[Premium-Rx] Watkins-Johnson WJ-9040 IF bandwidths

[watkins-johnson at terryo.org]

The IF bandwidths in the 9040 series receivers are very easy to change. 
They are on plug-in cards.  The cards even output a voltage that tells the
processor which bandwidth is present.

This system was developed for the 8617/8618 series and carried over.  The
9040 makes it easier because the new IF automatically shows up on the LCD
display (and much more reliably than the goofy system in the Racal
RA-6970).  In the 8617/8618 you had to locate the corresponding button
cover or fabricate one from a blank.

The 9040 series even has the high/low bandwidth circuitry developed for
the 10IF  version of the 8617/8618 (sometimes called dually), though I
have never seen a dual IF card for a 9040 receiver.

The cards are the same in the -1 receiver/controller and the -4 handoff
receivers.  I think the cards may be interchangeable across all the entire
receiver line but I only know what I see in the manual for the VHF/UHF
handoff receiver (love to see copies of other 9040 component manuals).

If you are adventurous, you can even change the filters on the cards.  The
manual gives the corresponding component changes and it is nowhere near
rocket science to do the mods.

So, if you don't like the IFs, find a handoff receiver and swap cards or
buy filters and roll your own.  Handoff receivers often appear at
reasonable prices.

You must always bear in mind that WJ radios were not built as products,
they were built for projects.  They were not built to sit on a shelf as
inventory and be sold.  They were individually made for specific contracts
that an agency developed with a mission in mind.  Thus they are almost
always quite adaptable if you can find the requisite alternative
components.  For many things this is easier said than done, but not for
changing IFs.  That is relatively easy.

Terry O'
http://watkins-johnson.terryo.org

> George, It does look very tempting as this is a very high quality
> receiver.
> the problem is look at the bandwidths included. The Seller has been very
> upfront.  This combination of bandwidths is only good for listening to the
> local FM station unless youi have a baseband receiver to feed it to. If
> you
> want to monitor local public safety or any narrowband FM signals it is
> totally useless.
> ----- Original Message -----
> From: <Phoenix0754 at aol.com>
> To: <premium-rx at mailman.qth.net>
> Sent: Friday, November 13, 2009 8:04 PM
> Subject: [Premium-Rx] Watkins-Johnson WJ-9040 Broadband Radio HF VLF
> Receiver
>
>
>> Hello to all:  Ebay is at times a  great place to find things and
>> others,
>> sort of a rip off.
>>
>> Take a look at this great looking WJ-9040 system, Item #  390117892104.
>>
>> It is comprised of: WJ-8628-4-5 half rack receiver/controller,
>> WJ-8628-4/FE frequency extender
>>
>> WJ-8628-IF Demodulator & WJ-8625-1/HFE223 VLF  receiver
>> Enough to make your mouth water, well, mine a least.
>> Yet as I have found out over the last few months when you click  on the
>> bids and bidders, the site will list how many bids the particular bidder
>> has
>> with the seller.
>> In this case, w***g (232) has 100% with the
>> seller??????????????????????
>> Sort of a dead giveaway to the definition of  shell bidding.
>> Any way, just a thought to be careful.
>> Regards, George Michael
>> ______________________________________________________________
>> Premium-Rx mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/premium-rx
>> Help Page: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Premium-Rx at mailman.qth.net
>> Help Contact eMail:  paul at 8zo.com
>> Home Page:  http://www.premium-rx.org/
>>
>>
>>
>>
>>
>
>
> ______________________________________________________________
> Premium-Rx mailing list
> Home: http://mailman.qth.net/mailman/listinfo/premium-rx
> Help Page: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Premium-Rx at mailman.qth.net
> Help Contact eMail:  paul at 8zo.com
> Home Page:  http://www.premium-rx.org/
>