[Elecraft] Impossible mission? USB with the 13khz filter for PSK31on Digipan

[Joe Subich, W4TV]

> OK so are you saying that the K3 right now receives a maximum 
> of FM 4Khz of AUDIO which translates into a received RF 
> bandwidth of better then 5Khz, so there is no problem?  If 
> that is what you are saying then I think I got it now.  

Please get a copy of The Radio Amateurs Handbook or other 
technical text that describes the operation Frequency Modulation. 
Explaining FM and the relationship of maximum modulating (audio) 
frequency, deviation, and occupied (RF) bandwidth.  In simple 
terms they are related by Carson's Rule which says that 
RF bandwidth is equal to twice the sum of the highest audio 
(modulating) frequency plus the deviation.  

In the K3 the RF bandwidth is fixed at 13 KHz (FM filter). 




> -----Original Message-----
> From: Thomas Tumino [mailto:thomastumino at yahoo.com] 
> Sent: Friday, January 30, 2009 11:23 PM
> To: elecraft at mailman.qth.net; lists at subich.com
> Subject: RE: [Elecraft] Impossible mission? USB with the 
> 13khz filter for PSK31on Digipan
> 
> 
> > I can only speak for Yaesu and Icom gear, but Yaesu
> > rigs specify 5Khz transmit FM in their manuals and in
> > the Icom 706MKIIG service manual states FM deviation
> > is adjusted for 4.5Khz.
> 
> There is a BIG difference between FM deviation and 
> maximum modulating frequency (audio response).  I was 
> speaking specifically to maximum modulating frequency. 
> 
> As Lyle has said elsewhere, the maximum modulating 
> frequency in the K3 is limited to about 2.8 KHz - in 
> all modes except ESSB - which results in an occupied 
> bandwidth of about 15.5 KHz with 5 KHz of deviation 
> for FM.  
> 
> OK so are you saying that the K3 right now receives a maximum 
> of FM 4Khz of AUDIO which translates into a received RF 
> bandwidth of better then 5Khz, so there is no problem?  If 
> that is what you are saying then I think I got it now.  
> 
> 73,
> Tom
> 
> 
> 
> 
> 
> > -----Original Message-----
> > From: Thomas Tumino [mailto:thomastumino at yahoo.com]
> > Sent: Friday, January 30, 2009 1:33 PM
> > To: lists at subich.com
> > Subject: RE: [Elecraft] Impossible mission? USB with the 
> > 13khz filter for PSK31on Digipan
> > 
> > 
> > 
> > 
> > No, typical transmitted bandwidth for communications use -
> > including FM is about 100 Hz to 3000 Hz.  
> > 
> > I can only speak for Yaesu and Icom gear, but Yaesu
> > rigs specify 5Khz transmit FM in their manuals and in
> > the Icom 706MKIIG service manual states FM deviation
> > is adjusted for 4.5Khz.  I would assume
> > this was the standard for all Yaesu and Icom gear
> > at least.  Some Yaesu rigs do have a special 
> > "FM-N" transmit mode of 2.5 Khz, similar to FRS radios,
> > but I think that mode is the exception and not 
> > the rule. 
> > I think the DSP receive limit of 4Khz should at least
> > be mentioned in the K3 materials (or perhaps it 
> > is and I missed it?).  This bothers me as
> > really I feel FM and AM are most regularly used 
> > to enjoy audio of a better quality then SSB audio, 
> > and a 4Khz limit cuts down on that a bit.
> > 73 to all and thanks for your
> >  help,
> > Tom-N2YTF
> >  
> > 
>