Fw: [Premium-Rx] Hagenuk RX1001 and DRM reception

[Michael O'Beirne]

Good evening fellow listeners,

I am sure that Fabrizio gets excellent reception on the Milano Siziano DRM 
station on 693kHz, but you won't receive that in the UK because our BBC 
Radio 5 Live broadcast is also on that frequency at 150kW from Droitwich 
(and also other sites, though with much less transmit power), and will 
flatten pretty much everything else.

The 6,095kHz DRM station is quite strong here and seems to be a lot wider 
than 10kHz.  I personally regard DRM as a highly anti-social mode, and is 
not clever when the signal level is low (which of course is when you most 
need a robust system).

The likely reason why Fabrizio has to offset his tuning is because the 
Hagenuk may have separate sideband filters, each displaced into its 
sideband.  The frequency of the panel LED display usually shows that of the 
nominal carrier, and hence with a displaced USB filter, you have to tune 
down to bring the signal within the passband.

You get a related issue with NATO army HF frequencies.  The defined 
frequency is not the nominal carrier but is roughly the centre of the 
transmission.  To make life easier for everyone, the dial on the radio on 
USB (the Army don't use LSB) is actually 2kHz higher than the nominal 
carrier.  So if you wanted to listen to the BBC on 9410kHz (as one did to 
catch the news when life was getting a bit boring), you set the backpack on 
USB to 9412kHz.  The frequency offsets got complicated when operating to 
other military units if they were using "civilian" gear, particularly on 
FSK!

73s to all,
Michael
G8MOB


----- Original Message ----- 
From: "Fabrizio Magrone" <fabrizio_magrone at tin.it>
To: <premium-rx at mailman.qth.net>
Sent: Sunday, July 29, 2007 3:25 PM
Subject: [Premium-Rx] Hagenuk RX1001 and DRM reception


>
> Hello,
>
> I'm testing my new Hagenuk RX1001M receiver. It has a 10 kHz IF output to 
> connect a recorder, but I was wondering whether it could be used for DRM 
> reception.
>
> As you know, to listen to DRM broadcasts you need a 12 kHz output, usually 
> downconverted from a 455 kHz IF, connected to your PC's soundcard; a 
> software such as Dream then decodes the DRM signal.
>
> The Hagenuk's 10 kHz IF is not too far from the 12 kHz baseband requested 
> by the DRM decoder, so I connected the output to my soundcard, launched 
> Dream and... well, yes, it works.
>
> Thanks to the service manual kindly made available to the PremiumRX 
> community, I had all the information I needed. The 10 kHz IF output is a 
> 4-poles DIN socket; signal is available on pins 1 and 4 (the two lower 
> pins in the socket).
>
> I used a shielded two conductors wire: the two wires connected to pins 1 
> and 4, the shield to the receiver's case. You get a strong audio signals 
> and the 10 kHz IF output must be set to a low level, at least in my setup.
>
> I set the receiver to USB mode, with the widest selectivity available (6 
> kHz). I had to offset the frequency from 2.0 to 2.4 kHz lower than the 
> transmitting frequency. For instance, Milano Siziano is transmitting on 
> 693 kHz but I had to tune to 691.0 kHz; RTL is broadcasting on 6095 kHz 
> but I had best decoding when tuning to 6092.6 kHz.
>
> DRM reception isn't excellent: signals must be strong for good copying and 
> you need careful tuning, probably because the 6 kHz selectivity is too 
> narrow; I don't think that the 10 kHz IF output, instead of 12 kHz, is a 
> problem. But if you have got a R1001 and you want to try to listen to DRM 
> broadcasts, you can have a try.
>
> 73
>
> Fabrizio
>