Watkins-Johnson

[KC9RGF]

Just picked up a Watkins-Johnson 8718. Unfortunately there was no manual to go with it. Anyone have any experience with these? Where can I get a manual?





Scott

[WQ9E]

Scott,

The manual is here:  http://www.criticaltowers.com/General%20Web%20Pages/Ham%20Stuff%20Page.htm

I have a WJ 8716 which is nearly identical to the 8718.  It is a nice receiver with great AM audio.  The only issue I have had with mine is once in awhile the frequency will go down no matter which direction you turn the tuning encoder knob. It is very rare and self clears in a couple of minutes so I haven't bothered trying to run it down yet.

I have mine rack mounted with a Racal 6790GM and I prefer the WJ however after acquiring a Telefunken E-1501 and a SRT CR-91 a couple of years ago I REALLY like the performance of the Telefunken mechanical filters used in both of those receivers.  High end receivers are definitely fun to play with and some, like the WJ 87XX series , do make nice station receivers paired with a transmitter.

[KC9RGF]

Thanks for the link.

This should be quite the upgrade from my Nationals - an NC-125 and and NC-300. 

[Fred k2dx]

Here is a WJ website: http://watkins-johnson.terryo.org/WJ-CET-index.htm

I have a 8718-15 that originally came from NSA.

Run the audio through a hi fi amp and a good speaker.

[KL7OF]

Rodger...
How do you mute the WJ and the Racal when using with a transmitter?

[WQ9E]

Both receivers feed a solid state audio amp that I set up with relay controlled muting and the receiver antenna input is also grounded by the same relay.  This has worked fine for me.    The SRT CR-91 is equipped with a muting jack and the Telefunken E-1501 might have this capability also but I don't have much on it in English so I use the same audio muting system for it as I do the WJ and Racal receivers.  My E-1501 also has an aftermarket board that adds memory storage and that took awhile to figure out without documentation since it relies upon using a combination of the existing up/down and fast/normal tuning switches to read and write memory locations.

I believe that some Swedish amateurs were heavily involved in the CR-91 design so even though it was designed as a surveillance receiver it makes a very nice amateur receiver.

[k7yoo]

The WJ is a neat Rx. I still have one in the rack as a mainstay. If you dig into the archives that Terry keeps, look at the price list. These receivers were $20K back in the 80's!!
That is when we were still using dollars, not dollarettes
Skip

[KC9RGF]

Here is a WJ website: http://watkins-johnson.terryo.org/WJ-CET-index.htm

I have a 8718-15 that originally came from NSA.

Run the audio through a hi fi amp and a good speaker.

Thanks Fred

[KC9RGF]

The WJ is a neat Rx. I still have one in the rack as a mainstay. If you dig into the archives that Terry keeps, look at the price list. These receivers were $20K back in the 80's!!
That is when we were still using dollars, not dollarettes
Skip

They're still a bit pricey on the used market 

[KC9RGF]

Both receivers feed a solid state audio amp that I set up with relay controlled muting and the receiver antenna input is also grounded by the same relay. 

Do you have any idiot proof instructions for that? 

I'd like to lash it up to my DX 100 but I fear disaster...

[w3jn]

The WJ 8716/8718 has one of the sweetest sounding AM envelope detectors ever - but make sure you use slow AGC mode to take full advantage.

The front end is a tad fragile and susceptible to damange when used in a transmit/receive situation.  Make sure you isolate the antenna input adequately using a shorting relay.  The M9 double balanced mixer is unobtanium and connects directly to the antenna thru a low pass filter, but it can be replaced with a MiniCircuits DBM with a bit of PC board surgery so it's not completely unrecoverable.  Easiest not to wreck it in the first place with excessive power - and that means don't leave it hooked to another antenna in close proximity to your transmitting antenna.

Another problem spot is the backup battery - best to remove it before it leaks all over the circuit board and destroys it.  It can be replaced with a remotely-mounted cordless phone replacement battery pack.

I recently got mine going again.  Several out of tolerance resistors and a bad transistor in the IF filter module.

[KC9RGF]

I'm having second thoughts about lashing it to the DX 100. Perhaps I'd be better off sticking with the Nationals and use the WJ as a dedicated receive station.

Thanks for all of the input guys.

[WQ9E]

Just do as John says and provide the antenna shorting relay.  It is a very nice sounding receiver and will be fine with proper setup, no need for it to turn into a "part time shelf queen" 

Better to use and enjoy equipment than worrying about it blowing up.  Just be careful and almost anything can be fixed.  One of the folks I knew while I was in Lubbock had a very nice woodworking shop set up but he spent more time polishing the tables on his band saw and table saw than cutting wood.  I think he was afraid the wood might scratch the cast iron surface.  Guys using much less expensive Craftsman shop equipment were making a lot more sawdust than he did with his expensive setup.  When I stepped up to more expensive Delta and Minimax (Italian) machines I resolved to put them to a lot of use but these last few years they have been sitting mostly idle.  This fall I am going to take a hiatus from radio restoration and get back into the wood shop.

[KC9RGF]

The WJ 8716/8718 has one of the sweetest sounding AM envelope detectors ever - but make sure you use slow AGC mode to take full advantage.

The front end is a tad fragile and susceptible to damange when used in a transmit/receive situation.  Make sure you isolate the antenna input adequately using a shorting relay.  The M9 double balanced mixer is unobtanium and connects directly to the antenna thru a low pass filter, but it can be replaced with a MiniCircuits DBM with a bit of PC board surgery so it's not completely unrecoverable.  Easiest not to wreck it in the first place with excessive power - and that means don't leave it hooked to another antenna in close proximity to your transmitting antenna.

Another problem spot is the backup battery - best to remove it before it leaks all over the circuit board and destroys it.  It can be replaced with a remotely-mounted cordless phone replacement battery pack.

I recently got mine going again.  Several out of tolerance resistors and a bad transistor in the IF filter module.

I opened up the WJ today so I could check out the back-up battery. Boy oh boy did I get lucky. It had just started leaking, battery holder has some crud on it but the circuit board looks good.

[K4RT]

Here is a WJ website: http://watkins-johnson.terryo.org/WJ-CET-index.htm

Fred,

From the link you provided I found a page on that web site devoted to the humble beginnings of Communications Electronics, Inc. in Bethesda, Md. (with photos) and its growth and eventual acquisition by W-J. I found the story very interesting. Here's the link if anyone's interested:

http://watkins-johnson.terryo.org/history/CEI-history.htm

[WA1QHQ]

I have a few, probably need to thin out the herd a little. They are all built A la Carte with many options to choose from. There should be an option tag on the back panel to identify what options you have. Hopefully you have the ISB option, most were equipped with this. I bought all of mine in non-working condition but found them easy to repair and most of the parts are still available. You already found the leaky memory back-up battery which is good. I mute mine by shorting the antenna input and disconnecting the speaker with the my antenna T/R relay. The 8718 has one of the most user friendly front panels of any receiver I have used.

Mark WA1QHQ

[W3RSW]

Our former FCC enforcer , Riley Hollingsworth would be very proud of you guys. "One Big Knob" and only two little ones.    . I think his 2009 (?)  forum at Dayton was very apropos.

Very nice construction.

[KC9RGF]

I have a few, probably need to thin out the herd a little. They are all built A la Carte with many options to choose from. There should be an option tag on the back panel to identify what options you have. Hopefully you have the ISB option, most were equipped with this. I bought all of mine in non-working condition but found them easy to repair and most of the parts are still available. You already found the leaky memory back-up battery which is good. I mute mine by shorting the antenna input and disconnecting the speaker with the my antenna T/R relay. The 8718 has one of the most user friendly front panels of any receiver I have used.

Mark WA1QHQ

No option tag on the back      Serial # 1183. It does have ISB and remote input but no monitor output card. When I went looking for the battery I noticed that there wasn't any open slots for additional cards, so I am assuming it has most of the options.

[Opcom]

While on the subject of the wj receivers, does anyone have the book or a decent plugin for this one?

R-1723(P)/GR
contract DAAB03-70-C-0349
MFR 14632

It's wj/CEI - they seem to be the same, was there a transition at some point?
With a set of functions like those, what's not to like?
I've had it since 2009, never been able to find a tuner or manual. including on the archives above. Thought to ask again.