[Premium-Rx] Racal 1772/78 receivers

[Williams, Barry]

If the Racal has a 455 KHz I.F. Stage Kiwa makes some very good filters that can be spliced anywhere in that stage.  I have a 6 KHz and a 15 KHz used to sharpen I.F. Stages in older receivers (National HRO).  You might also try tuning off the receive frequency a KHz or 2 to one side or the other for more high frequency recovery in the audio.

I use R-390A and SP-600 with synch detector from Sherwood.

73,
Barry,
KD5VC
------Original Message------
From: Master Lee
To: Thomas Adams
Cc: premium-rx at mailman.qth.net
Subject: Re: [Premium-Rx] Racal 1772/78 receivers
Sent: Aug 10, 2010 9:35 PM

Please explain as your statement is some what  lacking in detail

73 Lee
----- Original Message ----- 
From: "Thomas Adams" <quixote2 at ix.netcom.com>
To: "Enrique Fernandez García" <enriqueeeeee2001 at yahoo.es>; 
<premium-rx at mailman.qth.net>
Sent: Wednesday, August 11, 2010 8:38 AM
Subject: Re: [Premium-Rx] Racal 1772/78 receivers


> BTW...   re the WJ 8718;
>
> My shack also contains the AN/URR-74 (V) 2, the military version of the 
> 8718.
>
> For BCB DXing, the RA01772 beats it by a country mile.
>
>
> 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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