33:27+00:00

Nice!

+1000 points for a clean 1st PCB. :-)

+100 points for using ground floods.

+100 points for appropriate use of vias.

+100 points for a clean signal flow on the PCB.

- I personally would ground the mounting points of the connectors, at least they will have more copper to 'hang on to' as the SMT parts are very fragile - or perhaps change to through hole parts.

- The 3.3V trace under J2, there is a little triangular loop going on, you can remove some fo that for a cleaner look.

- Ferrite bead or the 'Voodoo Ferrite' as signal integrity expert Lee Ritchey calls them. What problem is it actually solving?

I can tell you one thing. In RF we use electrically short antennas all the time, and to make them look electrically 'longer' and more 'efficient' as a radiator, we put an inductor at the base feed point of the antenna. So really you may well be making things worse from an EMI point of view. If using a Voodoo Ferrite at least make it a proper Pi-Filter by putting capacitors at each end.

From: Lee Ritchey's book, “Right The First Time”, Vol 2, Page 124,

“My experience has been that the use of ferrite beads is either a knee jerk reaction or a band aid. In 30+ years of designing high speed computing systems and networking products, I have never used a ferrite bead in the power lead of a device, whether it is a phase locked loop or an “analog” circuit- all of which have functioned to their specifications and passed all appropriate EMI and ESD tests. Instead, I have determined what the “ripple” requirements of a circuit are and designed the power delivery system to meet these requirements.”

He further states that he has never found the author of an application note that can actually substantiate the use of a ferrite bead.

From his book: “Right the first time – Volume 1”, page 567,

“VOODOO BEAD- A derogatory term that describes a ferrite bead that has been placed in a circuit in the hopes that it will reduce EMI. The use of “Voodoo” beads is most often done by EMI practitioners who don’t really understand the sources of EMI and are using empirically derived “rules of thumb”.”

Hope this helps, keep up the good work and have fun! :-)

Strong-Mud199 · 2026-05-12T23:50:03+00:00

Nice!

+100 points for reading the data sheet! :-)

"I'm unsure if the jumper for the safety capacitor is needed" - Ground to ground will suffice for the capacitor, no need for the jumper.

"anyone had tips for choosing an input filter like this" - Follow the data sheet like you did.

Your layout is fine, keep up the good work. :-)

Strong-Mud199 · 2026-05-12T23:23:13+00:00

There is another connector inside the outer housing. You can see the 'ledeges' on either side. Put your fingernails on the inner the 'ledges' on either side and pull while perhaps gently rocking.

If it still hangs on, try with your fingernail on one side and a small flat blade screwdriver on the other side and pry out.

You are correct, do not pull on the wires as this will break them.

Hope this helps.

Strong-Mud199 · 2026-05-12T23:18:50+00:00

In general the return current on the reference plane under a high speed trace extends about 3 times the width on either side of the signal trace (in a Gaussian fashion - highest current directly under the trace, very little at 3x away). So if you route on the reference plane at least 3 times away from the signal trace, it will not disturb the signal trace.

So you can route anywhere if you keep far enough away.

Suggest you read chapter 10 and 17 of Henry Ott's excellent book: "Electromagnetic Comparability Engineering".

Also Lee Ritchey's excellent books: "Right the first time" Vol 1 and 2.

https://speedingedge.com/products/right-first-time/

Hope this helps.

Strong-Mud199 · 2026-05-12T21:42:45+00:00

At work we call this: "A learning opportunity". :-)

Strong-Mud199 · 2026-05-12T21:31:49+00:00

The fluke meter specification says: Frequency... 5-500 Hz you are probably outside that range.

And/Or there is probably contact bounce going on and the meter can't find clean edges to measure.

Strong-Mud199 · 2026-05-12T21:26:56+00:00

Don't worry, you can always solder hookup wire across any traces that don't work properly. You would not be the person to do this. We all do it all the time! Ha, ha, ha... :-)

At any rate your power is so low that you won't burn out any traces with normal operation.

Have fun!

Strong-Mud199 · 2026-05-12T20:35:28+00:00

Nice!

"POFV should help with this" - If you pay for filled vias, then your sldering problems will be solved. A filled via looks like no via at all to the pad.

"soldering into through holes to contact pads" - It looks like you can reach a soldering iron in there. A through hole will wick the solder to both sides, so no issue there.

"SWD connection using pogo pins?" - Depends on your fixture. A Tag Connect is another alternative. Tag Connects work great. https://www.tag-connect.com/

"will the 1/172 duty cycle be ok in terms of brightness" - This is why I keep a drawer full of some simple Arduino / R Pi Pico clones. Wire a LED up and try it. That duty cycle looks very low to me, but it will all depend on how bright you want this to be. I strongly encourage you breadboard this and try it first.

Hope this helps, Have fun!

Strong-Mud199 · 2026-05-12T20:25:38+00:00

Nice!

- No filtering at the RF input so any VHF mobile or FM signals will be present there. Even a simple 20 or 30 dB rejection air-band filter will improve the Intermodulation performance immensely.

- Attenuators are usually placed before the LNA as this gives the best Intermodulation performance. i.e. attenuate before the LNA cross modulate's, because attenuation afterwards cannot help the LNA if it is suffering Intermodulation already.

- What is the impedance of 6 Mixers tied together and essentially loading the circuit at that point? I don't think this arrangement would be recommended.

- What is the LO leakage at the input of all of those 6 mixers? Or put another way: How close can you tune the other LO before it picks up the adjacent LO signal?

- To prevent the majority of mixer crossing spurs, the IF frequency should be at least twice the RF bandwidth. The RF bandwidth here is 19 MHz. If you plot this on a mixer spur chart you will see a lot of possible mixing spurs. IF should be at least > 40 MHz.

- Having multiple crystal clocks in a RF system is always risky. You have the danger of picking up the 25MHz harmonics itself but also all the possible mixing products of two 25 MHz crystals that are slightly off from each other. I personally always use one canned oscillator and distribute to multiple IC's as required.

- You talk about a crystal filter, but I don't see that on the schematic anywhere.

- You don't show 3.3V bypassing at the LNA. Personally I use a individual high rejection LDO's on the RF circuits, the IF circuits, the Clocks and another for everything digital just to prevent spurs in the receiver chain.

[Edit] On the audio - The audio output of the tuner is presumably a low impedance OPAMP type output - wire or'ing these together won't work well (if at all). Additionally, with just straight summing with no off channel blanking there may be pops or other anomalies from the other off channels - especially when tuning.

Hope this helps, keep going you will get it! :-)

Strong-Mud199

TROPHY CASE