Messages

76

SDR - Software Defined Radio / Re: Kiwi SDR software tuning aside of the pointed frequency

« on: March 15, 2023, 0113 UTC »

This decoder improves the stability of the reception, because it partially eliminates the effect of selective fading of the AM carrier wave.

Yes and in many cases it can dramatically improve the quality of reception of very weak AM signals as well, "pulling them out of the noise" somewhat.

77

SDR - Software Defined Radio / Re: Kiwi SDR software tuning aside of the pointed frequency

« on: March 15, 2023, 0106 UTC »

Yep, I uderstand all that. But often, to escape the splashes, I have to go to USB or LSB.
I even use SAM with the sideband selection, SAU or SAL. Alas, in those modes, all too often, the sync is lost, and the audio is mashed. And when I see a carrier on the waterfall, I can't tell its exact frequency, I point on it, and the software tunes 1.5 kHz aside ! Then I have to make the panel come back, but it covers about 40 percent of the waterfall range on my small screen !

I understand the frustration.

I find that the default passband filters in SAL and SAU just barely include the carrier frequency and during fading, synchronization can be lost or come close to losing it. (This may have been improved in a recent software update.) To avoid or mitigate the possibility of sync loss when I am using SAL or SAU modes, I will usually adjust the passband filters to include the carrier and also more of the unintended sideband than is provided by default. This seems to lessen the possibility of loss of synchronization.

78

SDR - Software Defined Radio / Re: Kiwi SDR software tuning aside of the pointed frequency

« on: March 15, 2023, 0051 UTC »

The way I avoid that is by tuning in AM mode then switching to the one I am going to listen in.

Yes, also general tuning around in SAM or SAS in "large" frequency steps (greater than 1 KHz, for example) will generally produce a continuous tone when you finally stop and try to listen to an AM signal. This tone comes about because the inserted carrier that is inherent in synchronous detection (SAM, SAS, etc.) comes from a phase-locked loop (PLL) action (generated in software) that is not able to "lock" onto the AM carrier that you just tuned across because its lock range is much smaller than the tuning steps you were using.

The way to fix this is to momentarily switch modes to anything other than a synchronous mode (e.g., AM, IQ, etc.) then back into SAM or SAS, at which point the PLL can lock onto the AM carrier since the receiver is likely tuned very close to the actual carrier frequency and the PLL can lock.
 
In any case, I try to avoid tuning while using a synchronous mode for this reason but I sometimes forget and I use the method above to get out of the continuous tone mode and lock the PLL.

79

SDR - Software Defined Radio / Re: Kiwi SDR software tuning aside of the pointed frequency

« on: March 15, 2023, 0036 UTC »

When using the pointer on WF to change frequency,
if the mode is USB or LSB,
then the soft tunes aside, 1.5 kHz away from the pointed frequency, grrrrr....

Yes, I find this annoying but like many things I think that one becomes habituated to it and learn to modify my behavior.

This operation is different than, for example, WebSDR (e.g., Twente) but after many weeks of only using KiwiSDRs, I become used to it and attempting to use a WebSDR requires a few attempts to get through my stumbles as a result of the differences.

80

North American Shortwave Pirate / Re: UNID 6975 AM 2352 UTC 14 Mar 2023

« on: March 15, 2023, 0031 UTC »

0030 UTC - Good copy on an SDR in Ohio. S9+10 on peaks. SINPO 55334. Good modulation with 5-6 KHz bandwidth.

My bet is that this is Nowhere Radio.

0205 UTC - TX off suddenly mid-song, which is (was) typical of Nowhere Radio.

81

Amateur Radio / Re: Real time on-the-air spotting/sharing network?

« on: March 14, 2023, 2057 UTC »

As a licensed amateur who enjoys listening to all types of communications I've often wondered if it was possible to use HF amateur bands to share real time spotting information about whatever it is we happen to be hearing. (broadcast, pirate, utility, beacons, etc.)

Many decades ago there was a net for shortwave listeners on Sunday mornings on the North American east coast. In addition to folks checking in with loggings, there would always be some gateway stations who would accept loggings from SWLs via telephone and then would read them out over the air. Not quite real time but the idea is similar. This was just as the internet was just becoming more ubiquitous and not everyone had it at home. The net was run by KW3F, whom I believe has passed away.

82

General Radio Discussion / Re: Another radio store closes its doors.

« on: March 14, 2023, 2052 UTC »

It says very little. ... Tell us exactly which policies and how they affected you.

I took it to mean that it tells me a lot about the people that wrote it and their proclivity to blame other people for their issues, without feeling the need to be specific.

83

The RF Workbench / Re: U-LULU (Updated LULU) for 48 meters, 20 Watt Class-E AM Transmitter

« on: March 14, 2023, 1912 UTC »

My first build attempt at the U-LULU, with a board made by JLCPCB using CDS's gerber files.



Learning how to solder all over again with a hot-air rework pencil, great for the chip but how do I stop the tiny caps flying away 

On a test-jig I'm getting about 15w carrier, still more work to getting the output coil right and finding a suitable modulator.  Any ideas on something still available from China in 2023?

Very nice! I feel like a proud papa. I saw your DM too and you've obviously figured out posting photos on HFU and you have an additional 5 Watts since that DM so all is good. 

As for the power output, it would be good to know if you are trying to do this at 6250 KHz (as I did) or another frequency.

Using a different batch of PCBs (which is inevitable) and using a slightly different winding technique than mine (also inevitable) will introduce possibilities for variation. Your PCB manufacturer will likely have a slightly different material property (called Er, "E sub R" in the spoken lingo) than mine, meaning that you may want to adjust L2, C5 and C6 slightly to compensate. To tune L2, you can push and squeeze the wire of L2 a bit. 

One of the decisions I made during the design tuning was to sacrifice bandwidth for maximum power output and this means that the if you are trying to use this transmitter at 50-100 KHz away from 6250 KHz (approximately), you might not get the full output I claim. I think that it may make sense to also offer folks a broader bandwidth output tuning (which I have simulated in the computer but not built in real life) to make it a little less sensitive to my narrowband tuning I specified in 2021. My initial computer simulations suggest that I can get similar power output and broader bandwidth with a completely different set of L and C values. It remains to be seen if this is true in real life but when I verify I will update. I may also add a 43 meter band tuning option too.

For the modulator, perhaps you missed in the text (page 8 ) but I am recommending the Wondom AA-AB31184.
In North America, they are available here: https://www.parts-express.com/WONDOM-AA-AB31184-100W-Mono-Amp-Board-320-3341?quantity=1
In other parts of the world they seem to be available from Farnell in the UK, Audiophonics in France, AliExpress,  Ebay, Opentip, etc.

84

General Radio Discussion / Re: Another radio store closes its doors.

« on: March 04, 2023, 0337 UTC »

The problem is - the new millennials has the mindset that they want everything as cheap as possible and will shoot themselves in the foot to save $5

First of all, what you are describing is the effect that the Amazon way of doing things has had on retail capitalism.
Second, it's not just Ham Radio that has had this happen. Other hobbies that I am involved in have seen a hollowing out of the brick and mortar retail store - that was often the gathering point of local enthusiasts - at the expense of online business.
Third, it's not just millennials. As one data point, the median age of US hams is somewhat older than the median age of the general population. Think about the implications of that.

85

European Pirates and Private Stations / UNID 6280 AM 0030 UTC 04 Mar 2023

« on: March 04, 2023, 0032 UTC »

Electronic dance/hip hop but not sure in what language. SINPO 33333 in Portugal.

0100 - Finnish hip hop?
0114 - Has improved to SINPO 44444 in Portugal and the UK. Continuous trance/dance type music.
0139 - suddenly off the air mid-song.

86

European Pirates and Private Stations / Re: Zeppelin Radio 6290 AM 1900 UTC 03 Dec 2022

« on: March 03, 2023, 2302 UTC »

I am listening via Portugal. SINPO 33433 / S7 with some slow QSB at 2300 UTC
My SDR indicates that the carrier frequency is 6289.89 KHz.

~2300 UTC - ID and announcements (multiple times) in English between songs.
The operator said that he will stay on "all night" with a program of Greek music.

0022 UTC - S9+10 in Italy.
0143 UTC - The carrier is audible weakly in North America. Far too weak to listen to even on some of the best receivers (K3FEF and K1VL).
0244 UTC - long break with dead audio. The signal is still very good in the UK.
0300 UTC - still dead audio. I have to go. Bye Bye.

87

North American Shortwave Pirate / Partial India Radio 6935 AM 0138 UTC 03 Mar 2023

« on: March 03, 2023, 0140 UTC »

Lots of audio problems. Most of what I heard was a throbbing sound, though I did hear "Partial India Radio" clearly.
0141 - Audio continuously moving between inaudible and throbbing.

You have RF getting into your audio, my friend. That's what the squealing is. You need to invest in some ferrite torroids.

0147 - some clear audio but has to keep it at a low level to avoid RF feedback. Not a good place to be.
0148 - carrier off
0155 - back on. Audio is better...maybe. No about the same.
0156 - ID
0200 - Audio is low but usable. Sanjay talking.
0205 - More audio futzing. Some RF feedback and then carrier off.

Sorry, man. Keep trying.

88

North American Shortwave Pirate / Re: Yeah Man Radio 6925 USB 0055 UTC 03 Mar 2023

« on: March 03, 2023, 0056 UTC »

DK is quick on the mark. I saw the start up on the waterfall, logged in and he had already started the thread. 

0056 - jazz. I have them at around 6925.01 KHz on an SDR in New York State.
0104 - ID.
0121 - For what it is worth, just noting drift down to ~6924.98 KHz. Well above the static, easy listening. The "flamethrower" machine has opened up on the LSB but not bothering at all.
0207 - Off

DangerKitty don't play. I quit school because of recess.

Cat-like reflexes.

89

North American Shortwave Pirate / Re: Partial India Radio 6935 AM 0019 01 March 2023

« on: March 02, 2023, 0045 UTC »

Using the K1VL SDR in Vermont.

The carrier is plenty strong but the somewhat under-modulated and restricted audio makes it difficult to understand what is being said, especially when there is a static crash, which is every 2 seconds or so. There is minimal audio energy above 1 KHz and everything you hear is between 350 and 900 Hertz. As we say out here, "No bueno."

90

North American Shortwave Pirate / Re: UNID 6925 USB 2303 UTC 1 MAR 2023

« on: March 01, 2023, 2338 UTC »

Very good reception

1810 Instrumental Music.....then "Where's Skippy(?)"  Voice sounds like Stumpy ID person.
1817 "I just had sex with ______?", then off.
1819 Music back.
1823 Another selection starts, stops suddenly.  OM "Hey Now" (?)
1824 Music
1828 OM talking over music, tough to understand.

Times should be in UTC, not EST.