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THE AM BULLETIN BOARD => Technical Forum => Topic started by: WO4K on August 12, 2017, 02:22:43 PM



Title: Viking II Civil Defense version
Post by: WO4K on August 12, 2017, 02:22:43 PM
Today I acquired a Viking II Civil Defense version. Eventually it will replace my DX-100B as AM transmitter. Factory assembled. Looks unmodified...EXCEPT for that vernier dial added to the front. Appears the CD decal is original and has not been moved. The vernier dial is attached to...nothing. Doesn't look like it ever was attached to anything. Can anyone advise if this dial ever had a CD-version function on the Viking II?


Title: Re: Viking II Civil Defense version
Post by: w4bfs on August 12, 2017, 03:07:41 PM
being that vernier dial is oriental and not origional its was maybe for a vfo add on and could do so


Title: Re: Viking II Civil Defense version
Post by: DMOD on August 12, 2017, 03:34:26 PM
It is not on mine, must be an add-on.


Phil - AC0OB


Title: Re: Viking II Civil Defense version
Post by: WO4K on August 12, 2017, 04:14:14 PM
Thought so. Looks like someone started a mod, installed the dial, and then decided not to do it. Hmmm. Thanks for that link, Phil!


Title: Re: Viking II Civil Defense version
Post by: WO4K on August 13, 2017, 07:40:56 AM
Phil, how good is the audio on your Viking II CDC? Did you have to do any of the Viking II audio mods? I ask because the audio circuit in this CDC beast is different than a standard Viking II audio circuit.


Title: Re: Viking II Civil Defense version
Post by: kb3rdt on August 13, 2017, 08:22:49 PM
I am thinking doing this mod

http://wireless-girl.com/Projects/AMTransmitters/JohnsonViking2.html



Title: Re: Viking II Civil Defense version
Post by: WO4K on August 14, 2017, 06:27:15 AM
My goal is to bring this puppy back to stock first. I want to find out just how much those factory mods (compression and clipping) affect the audio quality.

I cannot fathom why some DPO (Dreaded...or the "D-word" of your choice...Previous Owner) butchered the stock panel so badly. I have not found anyone who is currently in the business of the restoration of boat anchor panels using the original silk screening process. Even if there was, it would require scanning a good original Viking II CDC panel...and the chances of that are slim.

If anyone out there knows someone who does silk screened panels, please let me know. And if anyone has a spare Viking II CDC panel they want to sell...(I know, I know...odds of winning the PowerBall lottery are probably better).


Title: Re: Viking II Civil Defense version
Post by: k7mdo on August 14, 2017, 07:04:09 AM
I have and operate a CD version that is currently "bone" stock. Good solid transmitter but the locals refer to the audio as 'a little thin'.

That said, I have contemplated many of the mods to enhance the audio and modulator section but always seem to get sidetracked with less daunting projects.

As to the panel finish, mine is pretty bad with paint failure.  The paints used were fleeting at best.

One thing to note is that there are at least two versions of panels.  Mine is not a CDC version but rather a CD version on the original front panel. It is part of the logo and clearly original.

If you do find someone who can duplicate with silk screen you will want to specify, if possible, the wording.

At this time I have two non-CD panels from donor Viking II transmitters and numerous parts should you run into parts issues with your restoration. 

Interestingly between the three Vikings I have, at least one has a different meter hole size in the panel, so there are variations you might not at first suspect.

I find the transmitters easy to work on but often I find issues crop up just from the age of the simple things like wire insulation deterioration.

Please let me know if you find a panel restorer who can tackle the CD or CDC panels at a reasonable price!!.

73 Tom



Title: Re: Viking II Civil Defense version
Post by: WD5JKO on August 14, 2017, 07:20:19 AM

      Last year I had my Viking I front panel redone.  Joe, N2CJF did it, and the results came out very nice.

Jim
Wd5JKO


Title: Re: Viking II Civil Defense version
Post by: KA0HCP on August 14, 2017, 02:21:37 PM
modified.


Title: Re: Viking II Civil Defense version
Post by: Pete, WA2CWA on August 14, 2017, 03:30:40 PM
The Viking II CDC had continuous frequency coverage from 1.7 to 30 MHz along with other additions and "CD conform enhancements". The "regular" Viking II did not. It's conceivable that back in the "good old days" rigs were used in Civil Defense setups and "CD Stickers" were put on them. Didn't necessarily mean they conformed to the FCDA requirements. 

See the attached for the Viking II CDC Design file requirements.


Title: Re: Viking II Civil Defense version
Post by: Steve - K4HX on August 14, 2017, 08:29:32 PM
Same crappy audio at the civilian version with the addition of a clipper to make it even more crappy. The only good addition was PTT.


Title: Re: Viking II Civil Defense version
Post by: Pete, WA2CWA on August 14, 2017, 09:03:23 PM
Same crappy audio at the civilian version with the addition of a clipper to make it even more crappy. The only good addition was PTT.

Maybe they felt that if the big bomb went off, crappy audio would make it through the EMP pulse better then Hi-Fi audio  ;D


Title: Re: Viking II Civil Defense version
Post by: DMOD on August 14, 2017, 10:42:01 PM
From my article linked above, check and see if there is an additional coil, L70, in the Pi-Net circuit to determine if this is truly a Viking II-CDC:

Quote
...There are added inductance values at various stages. L4, the oscillator coil, and L5A, the buffer coil, have slightly different inductances with respect to the stock Viking II. An additional inductance in the PI-Net, L70, which has the same value as L10, was added to increase the inductance for an additional 100 kHz slide down to 1.7 MHz...


Phil - AC0OB


Title: Re: Viking II Civil Defense version
Post by: k7mdo on August 14, 2017, 11:49:09 PM
Oddly I have seen both panels, clearly scripted as viking II-CD or viking II-CDC

I imagine it is different years of panel production but can't prove that.  From a circuit standpoint, my -CD version is the same as the ones emblazoned with -CDC.

The stickers are a different issue as I have seen variations probably depending on distribution years and locations.

What I have read is that the restricted audio chain was done so as to preserve intelligibility when a civilian is screaming "nuclear blast!!!!!" into the microphone.

T



Title: Re: Viking II Civil Defense version
Post by: Pete, WA2CWA on August 15, 2017, 02:18:38 AM
Oddly I have seen both panels, clearly scripted as viking II-CD or viking II-CDC

I imagine it is different years of panel production but can't prove that.  From a circuit standpoint, my -CD version is the same as the ones emblazoned with -CDC.

The stickers are a different issue as I have seen variations probably depending on distribution years and locations.

What I have read is that the restricted audio chain was done so as to preserve intelligibility when a civilian is screaming "nuclear blast!!!!!" into the microphone.

T

Where on the panel is it scripted as a Viking II-CD? All Viking II-CDC's had only the "CD" logo on the upper left of the front panel. Same area as the vernier knob is located in the initial post.


Title: Re: Viking II Civil Defense version
Post by: k7mdo on August 15, 2017, 03:32:47 PM
Attached is a photo of my Viking II CD version.  It is not the first I have seen with this logo but have never seen a reference to different logos.  I have seen several with the logo "Johnson Viking II - CDC".

73, Tom


Title: Re: Viking II Civil Defense version
Post by: Steve - K4HX on August 15, 2017, 06:59:54 PM
I've never seen one study showing distorted, under-modulated audio makes it through anything better than non-distorted, fully-modulated audio. But if an atomic bomb went off, it wouldn't have mattered anyway. :-(

Same crappy audio at the civilian version with the addition of a clipper to make it even more crappy. The only good addition was PTT.

Maybe they felt that if the big bomb went off, crappy audio would make it through the EMP pulse better then Hi-Fi audio  ;D


Title: Re: Viking II Civil Defense version
Post by: WD8BIL on August 16, 2017, 12:53:24 PM
Quote
Attached is a photo of my Viking II CD version.

Exact same artwork that was on the one I had Tom.  Seems the "All Viking II-CDC's had only the "CD" logo on the upper left of the front panel." statement is in error!


Title: Re: Viking II Civil Defense version
Post by: Pete, WA2CWA on August 16, 2017, 02:08:28 PM
Quote
Attached is a photo of my Viking II CD version.

Exact same artwork that was on the one I had Tom.  Seems the "All Viking II-CDC's had only the "CD" logo on the upper left of the front panel." statement is in error!

All the ones I've seen and owned over the years had Johnson Viking II-CDC  printed over the plate tank tuning dial and the CD decal on the upper left. This is also what the brochure showed. In the picture below, you can see where the CD decal was removed on this Viking II-CDC.
Bottom line, "who cares"; Johnson only made three versions of the Viking II. The consumer version in kit form, the consumer version in factory wired form, and a Civil Defense version in only factory wired form (which obviously had front panel logo printed with either "CD" or "CDC").

(http://sciencestockimages.com/ebay/092315stuff/johnsonviking-a.JPG)


Title: Re: Viking II Civil Defense version
Post by: DMOD on August 19, 2017, 10:28:16 AM
Here is my Viking II-CDC on the bench after all upgrades were made.

Any other emblems or stickers were added after receipt of the unit.

Phil


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