[Premium-Rx] Racal 1772/78 receivers

[Enrique Fernandez García]

I purchased a 'non standard' unit,came from RAF, with these filters fitted 0,4, 1,24, 2,7 and 8 Khz has the ISB option fitted with AFC.
 
 It affects mainly the mode and bandwidth features.  Later I did some modifications on the USB and mode swiches in order to have a 'standard' set.  I removed the 0,1 Khz filter, some wire links need to be changed, and added a 6,8 Khz filter instead. ( Thanks Dan for your help ! ).
 
   The difference in listening with the 6,8 and the 8Khz filters it is noticeable but for my taste and use I would need something more narrower.
 
Mainly I use it for AM BCB Dxing on tropical bands but when I need to identify a weak station I use the LSB filter with fair results.
 
My only complain it is that when I try to listen a faint signal it is quite difficult to understand the ID or the speech, audio it is too bassy and it would need a better audio recovery so I will try the ELPAF audiofilter.
Quite sure that a better headphones would mark a difference but I have still not found the perfect match.  I tried the Japan Radio Company ST-3 but no significant improvement.
Another good option would be to install a 600: 8 audio transformer and listening with 8 Ohms headphones.
 
Now, I am thinking about to get a 1778 , but I do not know if I really need it or with the 1772 it is enough.
On latter posts somebody asked for the WJ 8718A receivers , they are again for sale at a fair price.
 
 http://cgi.ebay.com/Watkins-Johnson-WJ-8718A-HF-shortwave-receiver-/180532736925?pt=LH_DefaultDomain_0