W1IA's GS35 Amp progress

[KA2QFX]

Lots of progress recently...
Worth a look.http://home.comcast.net/~w1ia/new_page_8.htm

[WA1GFZ]

I think your plate suppressors have too much inductance but better too much than not enough.
I bet you could get away with 1 turn with that tight layout.

RG141 as an output lead. I would think you would need RG393.
Now fire that mother up.

I started silver plating tank components with my brother. I quickly found I could do the same thing at home so bought the chemicals I needed from him.
Now I can even plate hardware. 

[KA2QFX]

That's RG-142, a little heavier than 141.  It should handle the power better than RG8X and I've seen that survive heavy QRO.  Technically it should be heavier, we may upgrade it before going full strap.

The chokes are 1uH exactly, with 50 ohms in parallel.  According to Timmy we shouldn't need them at all.   They're wound from Nichrome strap for that warm glow when things go bad. LOL.

[KA2QFX]

Frank,
If you could post something, I'd like to know what you're doing for plating. I used to use my exhausted darkroom hypo and a silver dollar anode. That was WAY too many years ago.  Worked OK. 

[KM1H]

That nichrome will glow especially on 10M if you go that high and 2-3T of copper strap is fine otherwise. Send the nichrome to that nut case Measures.

RG-142 will handle all the power those tubes are capable of on HF. I use it everywhere.

http://www.therfc.com/powerrat.htm

Carl

[WA1GFZ]

My Brother is a Jeweler and bought an electroplating kit from Gesswein. The silver plating solution is EarthGold Silver Plating Solution #210-0942. (www.gesswein.com) Cyanide free, ecologically Safe. It took 3 to 4 volts at a couple amps to plate copper straps. It took about 2 minutes to lay down enough silver to cover the copper.
He gave me a hunk of silver to use as an electrode as to not deplete the solution.
It seemed to work because it became pitted after a while.
He also gave me this cool electroplating cleaner powder than mixes with water.
That took about 6 volts to work and it really cleaned well. At first we were putting a nickle flash on the copper but decided to bag it after a while.
He never uses silver plate so he was happy to sell me the quart of solution and all the other stuff I needed.

[WA1GFZ]

I think 1uH suppressors are way too high. Consider the inductance of the tank coil on 10 and 15 meters. It will also de-Q the tank on the higher bands with the resistor across the inductor. I agree with Carl you will be able to toast your pop tarts on that heater. I think I had 1 turn of 1/2 inch wide brass strap 3/4 inch ID in parallel with 4 2 watt resistors in the big rig before and it was stable 80M through 10M.  It should work for you on the low bands so it is safe for now. When it looks stable try taking off 1T at a time. This will allow even shorter connections to the plate tune cap.

[KA2QFX]

I agree on the suppressors too. They were assembled with 4-40 hardware to be easily modified.  I would prefer to end up with a 1 1/2" "U" shaped loop. Approximately 0.1 -.15 uH.  I think the resistors would smoke well before we dropped enough voltage across the inductors to heat them up.  But it would be amusing. 

Carl,
There's no significance to the nichrome except we had it laying around, and it looks nice.  Does Rick Measures really recommend nichrome for such things?  It does make good meter shunts though.

[Opcom]

That is a very impressive knob on the front panel. It gives the appearance of thickness. Really a very fine job on that amp!

[KD6VXI]

Rich still preaches NiChr.

To be fair, I put it in my 4CX5000, and have NEVER had a problem with it taking off.  I bought it from Rich, made for my application.

Since then, I've gone to making my own with a hairpin shunted by R.

--Shane
KD6VXI

[KM1H]

Rich still believes in the tooth fairy and that parasitics are the cause of all tank circuit and tube arcs. At least JI had it half right.

The Drake amp suppressors are a good example of strap wound; B&W/Viewstar also did that with the PT-2500A.

[K1JJ]

Nice job, OMs!

That's quite a determined, ass-kicking expression, Tina.  If I'm in the DX window and you break in with that beast, ah ah ah... I gotta go - just gots a phone call...  

T

[KA2QFX]

I went and reviewed Measure's recommendations and anecdotes on parasitic suppression and can't find much to argue with in that regard.  However, I did some further reading into his multi-part QST article on amplifiers.  When I got to the part on IMD testing using a generic SSB receiver and a harmonica I had to rethink a few things.

I mean, here I am winding hybrid combiners so my sig jennys don't interact and all I needed was a Hohner?  Who would have thunk it. LOL...

Mark

[Steve - K4HX]

Quite a few PC sig gen programs will do the two-tone thing. No hybrids needed.

[KM1H]

I went and reviewed Measure's recommendations and anecdotes on parasitic suppression

It was long after that article that he got some bad acid and got kicked off several forums with his voodoo science.

If you want an earful call Eimac and ask about him

[KA2QFX]

Quite a few PC sig gen programs will do the two-tone thing. No hybrids needed.

I'm not combining audio to modulate an exciter. I'm combining exciter RF from two very clean exciters. It's the cleanest way to get really good IMD measurments. I'm winding a new combiner because it needs to handle a little more than milliwatt power. Camawn.

Afterward maybe I can use it to broadcast ISB   LOL.

[Steve - K4HX]

Got it. Quite different. Good luck.

[W1IA]

Nice job, OMs!

That's quite a determined, ass-kicking expression, Tina.  If I'm in the DX window and you break in with that beast, ah ah ah... I gotta go - just gots a phone call...  

T

That will be the day Tom....AT least with the array and that monster I will place in the top 10? You will have to match with Chuckles!! I wonder what he has in store for 75?

Just a couple of copper straps to make and adjustments to the suppresors and it time to ramp up the variac. By late next week it may be making power?

Thanks George for the nice chrome wire covers for the tube vents...SWEEEEET!

[KA2QFX]

Just a couple of copper straps to make and adjustments to the suppresors and it time to ramp up the variac. By late next week it may be making power?

... making power? Don't you mean smoke?   Remember the first time the PS came on-line? 

[W2VW]

This is a good time to remember there's no reason to poke around inside an amplifier like this one with B+ active.

Use handcuffs across the filter bank too.