The AM Forum

Ok guys,
want to see some mods. in a VV?, this modifications were made maybe 30 years ago, I recieve this rig as a gift from a Ham friend here in Mexico City.

The transmitter dosent works, have some problems in the Low voltage P.S. what should it do with this rig?

Regards to All

Pedro/ XE1YZY

http://www.angelfire.com/electronic2/xe1yzy/Viking/index.album?i=2

Wow!  Someone went loco installing random meters on that poor xmitter!

There's no restoring it unless you get a new front panel.... they show up from time to time on eBay and hamfests.  Other than that it doesn't look too bad.  I guess I'd just get it working, do the standard audio modifications, and enjoy it as is until you find a new front panel.

73 John

Hi John..

Yes a lot of meters, and knobs! but you are right, Im going to get a front panel, and do the standard Modifications, Vikings are great rigs!...

73'S

Saludos!

John, guess what! looks what I found yestarday!

http://www.angelfire.com/electronic2/xe1yzy/viking/index.album?i=0&s=1

" Is better have friends , than have money, isnt? "

Wow!!  Looks like it's in good condition, too, after you clean and wax it a bit.

It sounds like the boatanchor scene in Mexico is the way it was in the US about 10-15 years ago - lots of stuff available cheap.

Now you can sell all those extra meters to pay for the front panel!

73 John

Pedro,
          I can speak for myself and many others on this boards, we'd LOVE the opportunity to do a sked with you sometime! Do you currently have anything up and running on AM, and what are your bands of choice? Also, do you work 75 and 160 meters?

Lately, a few of us have had European and East-West Coast skeds on 160M and 75M. If we can be heard there I think we could be heard in Mexico and visa-versa, with the right antenna and power levels.

Let me know, and the best of luck with your Valiant!

John;
Yes it is, AMers and Boatanchors fans are growing here in Mexico, but still we are not to much people, the rigs are cheap yes , but the parts for fixing the radios are expensive, Im use to buy the supplys from US, but we have to pay for international shippement and the import taxes, so,the people here don't understand sometimes why pay $120 USD (plus taxes) for a new set of 6146's tubes for a viking valiant, if the radio itself dosent cost more than $100 USD!



Joe;

I'll be more than happy too!, yes I have some AM equipment ready!!, another Viking Valiant already fixed with the help of this forum, a Collins 32V3, a R390 and some other receivers ,Im on the way to finish a "cloud warmer"  antenna for 80 meters cuting for 3.885 Mhz.

My problem here is the noise! Mexico city is a HUGE city with a lot of electrical and static noise, its almost impossible work 160M, but I have a little weekend house out of the city, there Im installing a "beverage" for 160M, so Im on the way Joe.

I let you know as soon as I finish my antenna for 80 meters! to make an Sked!

73's

Pedro.

Pedro,
        Many thanks for the quick reply! If possible, before Springtime QRN sets in and produces 20-60 over 9 noise levels please let me know. Either post something on the board or email me at: n3ibx@verizon.net. I know of about 6-12 other 160M ops that would really enjoy a contact with you ie: K1KW,K1JJ,W2PFY,W3SLK,K2WI,K2ORC,WB3HUZ, etc on the East Coast, and Steve, KL7OF in Washington, and others on the West Coast.

I'm usually on 1885KC or 1930KC. I don't know what the Mexican bandplan is for 160M, but would assume it's most likely similar to what it is in the US. Please let me know what frequency or group of frequencies would be best for you when the time comes.

If you can't get your antenna up by this season, there's always next season. We've had good results here on the East Coast talking to the West Coast, and even being heard in Europe.

We've discovered that the higher you have your antenna the better. Also, a minimum power requirement to work good 160M DX seems to be at least 300 watts or so. The more the better. I believe in "Antennas by Eimac" - hi!

Best Regards,
                  Joe Cro N3IBX

Me too Joe!

Im going to fix my antennas this weekend and hope we have good conditions, 160m ist difficult in Mexico city, for the noise but we give us a try!, I'll be more than happy to make a QSO!!

73's

hi,
    a cloud burner won't help you work back east neighbor!  have a way
to switch it. i have 3 ele vertical array aimed back east, it works some
of the time pretty well

73's deano - wa1knx/7 tucson az

Hi Deano...

Yes, the vertical array works better, but I dont have enough space in my lot, maybe for two verticals only, Im going  to read something about vertical arrays, TNX!

Pedro XE1YZY

Hi to all...

Was a rainy weekend in Mexico city, so I decided to start with the restoration of the Valiant, a lot of mods. has been made, so i rip off all the extras and go backwards to the original circuit ( well almost)

Please take a look!

http://www.angelfire.com/electronic2/xe1yzy/Viking/

Saludos!

Pedro, I'm astounded - you've done what looks to be the impossible in only a few short days.  

I love the picture with the stack of "custom features" removed!  At least now you have a bunch of extra meters for homebrew projects!

Great job.  73 John

Thanks John

Yes a lot of extra stuff, there is still a long way to finish the valiant, I want to update both P.S. and make the audio mods. its a fun rig to work with, my idea is a finish with a reliable AM exiter.

Have a nice week!

Pedro

I have torn into a lot of these Johnson BA's and found that the best conversion to Hi-Fi is using an external AF Power Amp and backwards connecting a Hammond Audio output transformer as the Mod Iron and a Hammond choke as the Heising reactor. This stuff fits on the chassis once you remove the OEM modulator. I have tried everything I could with the valiant and if I was going to do it again, that's what I would do. Last wednesday I was at KC2LT's radio shop and watched Chuck, K1KW carefully adjust the Dave's radio for 150-180% positive audio with absolutly smooth response. This really works and is easier then trying to make a silk purse from a sows ear so to speak with the stock iron. I'm sure Dave will give you the part numbers and directions where to get the parts. His e-mail is kc2lt@comcast.net. Actual hook up can be described by most any of us. Give this some serious consideration before you spend a month trying to get the stock iron to sound good.
Keith
WA1HZK

And if you go this route you have the option of leaving everything outboard. Thus, you can leave the internals stock. This will allow you to sell it on eBay in the future as an "unmodified/stock" rig and ask for big bucks. The purists will eat it up!

Keith

I really wants to know about who to hook up an external audio amplifier, can you give some schematics please?

xe1yzy@aol.com

Thanks in advance Keith!

Pedro, I didn't bother with the Heising choke in mine, and I used the stock modulators and modulation transformer.  I removed the modulator driver transformer, replaced it with a 600 ohm to push-pull grids line transformer, and drive that transformer with a Gates broadcast limiter which in turn is driven by an equalizer.  Sounds good to my ears, and is REALLY easy.  Mine will run +125% modulation no problem, even with the stock modulator.  Just load the transmitter for 10% less plate current than is recommended.

KB3AHE does the exact same thing.  It provides headroom for the modulators, keeps the current down on the mod xformer, and allows higher positive modulation peaks.  You can keep the rest of the modulator section stock (just yank out the tubes) if you ever want to go back to the internal mike amp/driver (yuck!)

73 John

Ok Steve...

Well, my other valiant is "unmodified/stock", and I really wants to keep it in that way . even if the 866A are not a great performers , looks great when glow isn't?.

The valiant under restoration have a lot of " extra holes ", so I really like to go and find who far can we go with the mods, now Im working in the acuracy of the original meter, im going to ad some adjust controls, for mesure the mA in the grid and plate circuit.

any way, so far so good!

TNX!

Pedro

I would recommend driving the  grids of the 6146s with an audio amp vice a line level device. The 6146s are running AB2 and will pull grid current on peaks, thus requiring the driver to produce power. The lower the impedance of the driver the better for dynamic regulation resulting in less distortion on the peaks. A typical solid state audio amp will have an output impedance of less than an Ohm. Line output devices are likely to have an output impedance an order of magnitude or more greater.

Are you sayin' I'm DISTORTED, Steve?

Seriously, Steve makes a good point if you're gonna run the Valiant full bore - or even if you're not.  In any case, make sure you use a good quality xformer.

73 John

Great John!

Really sounds very easy! where I can found the 600 ohms transformer and the Gates broadcast limiter?, or what can I use insted the gates device?. is expensive?

I have a spare audio transformer for my HRO 60, pri 10K sec. 8/600ohms @10 Watts, does he works?

Thanks AMigo

I can say with out a doubt YOU are distorted. Otherwise you wouldn't associate with me. Your transmitter is another matter.

Guys...

 Can I coupling the 6146's transformer with this transformer conected backwards?;
 pri. 10K sec. 8/600ohms @10 Watts, its a spare transf. for my HRO 60

 :doubt: please show me the light!

You will need a 100 watt transformer to do it right.
I'm meeting the guy tomorrow who has done it twice. I'll get you the P/N's then.
Keith

100 watts to drive the grids of the 6146s? I hope not.

The  10 watt tranny should be fine. I don't know about the impedance ratio though. JS clip lead it in and see if it works.

I have a spare panel for a Viking Valiant 2. Unfortunately the rig in question looks like a straight up Viking Valiant. Dunno if those panels are interchangeable.

Ok Steve thanks a lot, I have some transformers for " cut and try", smokes its part of the joy isn't?

Hi John...

many thanks,No it is not a Viking II, is a viking valiant,, and Im already have a panel replace , I update the pictures you can see the new panel there.
http://www.angelfire.com/electronic2/xe1yzy/Viking/index.album?i=2
73'S Pedro

Okay, I am glad to see you got the right panel for the transmitter. I saw the pictures, it looks nice.  The Vikings and Valiants make for nice restoration projects.

Regarding the spare panel that I have available should anyone need it I should have been a bit clearer. It's a Valiant 2 panel not a Viking 2 panel. Apparently Johnson made 2 versions of the Valiant over the years. The Valiant and the Valiant 2.  The primary difference between the 2 rigs was the design of the panel. The Valiant 2 front panel was designed to have a more "modern" look for it's time. It's grey and silver with metalic silver trim and brushed aluminum knobs. From what I have been told Valiant 2's  are relatively rare.

Anyway, glad to hear you got the parts you need. Good Luck with the Valiant restoration project.

73's

N2IZE

I hear most of them, along with Viking IIs wound up on the CB band.

Pedro,

I want to give you a slightly different approach to look at. Please click on this link and notice the modification that Gary W3AM made to his Viking Ranger. It is taken from the Ranger modifications originally documented by Tim WA1HLR.

http://www.w3am.com/ranger.html

In this change, the driver transformer is eliminated entirely. I have found that most of the limitations in both the Ranger and the Valiant center around this transformer. The phase inverter circuit, suggested in the diagram shown on this page, has worked very well for me. It eliminates the fidelity restrictions imposed by the orginal driver transformer.

It is so simple and requires but a very few inexpensive parts. In both my Ranger and in my Valiant I use this same circuit, one half of the 12AU7 as a phase inverter and the first half as a voltage amplifier, preceeding the phase inverter. I feed line level audio into a UTC A-11 transformer, which matches the balanced line level audio from my audio equipment into the grid of the first half of the 12AU7. I also mix audio from the microphone preamp in at this point. The old clipping coltrol is line input gain and the old audio pot is the microphone gain. You can choose one or both audio sources this way.

If you choose to try this circuit there is one caveat! When you wire in the voltage to the plate of the phase inverter, you must find another source of HV for that tube. In the Valiant, the HV is switched off and on (transmit to receive) and in doing so the coupling caps to the grids have to charge, causing a very heavy mod current spike. I believe that I tied it to the low B+ (380 volts) and that worked fine.

The 6146's are biased to run in AB1 and provide plently of audio for the finals. For a while I removed one of the 6146's from the finals, making it a pair modulating a pair. I was concerned mostly with the heat and the extra loads placed on the transformers by running it where Johnson wanted it run. By removing that tube and solid stating the power supplies, a lot of heat was eliminated.

Later I put the extra 6146 final back in and it's fine that way too but I still only loaded it to about 230 ma. This gave me 105 watts of nicely modulated RF out. I loaded it heavier to test it and still could modulate it well but not with the reserves that gave me good asymetrical positive peaks at the lower power settings. I doubt that anyone that listened to the Valiant could tell that it wasn't running the full 145 watts .. the difference was not important.

The Valiant mod iron suffers from the same characteristics as the Ranger's in that the waveform starts to show funny lumps and bumps below 150 hz. The mod transformer is not the best but it does sound real good and works fine. I generally roll off audio under 200 hz anyway.

This mod has worked very well for me. I used this phase inverter circuit on an Apache also and it also sounded very nice. In this case it was a pair of EL34's instead of 6146's (slight different bias settings) being the only difference. In fact, I use EL34's in my Ranger too but the same phase inverter circuit.

Best wishes on your restoration, no matter which way you choose to do it, I am sure it will sound great!

--Larry W8ER

Sadly that is true. A lot of them wound up in the hands of CB'ers who didn't know what the heck they were doing with them. Many years ago someone gave me a basket case Viking 2 that was in very sad shape.  I wound up using it for parts.

Hey, thanks for running this by here on the board. I have a  Valiant that I am working on right now and I might wind up putting some of those idfeas to work.

I'd say this is true of just about every 50's vintage plate modulated AM rig. Nearly all of them used a severely undersized driver transformer in concert with a single-ended Class A driver tube. This was a good recipe for saturation of the driver transformer and lots of distortion. There was some logic in using the tranny on the rigs with Class AB2 modulators. But in rigs like the Ranger where the modulators could easily be run AB1, the transformer made no sense.

Getting rid of the single-ended driver system is almost universally a good thing. Getting rid of driver iron is too. For detailed instructions on how to install a nice phase-splitter driver for the Valiant, see the link below.

http://www.amwindow.org/tech/htm/valiant/valiantmods.htm

Hi Larry

Thanks a lot for your comments and the information, Gary's circuit looks great, I guess is exactly what im looking for my Viking's,actually I have 2 Valiants and one Viking II, so this information are very valuable. one think I likes is the fact that this circuit dosen't needs any sophisticated part. well, for the moment Im working in the P.S. and the VFO, I want a steady voltage and steady frecuency control, by the way Tim WA1HLR, have some very good ideas about VFO improving also.

Many Thanks Larry,  Nice Avatar!

Steve...

Im also saw the vikings used as a CB, and as a CB amplifiers, of course there is also ilegal in Mexico, but even today, among the CB operators , you can find  a FT-1000 as a CB station!