[1000mp] RES: Significant audio difference between LSB/USB RCVR A only

[Marcus - PP5MS]

Hi Ron,

How are the "SHIFT and WIDTH" controls on front panel? Item #44 on page 15
of the user manual.

73,
Marcus - PP5MS


-----Mensagem original-----
De: 1000mp-bounces at mailman.qth.net [mailto:1000mp-bounces at mailman.qth.net]
Em nome de w4lde
Enviada em: quarta-feira, 26 de janeiro de 2011 13:18
Para: 1000mp at mailman.qth.net
Assunto: [1000mp] Significant audio difference between LSB/USB RCVR A only

I recently sold and shipped my FT1000mp, it was triple boxed with the 
rig received in excellent condx at the new Owners end.

A few days prior to ship I removed the Collins 500Hz filter to test in a 
different Yaesu rig and did not return it to the old FT1000mp since I 
also had installed a IRAD 500Hz filter plus a 250Hz and two (2) 2.1kHz 
filters.  Pretty sure I set the filter menus correctly prior to ship, 
however, the new Owner had an issue with the sound and difference in the 
pitch of the audio in USB/LSB in the receiver A (main) where the RCVR-B 
sounds OK.

Trying to narrow down this issue I recommend that a CPU reset be done 
plus I recommended that we consider changes in menus 8-9 to compensate 
and that he not try any hidden menu 9-0 changes, his response and 
background are as follows:

 >>>>>>>>>>>>>>>>>>>>>
/On 40 meters, with no discernible signal, just white noise,  in LSB the 
pitch of the white noise is a low frequency rushing sound, while in USB, 
a higher pitched hissing sound. This is with 2.4 kHz IF filters in 
place. This would indicate a different issue than just noise.  Tonight I 
will carefully remove the covers, and check the filters, connectors etc. 
and make sure everything is seated.

and

I reseated all cables and filters, and reset the CPU.  Things are 
better, but I still think there may be an alignment issue.  With no 
antenna connected, just listening to white noise, the pitch is very 
different when toggling between USB and LSB.  High pitched hiss on one 
and low pitch rush on the other.  Any ideas/
 >>>>>>>>>>>>>>>>>>>>.

Other comments from the new Owner are:

 >>>>>>>>>>>>>>>>>>>>>>>>>
/In a nut shell, the only real issue is with receiver A when switching 
between USB and LSB.  Even with no antenna connected the white noise 
pitch is very different.  This is NOT subtle there is no high frequency 
hiss in LSB, just a low frequency rush. _*Receiver B does not have this 
problem*_, the back ground noise is almost identical; when switching 
between USB and LSB.  All my other HF rigs act the same way, there is no 
difference in sound when switching between USB and LSB.  This is the 
same listening to a signal or just receiver noise.  I have limited my 
use to just receiver B

and:

I did make the full range of adjustments on menus 8-9  and 9-0.  Even at 
the extremes, it was nowhere near enough to balance out the response of 
USB and LSB/

 >>>>>>>>>>>>>>>>>>>>>>>>>>>

Any comments or recommendations where to look next prior to shipping it 
off for service is appreciated.  I am going to recommend removal of the 
roofing filter but I would think that it effects the performance of rcvr 
B but I do not have the manuals and can't review the tech manual.

73 de
Ron W4LDE




______________________________________________________________
1000mp mailing list
Home: http://mailman.qth.net/mailman/listinfo/1000mp
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:1000mp at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html