How to properly tune ranger 2

[kc2etm]

Can some please clarify dipping the plate as the tuning procedure says for my ranger 2
I was under the impression this means tune the final to the lowest reading on the ma meter
But when I do this I have low output and scratchy audio its lowest point is about 60 ma
But if adjust it to 135 ma it has close to the rated output and clear audio
Is the first procedure correct or should I just run it at 135ma?

 on the lower bands the lowest reading on the meter falls right at 135ma is this normal is it my operator error or should the upper bands fall there to?

[W3GMS]

It sounds like your doing it correctly.  To resonate the final you tune for minimum plate current.  Then you increase the loading until the plate current starts to rise.  As your doing this, continue to re-dip while increasing the loading until you get a dip at the rated plate current that is suggested. 

As far as you audio distortion at these very low plate current levels, keep in mind that it will take a lot less audio to modulate the final at the very low value of plate current since you running far less power.  The other disadvantage is that the modulation transformer is mismatched at these low plate current levels.  Final plate Impedance =Plate V/Plate Current.   

Joe, GMS   

[kc2etm]

So then as I thought the higher bands are not working correctly because with aux coupling fully advanced to 7 the lowest dip only falls at 60 ma not 135ma which I believe is due to the fact of low grid current on the upper bands can not get more then 2 ma grid someone told me there was nothing wrong that I was just tuning it wrong

[WQ9E]

Two mils is sufficient to drive the Ranger 2 to normal plate current and is the recommended amount.  Where is the main coupling control set?

Are you using either a good dummy load or a matched antenna?  A significant mismatch will prevent reaching full input.

How much grid drive are you using to reach rated input on the lower bands?  Does it take more than 2 mils?  If so then you may have a weak final tube or a problem with the clamper tube circuit.  As I recall the clamper circuit isn't adjustable in the Ranger like it is in the Valiant but if a component shifted value then the clamper may be reducing the screen voltage at normal drive levels requiring excessive grid excitation to turn off the clamper.

[kc2etm]

Lower bands I can get grid drive full scale I get 2 mils at number 2 on the drive control on upper bands I Max out at 2 mils with drive control all the way up main coupling I usally set to what the book says for the band 80 160 and 40 all work correct plenty of grid full scale

[W3GMS]

Lower bands I can get grid drive full scale I get 2 mils at number 2 on the drive control on upper bands I Max out at 2 mils with drive control all the way up main coupling I usally set to what the book says for the band 80 160 and 40 all work correct plenty of grid full scale

Try to keep the grid drive at 2.5MA for a single 6146.  You should never run full scale grid drive on a single tube.  The manual explains all of this and you mentioned that you have the book.  As Rodger has stated, 2 MA of grid drive is not your problem and to prove that to yourself, reduce the grid drive to 2 MA on the lower bands and you will find that you will still  have the same output power. 

Maybe I am misunderstanding on what your trying to say.  Most of your post are one long sentence  .

Rodger has given you some excellent advice in his post to you. 

Joe, W3GMS 

[kc2etm]

I do keep it at 2.5 when running but i have turned it up just to see the different amount between the lower and upper bands full scale lower and tops out at 2 on upper bands
I have box full of 6146 so I wasn't worried about the tube and it was up down less then a second just for comparison.

[kc2etm]

I guess the main issue is when dipping the final on the upper bands the plate current ends up at around 60 mils  i thought this was because of weak grid current but if 2 is enough i was mistaken.
 on the lower bands following the procedure in the book the plate current ends up resting near 135 as the book states it should

[wa3dsp]

The Ranger will confuse you a bit if you are use to other rigs without clamp tubes. On the Ranger if you drop the grid current below 2 ma or turn it off all together the clamp tube will reduce the final screen voltage and the plate current will go down. On a non clamp tube type transmitter the plate current would max out under the same conditions.

Some one asked you what you are loading into? A dummy load? Hopefully that is what you are using for testing but from what you are saying it is doing maybe not. Use a dummy load!

It is normal for the Ranger to have lower drive as you go up the bands. You compensate for that with the drive control. So the control might be turned way down on 160 or 80 and all the way up on 10 meters. As long as you get a minimum of 2ma it should be OK. Normal grid current is about 2.5ma but 2ma should give decent output on the upper bands. Depending on your line voltage you should get 40-50 watts output on 40 meters and below and I would say at least 30-40 on the bands above that.

I think you said this rig was significantly mod'ed. Do you have a schematic of the mods?

What version 6146 are you using?  6146, 6146A, 6146B ?

You should carefully measure the screen voltage on the 6146 final under load at full output to make sure it is not being clamped. It should be 150-170 volts. Less than that might be your problem. Pin 3 G2.

[kc2etm]

I have measured the voltage at the final and it is just about 170 on the lower bands upper band are only about  50 volts so it does seem to be getting clamped but why only on the upper bands unless the 2ma indication on the meter is wrong and it's lower
I get about 40 watts on lower bands and about 20 watts upper bands so that may be normal but i have the low plate reading on the upper bands when I run it like that it is scratchy and distorted if I turn the final away from the dip to raise the plate to 135 it clears up I usally set the couplings according to manuals suggestion and go from there but I have the same results in all positions

I have been using a dummy load for testing and i have tried it on air with known good 10 meter stick

[Pete, WA2CWA]

if I turn the final away from the dip to raise the plate to 135

If you keep doing this, you're on your way to final tube destruction and/or final tank circuit problems.

[kc2etm]

Ok so I found a broken resistor r25 3 ohm off v3 pin 1 changed and its working properly now so my new problem I want to run with an n3zi dds vfo which I just tried with the buffer amp he shows on his site here http://www.pongrance.com/dds-buffer.html feeding to the x1 crystal position and the radio exhibits similar behavior as it did with the broken resistor
do you think that it is because the dds vfo is to weak is there a better point to tie the external vfo into also how much vfo drive do I need his plans says it should be outputting 5v p-p do I need more?

[wa3dsp]

I don't have any direct experience with the VFO you are using but in looking at the specs for two commonly used VFO's, the Heath HG10 and the Johnson 122 it looks like 5-8 volts PP output is a good number, so if you are truly getting 5V PP under load I think it should work.

I haven't looked at the schematic but if I were planning to use a digital VFO with my Ranger I would probably put an RCA connector on the back panel and wire it directly in as a VFO input the way the internal analog VFO is wired using one of the xtal switch positions.

[kc2etm]

Ok so I built a different buffer amp for the dds vfo now it to loads properly on the upper bands I guess it wasn't enough drive now the problem I'm seeing is lower bands can easily break 100percent mod as seen on my scope and on a powered peak meter upper bands can not break 50 percent mod when this all started I had burned a small choke at the base of the main plate choke I read somewhere that it was a 4.0microhenry choke for filtering VHF
I had none so I tried to make one with a 47k resistor with 4 turns of wire around it do you think this part I made could be causing it also if it is can I safely just make a jumper for that instead

[wa3dsp]

Are you talking about the choke right off the plate cap of the 6146? If so it is a parasitic choke to eliminate higher frequency parasitic oscillations. It is necessary. It would have nothing to do with modulation.

[kc2etm]

No at the base of the large choke see picture also it seems only 10 and 15 are doing all other bands easily reach over 100 percent mod

[wa3dsp]

OK, I am too lazy to look at the schematic but it looks like a 47uh choke? In any event if it is not opened, and if you are getting Plate current it is not then leave it alone. It is just further RF decoupling. The big choke takes care of 99% of the decoupling. This was added for additional RF filtering. Many rigs do not have it. You could bypass it but if it is not open I would leave it alone. It would not have anything to do with modulation or power output.

[kc2etm]

Ok thanks it was burned open so I will leave the part I replaced it with and move on
Any ideas where to start looking for this 10 15 meter modulation issue


Thanks
Fred

[kc2etm]

well i found 4 more bad resistors and two 150 ohm resistors feeding the grids of the 6l34 tubes one was 100ohm and the other was 250 ohm change all these and the modulation is back on the upper bands so my last question is this radio was modified alot by the last owner it has an xlr in which i use with the audio equipment an rca to key it but it also has a 1.4" mono plug i dont know what that could be i tested voltage and it had about 70 volts ac on the tip pin any ideas what this may be it looks to feed into the audio section but its hard to tell the wires are to burried to see this a cw key jack maybe?

i can post up some pictures if it will help

[W3RSW]

 -Very tedious reading OM.  Perhaps a T/R line.  See if it's same voltage in standby or if keyed and unkeyed voltage stays the same.

Also I think an Ohmite Z50 might be nice for where you placed a homemade substitute below the RF choke in the B+ line.