Re: [IRCA] 918 kHz DU English Puzzle

[Gary DeBock <d1028gary@xxxxxxxxxxx>]

Chuck,

Even for an Ultralight-genre recording, the 918-Cambodia MP3 posted earlier (recorded at 1658 UTC on April 12th) did have some rough edges, primarily for the reasons detailed below. A reworked recording (attempting to compensate for too much recording amplitude) is posted at https://dreamcrafts.box.com/s/c9y3nrzcv7fq6bvru7jnut47uh6bmyx4 , but it's much easier to get good audio by setting the recording level properly during the time of reception rather than by going back and attempting to improve things.

Unlike communication receivers, Ultralight radios do not have a line-out recording jack, and the DXer needs to manually set the volume control to a level which results in an MP3 which is not too wimpy, but also not distorted. The digital recorder level (on the Sony ICD-SX68, in my case) also needs to be manually set, but that level is far less critical than the volume control on the Ultralight, which can easily clip off high frequency audio if the DXer is a little too aggressive.

The main problem in the Cook Islands was that transoceanic propagation was far more intense than anything a west coast DXer would normally experience, even on the ocean coasts of Washington or Oregon. The recording levels typically used at such locations needed to be thrown out the window on the Aitutaki beach. Almost every Cook Island MP3 would have been overdriven if a "Grayland" setting had been used at Aitutaki. Adjusting to this new reality was a learning process, and the "lesson" didn't always go smoothly. The 918 MP3 featured a four-station mix (Cambodia, Shandong and two DU English stations), all rising and falling in a random pattern-- a typical arrangement in Aitutaki. Initial recording level was probably set for a moderate-level mix, not for the wacky free-for-all zoo that was the end result. Such is the challenge of Ultralight DXing at an intense-propagation site like the Cook Islands-- but I don't think it will discourage other "Frequent Flyer" DXers from coming here :-)

Gary


> On April 24, 2018 at 12:24 AM Chuck Hutton <charlesh3@xxxxxxx> wrote:
> 
>     Gary - 
> 
>     The amplitude level of the recording would have no relation to the DSP filtering.
>     And the DSP filtering and tuned circuit Q might roll off a bit of the audio frequencies above a few kilohertz, but I wan't trying to point out that rolloff. Instead, the audio rolls off starting about 300 Hz. A bit of equalization was able to restore a flat passband to almost 1700kHz. To my ears, the equalized, higjh pass filtered file is distinctly easier to understand, YMMV. 
>     There are 2 mono tracks in your audio file, causing a larger file.
> 
>     Chuck 
> 
> 
> 
> 
>     ---------------------------------------------
>     From: Gary DeBock <d1028gary@xxxxxxxxxxx>
>     Sent: Monday, April 23, 2018 8:28 PM
>     To: Chuck Hutton; Mailing list for the International Radio Club of America
>     Subject: Re: [IRCA] 918 kHz DU English Puzzle
>      
>     Thanks for your investigation of the 918 file, Chuck and Theo.
> 
>     <<< It was a difficult file to study. The level was way too high: Audacity tells me it had to be lowered by 7 dB just to prevent clipping. After adjusting the level I then had to adjist the equalization as it was very muffled/ >>>
> 
>     Both the 1 kHz DSP filtering of the C.Crane Skywave Ultralight model and the very high-Q tuning system of the FSL antenna tend to clip off the higher frequencies in received DX station audio. The extent to which this side effect occurs depends somewhat on the gain provided by the FSL antenna, with the larger models clipping off more of the high frequency audio. Although improvements have been made in recent Ultralight DSP chips, it is still unrealistic to expect the Ultralight + FSL combination to have the audio fidelity of a $1000 Perseus-SDR + broadband antenna, unless the Ultralight's DSP filtering is set at a level too wide for serious transoceanic DXing.
> 
>     Gary
> 
> 
>         > > On April 23, 2018 at 6:04 PM Chuck Hutton <charlesh3@xxxxxxx> wrote:
> > 
> >         Gary - 
> > 
> >         At 2:44 I hear a phone number and a  mention of "Kingdom Builds.com". The number is difficult but sounds like 4654 5805.
> > 
> >         And I caught the same mention of Merv Starr at 4:37.
> > 
> >         It was a difficult file to study. The level was way too high: Audacity tells me it had to be lowered by 7 dB just to prevent clipping. After adjusting the level I then had to adjist the equalization as it was very muffled/
> > 
> >         Chuck
> > 
> > 
> > 
> > 
> > 
> >         ---------------------------------------------
> >         From: IRCA <irca-bounces@xxxxxxxxxxxxxxxx> on behalf of Gary DeBock <d1028gary@xxxxxxxxxxx>
> >         Sent: Monday, April 23, 2018 4:53 PM
> >         To: America, Mailing
> >         Subject: [IRCA] 918 kHz DU English Puzzle
> >          
> >         In the same Cook Island 918 kHz MP3 as Cambodia and Shandong (recorded at 1658 UTC on April 12th) there are two DU English stations mixing at a strong level from 2:40 until 6:00 into the recording, one of which builds up strength until 4:36 with a strong "Midnight, with Merv (?) Starr" mention. Can anyone (Theo?) decipher the DU English to provide any identity clues? Thanks in advance!  https://dreamcrafts.box.com/s/takoyz5d3l19wockuky8x1e0d8m8fiv0 https://dreamcrafts.box.com/s/takoyz5d3l19wockuky8x1e0d8m8fiv0
> > 
> > 
> >         Gary DeBock (in Puyallup, WA, USA
> > 
> >         .
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> > 
> >     >      
> 
 
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