NEW Project - 6146B Plate modulated by Hammond 1628SEA and 85W SS Amp

[K1JJ]

Thanks for the suggestions, guys!

Yes, I like the idea of continuing the brass to the sides.  The Collins 32V series does it too.  I am out of brass material, but there are excellent gold pin stripes available in the same 3/8" width I could use. I might also add a border around the whole panel using  1/4" width pin striping with curved corners....  All this can be done later after I paint the panel slate blue and the middle dark blue as shown.  

I am stuck about what to use for lettering. I don't want to go with engraving the panel or a silkscreen.  But I'm game to find a transparent stick-on lettering that comes in black or white to cover the two shades of color.

I saw some cool gold anodized aluminum knobs, but decided to go with some all black, 2" knobs.  The nameplate will probably be gold brass with the engraved "Commando" as shown.  So the main focus of the panel will be the middle window 6146B tubes with the gold bezel frame and thumb knobs. The panel will start to look busier once I start mounting the controls, big knobs, switches, meters, etc.

Any suggestions appreciated before I start the sanding and painting process. [You probably didn't know that I was once an auto body apprentice for a summer back in 1970...]  

T

[w8khk]

I use the P-Touch labeling system for my transmitter panels.  Clear with either white or black lettering, like you mentioned above.  Various font sized available, very easy to produce and apply to the panel, inexpensive media, and the P-Touch machine is around a Benjamin, give or take.

[K1JJ]

Hi Rick,

Good idea on the label machine. One of the local hams offered to print me out some black or white transparent labels.  That should work FB.

We're just about decided on the panel colors and style.  I found that different top and bottom colors make the rig look like a junk yard car with different colored doors.  I also found that curved lines and colors do not go well with square panels.  The Ranger has curved panel edges which makes its curved colors work.  This square panel needs squared color borders.

 I like the dark slate blue (or sky blue) along with the dark blue center and added gold horizontal 3/8" thick pinstripe following the brass to the panel edges.

I plan to add 3/8" gold pinstriping around the rectangular DDS window to kinda match the 6146B window..  That thin gold pinstripe will be the same thickness as the brass.

There will be a lot of black knobs and black meters added to better balance the overall bright paint.

Here's some samples. I am favoring the light blue top and bottom or maybe the dark slate blue.  (2nd picture)

They have etching primer for aluminum at NAPA stores.  Almost ready to sand and prime.

Any ideas?

T

[w8khk]

All the color schemes look good to me, but of course it is a matter of personal preference. 

The black-lettered  P-Touch clear labels will view nicely on the lighter sections of the panel, while the white labels will contrast well on the darker areas.  In-between panel lightness or darkness may be problematic, with either the white or black lettering providing marginal contrast. 

With good lighting, either may work ok.  But with older eyes, sufficient contrast is your friend.

My experience is limited to black lettering on natural aluminum, and white lettering on black wrinkle panels.  Some trial and error with the labels may help to achieve the desired results.

[WD8BIL]

Real men don't label!!!

Checkout the Four Horsemen!  

[K1JJ]

Real men don't label!!!
Checkout the Four Horsemen!  

FB!

It all depends on how many knobs, switches and meters you have -  and how good is thy memory...  

T

[WD8BIL]

Ya gots a point there Fabio! We ain't gettin' no younger. Memory is the first to go.....I think.

[w8khk]

Real men don't label!!!

Yup!  That's why the RME-69 receivers never had any labels on the controls.  They felt the ham should just know how to operate the receiver.  But labels on transmitters are helpful when you have guest operators in the shack.    I am sure Tom will be hosting a few Pharties!  

And if you have labels, they should look good!  I never had the patience to do fancy paint jobs like Tom does.

[w8khk]

Ya gots a point there Fabio! We ain't gettin' no younger. Memory is the first to go.....I think.

Turning 75, I realize I really miss three things that I have lost.  First, my mind.  Second, my memory.  What was the third thing?  I just can't recall???

[N4LTA]

Still waiting for all the parts to arrive. Have received the SEA1628 transformer , the 85 watt amp, the band switch, sockets and variable caps. Waiting on the roller inductor, the main chassis and panel, the 85 watt power supply transformer and power supply parts. Hopefully, all will be here this week.

The front and rear panels are almost ready to send for laser cutting. That wont take long but it needs to be right.

Look forward to really getting started.

Pat
N4LTA

[K1JJ]

Hi Rick,

The painting ain't so bad, in fact kinda fun if you make it the first step before mounting parts. Once done, it's a joy to see it all come to life with parts mounted.  The lettering comes last, once everything is working.  Also, a painted panel with no obstructions looks cleaner since the panel screws are shiny and not painted.  I sanded, cleaned, sanded again and cleaned the panel well.  Prep is the key.  Keeping the dust out is also important.   I am going to use a satin finish for the slate and a gloss for the navy blue.

This panel will now get baked so that the etched primer can handle the taping without peeling -  required to paint the next two colors, the slate blue and the glossy navy blue bands. I figger the window area should grab all the attention with the gold and gloss.

BTW, that black monster on the wall is the acoustic enclosure for the big step start. The contactors inside are extremely loud on start up.

I'm having these obscene thoughts of adding a 3rd 6146B in case I decide to upgrade to a big Hammond 1642SE xmfr later on. I have the tube sitting there on the chassis just calling me to cut the hole. I could always just wire it for three and unplug one, leaving two with no bad effects if desired.  The window lets me view three tubes.  This would be a very compact Valiant class TX.  The big Hammond wud fit underneath that 6" high chassis.  Just thinking...

T

Primer Etched Aluminum and Drying:

[W1ITT]

Tom...
It's great fun vicariously observing the development and progress of your latest rig.  I was going to keep my trap shut, but when you mentioned the third 6146 it made me throw my vote in for it.  Early on in this series, when you had the mockup with a single 6146 in front of all that iron on the chassis, all I could think of was that fellow standing in front of the tank in Tiananmen Square.  Just one 6146 looks brave, but lonely.
73 de Norm W1ITT

[K1JJ]

Still waiting for all the parts to arrive. Have received the SEA1628 transformer , the 85 watt amp, the band switch, sockets and variable caps. Waiting on the roller inductor, the main chassis and panel, the 85 watt power supply transformer and power supply parts. Hopefully, all will be here this week.

The front and rear panels are almost ready to send for laser cutting. That wont take long but it needs to be right.

Look forward to really getting started.

Pat
N4LTA

Sounds like a well organized plan, Pat!  The fact you are ordering so many parts, new chassis, new panel, etc., tells me it will be a nice looking rig.  The laser cut panel both front and back oughta look FB.  Did you decide on colors and panel "decorations?"  I really like the gold brass. It's put the rig into a different class. The two-tone Earl Shieb paint job is new for me too.

Norm:   FB on the lonely 6146B...    Two looks a lot better and three makes it a bigger rig. I was thinking of running the voltage down low, like 400VDC, low impedance and three tubes would have a lot of modulation headroom potential running at  80 watts or so.  I just don't know how much the Hammonds will take without saturating. Also, I want to keep the HV down for transformer longevity. The 1628SEA is hi-pot tested at 2KV and the 1642SE is hi-pot tested at 3.5 KV.    So there is some room to play.

But as I said, I can always just unplug a tube or two until it is a good lashup.  I'd give it a 50-50 chance of becoming three tubes at this point.  

T

[K1JJ]

Update:

The good news:  I added another 6146B for a total of three in a triangle.  I plan to boost the TDA 7294 audio module input voltage from +- 35V VAC up to +- 40VAC, data sheet maximum.    I plan to initially run the three 6146Bs  at a lower voltage (maybe 400-500V)  to have ample independent modulation voltage available from the module and transformer output.   I can always unplug tubes to experiment and see what the rig likes best.

I checked the volume in cubic inches of a Johnson Valiant - and "Commando"  is about the same displacement, but has more room to spare, especially underneath the big chassis..  The Valiant weighs 78 pounds and I'm sure Commando's fighting weight will come in much lighter.

Not-so-good news:   I painted the next panel coat. (slate blue)   I let the spraying get away from me and created a paint run. Too aggressive.  I should have used lighter coats.  Now I gots to sand it down and start over... [sigh]    It does look FB, despite the run, however.   It's best to take your time and use very light coats, especially if the humidity is high or the temp is not 72 degrees ideal.

T

** Second Update:  Panel sanded down and repainted. Whole panel now slate blue, satin finish. Looks beautius, no runs.  Next, let it bake on the coal stove for a night and then add the glossy Navy Blue center section tmw.



Pic Below: The Commando is cooking...    (Those heatsinks really work!)

[N4LTA]

Tom

Looks great. What is the size of the digital VFO cutout'? Is it a readily available digital VFO?

Thanks

Pat

[W1RKW]

.... The Valiant weighs 78 pounds and I'm sure Commando's fighting weight will come in much lighter

Commando will float like a butterfly and sting like a bee.

[K1JJ]

Tom

Looks great. What is the size of the digital VFO cutout'? Is it a readily available digital VFO?

Thanks

Pat

Hi Pat,

My DDS is an older one that is not made anymore.  There are plenty of them on eBay that you should be able to find and cut a custom hole.  I may choose to use my main station DDS as a driver and fill the panel with a simple frequency counter that will sample the final output and display a bright set of blue digits to match the panel artwork.  

I decided to go with a "wildflower blue,"  my favorite color for panels here. I found the slate blue to be too bland. The new blue is striking in sunlight and I'm happy.  I'll be mounting parts as soon as this dries.

I ordered some 3/8" gold chrome pin striping. This will extend the brass window to the panel edges and also make a window frame for the DDS/counter.  Once finished, I'm hoping Commando to be the best looking rig in the shack, caw mawn.


Bob:  Yep, with three 6146Bs, Commando is well equipped. Maybe a decal of Schwarzenegger's macho face just above the nameplate is in order?

T


Commando panel baking on the coal stove:

Available Commando decals:

[w9jsw]

Can you jot down the amp circuit you use for the dds to drive the input LC circuit?

[K1JJ]

Can you jot down the amp circuit you use for the dds to drive the input LC circuit?

Hi John,

It's been over 10 years since I built it, so was foggy... I looked inside my RF DDS driver and realized that the DDS is actually driving a 200 mW to 5 watt RF amplifier costing only $20 made by a hobbyist QRP company. (16 dB gain)    I used a 11N90 after that, but it is not really suited for the job at that low level. For even more output, then there are bigger and better linear boards like this available.

5W amplifier:
http://shop.qrp-labs.com/pa


Ton of kits:
http://shop.qrp-labs.com/kits


This little SS linear amp should give you ample drive for a 6146 style rig.

They also carry a digital vfo/sig gen.  Something like this may be what you need.  

* Anyone who comes up with an "amplified power DDS" design based on current parts or boards, let us know!*


T

[K1JJ]

Now it's the fun part - just like assembling a Heathkit!  Most of the drilling and blasting is done.  

I ordered some big 2" rubber feet. Commando will be sitting pretty.     Most of the parts will be bolted on by tomorrow.  The wiring will be the next big push, followed by testing.

Do ya think the tank components are big enuff to handle three 6146Bs?  

There are a few cosmetic errors, but I'll straighten everything out later on.

The dark blue section will be enclosed with chrome gold pin-striping to match the 3/8" brass. Same with the DDS/freq counter window.

The bandswitch will sit directly over the tank coil for short leads.   There will be long standoffs bolted to the panel to support it.

Lots of iron to load on the back chassis.  The TDA  audio module will have a heatsink on top with a small muffin fan.  The 6146Bs will get some of the air.

The ~1"-2"  holes in the back will hold the sockets for the relays - and the smaller 3/4" holes will hold the 6AQ5 and OB2 screen clamper tubes.

Little by little.

More later.

T

[K1JJ]

Here we go!  Gots most of the parts mounted. We can get a pretty good idea what this puppy is gonna look like.  I haven't weighed it yet, but it might be closer to a Valiant weight now, 78 pounds.  The transformers in the back actually made the chassis stronger due to reinforcement.  Got some nice spinner knobs. Still need to add the gold pin striping around the Navy blue.

I got rid of the big beer can filter caps and went with newer, more compact ones underneath. Notice there is ample space there if I decide to go with the biggest Hammond audio xfmr.  The heatsink is mounted on top as well as the TDA module mounted below. The muffin fan still needs to be added on rubber mounts.

Commando still needs a nameplate. It may be the coolest looking rig in the shack.  Really pleased so far.

T

Pic #3 - glorious!   Commando in the company Titans.  4X1 plate modulated rig on right. 4X1s linear on left.

Pics came out good today for some reason.

[K1JJ]

We talked about having enough room.  Kinda tight on top, but still some room.   Some room to spare underneath.   Panel space pretty filled up except for the center for a nameplate.  Looks like I forgot to mount the toggle on the left. That's a loading padder for 160M.

[K1JJ]

Transformers left to right:  850V CT HV xfmr,  TDA Audio module  xfmr +- 40V,  6.3V fil,  Hammond 1628SEA audio transformer.

The blue freq counter really look trippy when lit. Still room to add a DDS later on.


Have six fuses - well protected.

Still need to mount the spark gaps for the Hammond.

[K1JJ]

Pic 1:  Notice how close the bandswitch is mounted to the tank coil for short leads.

I use 1/4" panel shaft sleeves that keeps the tuning movements rock solid.


#2 pic shows a quite soulful three little 6146Bs backed up by all that heavy iron in the back... 

[K1JJ]

That's a real silver plated coil. Strapping 5/16" edge wound.

Notice the G-76  (Jim / JKO) clamper tubes, OB5, 6AQ5.