[Premium-Rx] Racal 1772/78 receivers

[Thomas Adams]

Hello Enrique!

The first 1772 I got was also one of the 
nonstandard RAF units, with the ISB and AFC installed. I found
these optional features to be VERY useful for AM BCB DXing.

If you engage the AFC option, it locks on the 
incoming carrier... giving you synchronous detection! In
this mode of operation, the choice of ISB 
sidebands makes it easier to dodge interference.

The filter lineup you describe is identical to the ones in my radio.

Mr. T. / W9LBB





At 13:36 10-08-10, Enrique Fernandez García wrote:
>
>
>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
>
>
>
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