The AM Forum

   I may get a NCL-2000 AMP, I would like to use this amp on AM, it is supposed to be rated at 300 watts on AM as per the manual. I would use a Viking Ranger as an exciter and have a 3 Db attenuator if needed.

   I would appreciate opinions as to the suitability of the amp for AM, thanks.....


                                              Tom  W6TOM 

It says 300. I usually run mine at 200W carrier maximum. It will do about 1000W on AM peaks but those with newer tubes may do better. I get the impression the power supply is being pushed with AM operation. I also get the impression that it takes very careful tuning to get the maximum from it. It is a nice set requiring little drive. Watch the screen current when tuning up, the 8122 tubes are sensitive to it and costly.

Used one for a couple years mostly on the WFD net with short xmissions.
Worked ok at 300 and change carrier out.
Using a Ranger through an RF pad is one of the worst ways to go QRO.
Way better off doing the low power mod at the rear accessory plug.
Guys under loading and using pads need to hit the books.

Ive been running the NCL-2000 as an AM linear since the 60's when I was on the design team and havent smoked anything yet. The worst thats happened is a slight warping of the tank coil ribs and that took ages to show and hasnt got worse

As mentioned 300-350W is fine as the amp has a very efficient cooling system. Just make sure the tube fins and impleller blades are kept clean.

Always leave the multimeter in the screen position and if you get into windbag mode Id suggest a muffin fan for the transformer and bleeder resistors.

Carl

I have an old add here that says 10 to 200 watts input.  If that is true you wont need the attenuator.  Maybe Carl can chime in on that one!

When and where can we hear you and your equipment on AM Carl?

 I was not aware that there was a low power mod for the Ranger. What drive level were you guys using to get 300 watts of carrier??

 The 3 Db pad was suggested by another ham.

 Appreciate the info, thanks!!


                                 Tom  W6TOM

The NCL-2000 has a set of swamping resistors underneath. You can tap it per the manual for low or high drive power. The grids are driven without tuned circuits so the resistor bank is the load. I use mine in the position where a 100W PEP transmitter is appropriate. The other arrangement will make it work with lower powered transmitters.

I can't say about the drive, never measured it since it is adequate, more than adequate to overdrive the amp, I just look at the amp's output and once it is tuned I adjust drive and audio gain..

Any time you learn to tune around would be a good time. Im on 160 thru 2M AM and I dont make schedules since it interferes with more important things.


I wouldnt try 200W drive into a NCL-2000 on any mode, the NCX-5 at 120W was often a bit much and in the 80's I had to keep the T4-XC's backed down. In days of old I used a HT-37 and then the 100V and they were just the right power plus both could easily be set for 20W on AM.

You'll find Carl on CW on 160 and 80 meters. He doesn't run AM.

No, he really does, or has, or did. He called me once on 80m to say hello when I was still up north. Think it was 2007, maybe 2008. 

Still waiting for my QSL, H-I. ;D

I'd just like to be able to hear your station so I can get a few ideas for improving mine Carl.  :P :P :P :P :P :P :P :P :P :P :P ;D

I'll start looking in the V/Uhf weak signal areas tomorrow.

I just love this secret squirrel stuff.

Good luck in the contest.

Wise ass ;D Ive worked several forum members.

I dont particularly care for 75 AM or SSB so thats one of the last places I'll be found but chasing DX on 80, 160 and 6M is the #1 priority and thats mostly CW.

After that for AM its probably 6, 10, 20, 15, 40, 17, 12, 160 and 75 in that order when propagation cooperates.

LOL. Let's see, you've talked to me, JJ, Todd, JN, and maybe some others at Nearfest. I guess that counts. On air contacts - zero. I still say you don't run AM. You're just clowning all of us or you just want to hang out with the cool guys.  ;D

I've run the NCL-2000 for a few years on AM mostly and its been fine.   I can easily get 300 Watts of carrier on AM using about 7 Watts of drive from my ole Gonset GSB-100.   With the exception of operator error resulting in a fried 8122, its been faultless.  

I found a group of 8122's, for not much money, that resulted in a few "good" tubes, but no matched pairs.   I added a second bias circuit to the amp, and biased the individual tubes to the quiescent current suggested in the manual.   The amp has been happily humming along now for a few months with no sign of bad behavior.  

I have a second amp I'm in the process of converting to 4-400's.   Its a fill in project so its not progressing to quickly.  

As Carl mentioned keep the knob in the GRID position, because that's where the action is.

I trust you mean 4CX400A/GS-36B?

Thats a good swap and a much more rugged tube.