Unknown Station on 19010 KHz.

[RedBaron1070]

Hello all. First time here, and i'd like to talk about a catch I caught these last two nights on SW. At around this time. 0200 UTC - 0400 UTC, there is an asian sounding station on 19010 KHz. Last night, there were playing asian music, and tonight, there are two ladies speaking in english (based off of their accent, also chinese as well) about economical topics in China. So far, I have not been able to find any source online that logs this station. Has anyone on here found this as well?

[MDK2]

I don't find a listing, and the fact that you heard spoken English makes my hypothesis a bit unlikely. But what I'm guessing you heard was a Chinese shortwave broadcast that was intended to jam a so-called clandestine station called Sound of Hope  (or SOH). That clandestine is operated by the members of Falun Gong movement whose MO is to try different frequencies anywhere on the band and transmit their message into mainland China. The authorities of the PRC, not desiring that, have an elaborate network of transmitters, which I believe are coordinated by satellite, and usually broadcast their national station China National Radio 1 (CNR1) on the same frequencies at high power. They employ this against other unwanted signals such as VOA, Radio Taiwan International (RTI), Radio Free Asia (RFA) and others that transmit in Mandarin but are found within the regular SW broadcast bands.* SOH will go nearly anywhere on the bands, presumably with permission of other authorities that make sure they're not stepping on the toes of other regulated SW broadcasters, but China is pretty quick to find them and stomp on them with their own broadcasts. Since they're so powerful, that's what we in North America usually hear.

Now, the problem with my hypothesis is the fact that you heard English. While CRI (China Radio International) goes out to the world in different languages including English, CNR1 is a domestic service and should be in Mandarin only. (Other CNR stations come in different languages spoken within China.) So unless they are now using CRI to jam (and your description sounds like it could have been CRI), maybe you heard a harmonic. But that's also unlikely because dividing 19010 by 2 gives us 9505 and CRI doesn't use that frequency, and dividing by higher numbers results in answers to decimals rather than something rounding to 5. Other spurious transmissions seem just as unlikely since China has some of the best engineered broadcasts on the airwaves.

Where are you, and what receiver and antenna were you using when you copied this?

* Not every non-PRC broadcaster with a Mandarin program gets blocked. NHK World Japan in Mandarin has never been jammed that I've found, for example.

[Josh]

Also, what rig are you using to tune it?

[RedBaron1070]

I used an RTL-SDR dongle with a rigged outdoor dipole mounted antenna.

Here is an audio recording from the first night I encountered the station.

https://drive.google.com/file/d/1Ztk91eZQN7z5EQKtzqhnrgELNLuUvbEL/view?usp=drivesdk

I caught this on the west coast where I reside in Southern California.

[ChrisSmolinski]

I used an RTL-SDR dongle with a rigged outdoor dipole mounted antenna.

It is almost certainly an image from another frequency.

[RedBaron1070]

What do you mean by an image? As in some other frequency is being heard on this one as well, like resonance?

[ChrisSmolinski]

What do you mean by an image? As in some other frequency is being heard on this one as well, like resonance?

An image is when a receiver picks up a station on one or more other frequencies, in addition to where you should hear it. RTL dongles are unfortunately notorious for doing this on HF. Most likely it is being overloaded with signals that are too strong. It only has an 8 bit A/D, so not much dynamic range. They're OK for use on VHF/UHF (I am using one right now to listen to my county's trunked radio system on 900 MHz) but not really suited for HF.

[Pigmeat]

Get a good double conversion radio with knobs. Single conversion knobless radios are nothing but trouble.

[JimIO]

Could be the 28800 khz clock of the RTL - 19010  = 9790 khz

https://www.shortwaveschedule.com/index.php?freq=9790

[RedBaron1070]

Be it as it may, I was not aware that RTL's were not good on HF. I mean, I have received my fair share of long distance SW stations using it (Radio France, Radio New Zealand, BBC Madagascar), so I assumed it was good enough to use as a start.

Are there any good HF receivers that you guys would recommend? (Hopefully nothing too expensive, i'm not that high up there in finances lol)

[MDK2]

Be it as it may, I was not aware that RTL's were not good on HF. I mean, I have received my fair share of long distance SW stations using it (Radio France, Radio New Zealand, BBC Madagascar), so I assumed it was good enough to use as a start.

Are there any good HF receivers that you guys would recommend? (Hopefully nothing too expensive, i'm not that high up there in finances lol)

Yeah, those dongles are intended for VHF/UHF. It's not that they can't receive HF, but they lack the power to reject a lot of muck that's out there.

Here's hoping that your budget allows you to spend at least $100.

If you want a good receiver, Tecsun portables are good and relatively cheap. I have a PL-600 model and while it has its drawbacks (enough that I'd recommend the slightly more expensive but superior PL-660), I'm impressed with how well it does with a decent external antenna. It's especially good at selectivity, which is the word that describes a receiver's ability to reject unwanted signals.

If you're hooked on SDR, your best bet for an inexpensive one is the SDRplay RSP1a. That has wideband coverage too, all the way up to two GHz. If you don't need that sort of coverage, the Airspy HF+ is well regarded but I think it's more expensive than the RSP1a these days.

[MDK2]

Could be the 28800 khz clock of the RTL - 19010  = 9790 khz

https://www.shortwaveschedule.com/index.php?freq=9790

That's very likely. That particular is broadcast from Cuba and is in Cantonese at the time the recording was made, which is what the clip sounded like to me.

[ChrisSmolinski]

Could be the 28800 khz clock of the RTL - 19010  = 9790 khz

https://www.shortwaveschedule.com/index.php?freq=9790

That's very likely. That particular is broadcast from Cuba and is in Cantonese at the time the recording was made, which is what the clip sounded like to me.

I agree, this is quite likely.

If you're going to use an external antenna, I would shy away from portables, you can get overloading problems as well.For about the same money as a portable, you can get an SDR with much better performance and features. The SDRPlay is probably your lowest cost option, and gives you the widest frequency range if that is important. I have not yet had the chance to test the new AirSpy Discovery which is just hitting the streets now, but have an AirSpy HF+ and it is a good performer also. I'm hearing good things about the Discovery though from some early testers.

[Josh]

Be it as it may, I was not aware that RTL's were not good on HF. I mean, I have received my fair share of long distance SW stations using it (Radio France, Radio New Zealand, BBC Madagascar), so I assumed it was good enough to use as a start.

Are there any good HF receivers that you guys would recommend? (Hopefully nothing too expensive, i'm not that high up there in finances lol)

I think they're trustworthy on hf up to around 14MHz, above that you're in "image" territory as you've gone beyond half the sampling rate. Harry Nyquist and all that.
https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem
https://sites.google.com/site/g4zfqradio/sdr-transmit-and-receive-image-rejection

[ChrisSmolinski]

Be it as it may, I was not aware that RTL's were not good on HF. I mean, I have received my fair share of long distance SW stations using it (Radio France, Radio New Zealand, BBC Madagascar), so I assumed it was good enough to use as a start.

Are there any good HF receivers that you guys would recommend? (Hopefully nothing too expensive, i'm not that high up there in finances lol)

I think they're trustworthy on hf up to around 14MHz, above that you're in "image" territory as you've gone beyond half the sampling rate. Harry Nyquist and all that.

They only sample at about 3 MHz or so max. People either use upconverters or direct sampling mode hacks to use then on HF.  And they're just 8 bits, which is not nearly enough dynamic range for HF. They're problematic at best outside VHF/UHF.