Messages

181

Spy Numbers / South Korean V24 may be inactive since late Sep, 2020

« on: November 29, 2020, 2346 UTC »

I have not been doing much radio stuff recently, but I have been doing my scheduled and programmed recordings and spectrum captures.  Those go on automatically as long as the hardware is turned on, and it has been on 24/7 even if I have been doing other things.  For V24 I capture and chart signal levels on all known past V24 freqs, including freqs they have not used in years, and record IQ files of scheduled transmission windows plus a bit more spectrum just in case.

Today I sat down to update the V24 schedule, which I last updated in March of 2020.  To do that I basically played back all the recordings and spectrum captures since March during the time period of 1000 to 1700 UTC daily.

It turns out V24 has not transmitted, to the best of my knowledge, since late September.  In September V24 made two of its nine schedules, or 6 of a possible 27 transmission.  It transmitted on 6215 kHz, on days 5, 7, and 9, at 1500 UTC each day, and it transmitted on 4900 kHz, on days 23, 25, and 27, at 1530 UTC.  So the last V24 transmission I am aware of was September 27, at 1530 UTC, on 4900 kHz.  And for several months prior to that it was at a much lower than normal rate of activity.

Of course there are several possibilities, the simplest is they may have shifted to a new schedule with new times and frequencies I have not captured.  Or they may have just taken one of their unexplained pauses.  In 2015 V24 did not transmit from 16 June to 26 November, one theory is that they changed transmitter facilities during that time period.

So, is V24 gone?  Or is it just taking a rest?  Or did COVID slow it down?

T!

182

Utility / Re: S/S Time station 10000 AM 2249 UTC 24 Nov 2020

« on: November 25, 2020, 1307 UTC »

At a guess it is station LOL, Buenos Aires, Argentina. 

T!

183

Utility / Re: OTHR? 13.400

« on: November 25, 2020, 1256 UTC »

Although typically people just call this CODAR, there are actually CODAR and WERA found in that section of spectrum.  And yes, CODAR and WERA are both radars that work over the horizon, but generally when you say OTHR people picture military radars or radars designed to track aircraft, ships, or missiles.  So for my logs I do not call these OTHR, rather I call them Coastal Radar.

T!

184

HF Beacons / Re: New whooper beacon on 4095.6

« on: November 24, 2020, 1625 UTC »

I just got this here at the house for the first time, and I have looked pretty often since it was first reported.

1620z, 24 Nov, 2020, peaking up to S3 and fading in and out of the S1 noise floor here, so a bit of QSB.

T!

185

North American Shortwave Pirate / Re: Wolverine Radio 6960 USB 0004 UTC 22 NOV 2020

« on: November 22, 2020, 0116 UTC »

S8 to S9 into the Mojave Desert of California tonight.  House sound system is rocking so the wife can enjoy.

T!

186

HF Beacons / Re: New whooper beacon on 4095.6

« on: November 17, 2020, 2225 UTC »

No real idea about the new dasher, other than I first saw it about a week ago.  At times it is very strong here, other times unheard at all.  It seems that I hear it best about an hour after local sunrise.  At first I thought it was night time only (I did not see it in daylight for the first few days in a row), and that it might be related to the other new dasher on 7999.2 kHz (they have the same or very similar cycle times), and thought maybe shifting daytime/night time freqs.  But then I saw the 4097.2 during the day, and have seen it pretty much every day since.  However, I have not yet seen 4097.2 and 7999.2 at the same time, so they still could be related.

T!

187

HF Beacons / Re: New whooper beacon on 4095.6

« on: November 17, 2020, 0308 UTC »

No sign of DW here, and I was looking about the time you posted.  I do, however, see, the assumed new 4097.2 beacon (2 sec on, 2 sec off) fading in and out.

T!

188

HF Beacons / Re: The new "L" Beacon

« on: October 17, 2020, 1358 UTC »

I ran into this beacon, or I assume it is the same L beacon, on 4102.39 kHz today, just below Windy.  Since I have not checked the beacons in several months I have no idea how long L has been on this freq.

T!

189

North American Shortwave Pirate / Re: Diamond City Radio / Enclave Radio 6952 USB 0458 UTC 17 August 2020

« on: August 17, 2020, 1531 UTC »

I am sorry I missed this.  Was busy so not at the radios, and the recordings show only the weakest of traces, but if I had been at the radio I could have turned an antenna around to peak the signal.

It was not Travis on the mic, was it?

T!

190

HF Mystery Signals / Re: Need help on multi-tone signal ID

« on: August 16, 2020, 1615 UTC »

I have heard this same signal. Im in Colorado. Freq is 14.102. There was some cw right before it transmitted. Was just a callsign.
W0ECM. No qrz page. I have many recordings of this signal and have been tracking it for a while now. I have also heard it at 40 meters. Hope this helps!

Do you have a recording of the signal you heard?  There are many similar ham radio MFSK modes, and 14102 kHz would be in a ham band.  14102 is also around the location of a lot of different MFSK modes, like DominoEX, Olivia, Contestia, etc.  However the signal being discussed here has not been reported in a ham band.  The take away is that it is very possible the two modes, the original and yours, are not the same but may sound similar.  A recording of your signal would help.

T!

191

HF Mystery Signals / MOVED: STANAG on 3805?

« on: August 12, 2020, 2256 UTC »

This topic has been moved to Utility.

https://www.hfunderground.com/board/index.php?topic=70377.0

192

General Radio Discussion / Re: Vintage analogue/ tube receivers for BCL/SWL DXing?

« on: August 12, 2020, 2255 UTC »

How would it compare with the more domestic looking yet popular receivers such as Panasonic RF-2200 and RF-3100?  Because I know a very serious BCL DXer who sold his other good radios to buy the RF-2200.  I was wondering if it was a good idea to sell more modern radios, and buying the ancient vintage like RF-2200? But I thought there might be something that I don't know about the RF-2200 that he knows.

On MW BCB the FRG-7700 is not as good as on HF.  And the RF-2200 (I still have my RF-2200 that I bought new in 1983 or so) is very good on MW BCB.  So it is quite possible the RF-2200 will beat the FRG-7700 for MW BCB, but I really think it would come down to antennas.  If I can have a nice mag loop or a full sized antenna I would prefer the 7700 to the 2200 on MW BCB, but if I am antenna limited the RF-2200 might be the better option.

On HF the 7700, with a decent antenna, should be better.

I’ve never used the RF-3100, so I can’t speak to it.

Talking about the receiver over loading, is it not the case that all receivers overload at nights when the medium bands strong stations come into the right skip? They are heard all over between 2 - 5 Mhz at certain time of the nights due to them getting really strong with the night time MW skip changes in the bands?  Many radios will suffer from this regardless the size of the antennas, unless they are using the built in whips.

And if fed with a cheap active antennas, then it could happened any time of the day from my experience. But are there receivers more robust in this problems?

While it is technically possible for any receiver to overload, it should not be the case that all receivers overload at night on the lower HF bands.  None of the receivers I regularly use have much of a problem with this, although some of the lower end vintage receivers I break out will, especially if they are single conversion receivers.  A receiver with good dynamic range and image rejection should be able to handle anything thrown at it by any passive antenna one might find.  Overloading and images should be the exception, not the rule.

Portable receivers often have issues with overload and images, but decent desktops are much less prone to this problem.

By their nature portables tend to be less robust when it comes to front end design.  They are built to primarily work with their built in, small, inefficient, whip antennas.  A portable on a good sized external antenna may indeed overload or show image often.  And such a radio on an active antenna is asking for it to happen.

T!

193

General Radio Discussion / Re: Vintage analogue/ tube receivers for BCL/SWL DXing?

« on: August 12, 2020, 0112 UTC »

The FRG-7700 is not a bad radio.  It is not particularly good (when compared to really good radios, like the NRD 525, Drake R8, or something), but not bad.  It competes well with other receivers in the same price class and age, it was a mid cost entry / mid level desktop in the day.  I have owned several over the years, and still own the original one I bought new in 1980.

The review on eham that states low sensitivity, wide filters, and overloading is valid, but the question becomes, what was he used to?  I find it hard to believe the two he lists, the FRG-7 and the R-1000, were any better.

The FRG-7700 sensitivity, by spec, is about 0.5 uV in SSB mode in the HF range.  The Sherwood Engineering tests showed their example at about 0.2 uV, my current copy runs about 0.24 uV for 10 dB S/N in 2.7 kHz.  This is not bad, but certainly not top shelf.  Fortunately raw sensitivity is not often an issue on HF, where you tend to be noise limited, not sensitivity limited.

The FRG-7700 does have limited filters, 3 filter widths in AM (12 kHz, 6 kHz, and 2.7 kHz), one width in SSB and CW (2.7 kHz) and one width in FM (15 kHz).  This amounts to a fair selection of usable bandwidths in AM, an adequate "normal" filter in SSB, and a far too wide filter in CW.  And while you can always change the filters out for different ones, there are not multiple selections for each mode, so you still only end up with 3 in AM, one in FM, and one for both SSB and CW.  And if you put in a nice tight CW filter then it makes SSB almost unusable.  From the filter aspect the radio was pretty obviously aimed at the SWL primarily listening in AM, that wanted SSB, CW, and FM capabilities also.

As for overloading, yes, I have seen FRG-7700s do that, but typically in pretty extreme situations.  While they can overload I have not seen it as a big problem with them.  And if / when it does overload you can crank down the gain.  There is a front panel variable attenuator, and there is also a back panel local/DX switch.

The FRG-7700 is an in between tech radio, a world that really only existed for a few years.  It is an all solid state radio with a digital display, but it is not a digital radio.  Yes, it has a digital display, but the radio itself and all the frequency sources inside it are analog (unless you have the add on external memory module), using crystals, PLLs, and similar sources.  The digital display is a digital frequency counter that is used to measure and display the analog VFO frequency.

The FRG-7700 is a decent desktop that works well, if not a stellar performer.  If you compare it to top end radios it will come up short, but if you compare it to lower end desktops, like the Radio Shack DX-302, it is quite good.

T!

194

General Radio Discussion / Re: Vintage analogue/ tube receivers for BCL/SWL DXing?

« on: August 08, 2020, 1420 UTC »

Can vintage analogue / tube radios be used for SWL BCL Dxing?
Do you use one? What are they? How do they perform?

Any advantages or disadvantage for BCL/SWL DXing using one of those vintage analogue radios?

As you have seen from the responses so far, yes, absolutely, you can use a vintage or tube receiver (often called "boat anchors") for SWL BCL, or any other kind of listening, if that is what you want.  And some of them can perform extremely well.  If there is a major weakness it is that some older radios, especially if they were lower end sets back in the day, can be a little less sensitive above about 15 MHz.

Advantages, cool factor, sometimes sound quality, and really that is about it.  There is nothing an old radio can do that a quality modern radio cannot do.

Disadvantages, many.  They can be a bit less stable in frequency, they can take a long time to warm up, they can be hard to find parts for, they use way more power and can warm up a room (both a plus and a minus, depending on time of year), they often have less adjustable or more limited filtering, etc.

If it sounds like I am running down the vintage stuff...far from it, I love it.  But there are things to consider if you are going to use older stuff.

Here I use a variety of older gear.  The core radios in the shack are modern, various SDRs and traditional modern receivers, but I also keep a couple older radios in play all the time, and I rotate the old radios used in the shack.  Today I have a Hallicrafters SX-28, Hallicrafters SX-62A, and Hallicrafters SX-71 in the shack, and an LM-18 right next to them (more on that later), a couple of months ago it was a National NC-173, Hammarlund SP600, and Hallicrafters SX-42.

I guess the main problem could be finding out what the exact freq, it is tuned to, when heard stations for the first time in languages that I don't understand.
And to go to the exact freq. to tune up for a station that I want to listen to.

I suppose a digital readout receiver could be used side by side to confirm the freq. but then it is not 100% analogue receiver at work is it?

Another thing is that, if you want to monitor a station on the freq. let say 4055 kHz Radio Verdad from Guatemala.
Then how would you be able to ensure your analogue tube radio is tuned for that freq. spot on?

You could use a digital frequency meter on the LO or VFO of the old radio.  There are many kits to do so.  You are still using only the vintage radio, but you have added a digital readout to the vintage electronics.  Pretty easy and it can be non-invasive, if you are careful in the implementation you can return the radio to original configuration with no sign it ever had the readout associated.

Or you can do it how we did it back in the day.  Use an external, period correct, frequency meter or frequency standard.

An external fixed frequency standard can be turned on that will generate multiple signals / markers on known frequencies.  They generate multiple harmonics of a given frequency, for example in the 1 MHz setting they generate a tone / marker / signal every 1 MHz (1000 kHz), so they are at 1, 2, 3, 4, 5....et MHz.  In the 100 kHz setting they generate a signal every 100 kHz, so it would include things like 3500, 3600, 3700, 3800, 3900...8100...15400, kHz, etc.  And in the 10 kHz setting they generate markers every 10 kHz, 3500, 3510, 3520, 3530, 3540 kHz, etc.

In your Radio Verdad example on 4055 kHz: you click the switch on the freq standard to the 1 MHz position.  Even very coarsely defined frequency scales can normally allow you to get within one MHz.  You tune the radio to 4000 kHz by finding the tone / signal of the freq standard.  You then click switch to the 10 kHz position, tuning the radio up until you have counted 5 tones, you are now at 4050 kHz.  Tune to the next tone up, now at 4060 kHz.  Go back to half way between (by sound or by dial indicator) the 4050 and 4060 kHz tones and you at 4055 kHz.

It sounds bulky, but is really very easy.

My favorite way would be an external harmonic frequency meter, like the military surplus BC-221 series, or the LM-XX (multiple numbers in the XX) series like an LM-12 or LM-18.  These systems can tell you the frequency of any signal you want or preset the frequency of the radio with an analog radio to under 0.1 kHz resolution.

Quite a while ago I put together a basic web page talking about these frequency meters, and how to use them:
http://www.tokenradio.net/token/BC221.htm

From that page you will also see a link to some boatanchor dials, and why such a meter can be helpful.

T!

195

Utility / Re: LINK-11 6928 USB 2245 UTC 27Nov15

« on: August 02, 2020, 1451 UTC »

I believe this is a 6928.5 kHz ISB transmission of Link 11 out of Europe or that general region.

T!

what is link 11 is it military or general com's, also what is ISB' I dont understand.

Nova

Link-11 is military.  Link-11 is a tactical data link that allows one platform (ship, aircraft, submarine, etc) to share its tactical picture with any other platforms in the network.  If one ship in a task group sees a target on its radar (sonar, passive sensors, etc) that track data is passed out to everyone, so everyone can see that track, even if their radar or other sensors cannot actually see the target.  There are many advantages to such a system, but one might be that of 12 ships in a task group only one has its radar turned on, providing a radar picture to everyone while the other 11 ships do not give away their position or condition by their radar emissions.

Link-11 was developed for the US Navy, but it has become a NATO forces standard.  It is in the process of being replaced by Link-22.  As Link-22 is backwards compatible to Link-11, this signal might actually be Link-22 in a Link-11 mode.

ISB is Independent SideBand.  This is sending both USB and LSB at the same time, but potentially with different data in each sideband, doubling the data rate.  Or,  alternately, a single frequency can support two different Link-11 networks, with some platforms in both networks, and some in either or.

T!