7440 drm

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SCPD

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Has anyone been able to decode this DRM station from RNZI?

For the life of me I cannot get this station to lock in properly. At best, I get up to MSC CRC and that fails and prevents the audio from coming through.

Any ideas would be helpful...

I'm using the latest version of DREAM.

I've tried changing the AGC and various other settings in the program to no avail.

PS. I should mention that my signal level is +10db over S9 and this is pretty typical.
 

ka3jjz

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I believe that it's more the soundcard input levels that you need to fool around with. I played around a bit with DRM when I had my modified RX320, and found that putting a small pot in line made adjusting the levels a bit easier. If you can't reduce your input levels via the Soundcard control in the system tray enough, I'd suggest this.

The DREAM software, like most soundcard based software, is very sensitive to being overdriven.

HTH...Mike
 

SCPD

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Mike,

I forgot to say in my OP that my problem is only with this one station. The RNZI 17Mhz station works fine. I've been able to decode other DRM stations.

It just seems to be with this particular frequency/station.

Update: I'm listening to 17675 DRM right now which is RNZI's 17Mhz station. Decode came up w/o any adjustments from me. The 7440 station isn't up right now so I can't compare.

I'll see if there's some way to attenuate the RF signal. The signal right now is not quite S9 -- S8.5 or so. Perhaps I need to attenuate the stronger station.

I'll give it a shot and see what happens.
 
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ka3jjz

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It's not the RF signal strength you might need to adjust, it's the level of the signal going to the soundcard. From what little playing around I did with this, DRM is a very touchy mode when it comes to signal levels and decoding. If it's strong enough to be heard w/out fading or interference, you should be good to go. Just watch those signal levels to the soundcard.

Mike
 

ka3jjz

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Well, DREAM does it, but not exactly 'on the fly' (and it is pretty much the defacto standard). The fly in the ointment is that many receivers (and some wideband radios) need a detector tap - in principle, very similar to a discriminator tap in a scanner - to make it work.

We have several resources - including a few links for receiver modifications, and the Dream wiki, here - (with apologies to Clint Eastwood) at the bottom of....

DRM - the Good, the Bad and the Ugly

HTH...Mike
 

majoco

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Dream works just fine on my WinRadio G303 as it already has a 12kHz IF in the soundcard - the only trouble is I'm too close to RNZI and too far away from all the others - the only one I can get with any regularity is AIR in the early morning!
 

SCPD

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It's not the RF signal strength you might need to adjust, it's the level of the signal going to the soundcard. From what little playing around I did with this, DRM is a very touchy mode when it comes to signal levels and decoding. If it's strong enough to be heard w/out fading or interference, you should be good to go. Just watch those signal levels to the soundcard.

Yes, I understand what you're saying. I just don't get that a specific DRM station would be uber-sensitive to the AF input while all other DRM stations decode fine.
 
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