Sensitivity of a Logik LOG R128D DAB/FM Radio

[Old Sparky]

To me, this DAB/FM set (identical to a Ferguson FRG-R121D) is insensitive on both FM and DAB.  Compared to my Ferguson FRG-R116D stereo FM/DAB Portable, it receives fewer stations, and is more 'hissy' at the same location ( a ground floor flat in North Oxfordshire) on it's telescopic aerial.  There is no provision to connect an external aerial on either radio, and I have no instrument which can check DAB frequencies (Does such a thing exist?), though I do own a good AM/FM signal Generator.  Is anyone familiar with the R128D/FRG-R121D) by any chance?  BTW these use a 'Radioscape' HS002 module, rather than the more common 'Frontier Technology ones.

[ppppenguin]

DAB should never be hissy. If the signal is too weak you get lots of horrible noises but not hiss. If there is hiss on DAB it's either on the transmission or a really horrible bit of design in the receiver.

[Old Sparky]

I've now opened up the LOGIK radio, checked connections, having previously reconnected the coax. cable between the T/S aerial and the RF PCB. It's now playing away on R.5 live DAB perfectly OK, so I'm not sure what the problem is/was.

[JohnBS]

Sadly, there are some pretty dire DAB radios out there: a common problem is self-interference, whereby the digital sections of the radio radiate or conduct back into the RF front-end. The BBC has measured some radios which fall short of what you might expect (with, say, a modest antenna and a 6db noise figure) by some 30dB !!

John

[Old Sparky]

I was being too optimistic in post #3. There is an intermittent fault somewhere. The next day the radio wouldn't power up at all. As to dire DAB radios, no doubt there are a few, but my own Ferguson FRG-R116D, the Logik LOG-R128D, and it's Ferguson FRG-R121D 'clone' seem quite well made, and decent performing sets, although I've not carried out any signal to noise, or other tests on any of them. My FRG-R116D has one odd problem on it's FM band, in that it won't receive R. Oxford on 95.2 due to a kind of 'beat whistle' around that frequency. I did wonder if that was due to interference from the L.O. due to Smooth radio on 105.7Mhz (105.7-10.7 being 95Mhz) This would, of course be the case if the FM L.O. is below the incoming frequency. No other radio I have suffers from this phenomenon, though!