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AM Carrier Level on Kenwood TS-2000

Aug 16th 2015, 12:52

W2NJU

Joined: Nov 18th 2004, 14:12
Total Topics: 0
Total Posts: 0
I noticed what I think is a dangerous quirk in the TS-2000 for guys that operate AM. In the default setting, the carrier level is set at "50." This is way too high, from what I know. If you go to the carrier setting (FUNC/CAR) you'll see the shaded area is way too deep at "50." According to the manual, Kenwood says to adjust carrier level until the pip in the ALC area just starts to show. Does this make sense and can someone explain carrier level? I don't recall seeing it in the exam pool and manual is extremely vaugue. Yet setting this too high, I'm told, will cook your finals. On my rig the correct setting appears to be about "25." HALF the default setting.
Aug 18th 2015, 15:52

WB1GCM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I assume "50" means 50 Watts. If that is the case, 50 Watts is too high. One would need a transmitter capable of 200 Watts PEP for proper modulation. PEP power is four times the carrier power, so a carrier setting of "25" would be the proper level for AM operation.

Bob Allison
WB1GCM
ARRL Laboratory
Aug 19th 2015, 10:39

W2NJU

Joined: Nov 18th 2004, 14:12
Total Topics: 0
Total Posts: 0
Hi Bob. Kenwood does not specify what "50" or any value selected for carrier level is. For all I know, it may be an arbitrary number .Disturbing that a potentially damaging value is resident as their default setting. Many operators would not notice this, unless they were specifically looking for it.
Sep 5th 2015, 00:27

KM3F

Joined: Mar 6th 2008, 13:50
Total Topics: 0
Total Posts: 0
I work AM with this unit so here is my setting and why.
The CXR setting for SSB is 27.
On AM I run a CXR setting of 17. The power control is left at 25.
It does indeed have an effect on power output.
There is nothing in the user manual about the use of the CXR.
More important is the effect on dynamic power control.
This means if you were to run SSB setting for AM and look at an averaging power meter you will see the power go backwards on long peaks.
This is what I call the system 'attacking' the peaks and knocking down the average on short time intervals.
If you run the CXR setting down, it stops the ALC from attacking so aggressively.
The use of a Peak reading power meter can now see the modulation peaks without average reductions.
To go on, I use the CXR setting to set AM drive level to my amplifier.
Usually set for about 85 to 90 watts carrier.
At this level, 4 x the carrier gives you peak power to set the amplifier up to plus a little head room.
Setting the amplifier up this way and making sure you do not drive past ensures no flat topping should occur and working the amplifer over it's most linear part of the transfer curve..
With the TS 2000 set to 3k bandwidth and flat internal EQ, using outboard EQ and wide response mike make very fine clean audio within that range.
The 2000 brick walls at 3100 stock with no mods and will pass audio well below 100 hertz but I don't push the low end.
With this setup I run a $20 R.S. mike and no one can tell the difference between it and a $200 mike.
At an 80 watt carrier times 4 = 320 watts peak time about .9 for the modulation % limit set in the 2000 = about 288 watts AM +/-.
A nice increase over 90 watts peak from just the radio.
There is a lot to it if you look at all the parts and understand the associations.
Good luck..

Sep 11th 2015, 19:50

KM3F

Joined: Mar 6th 2008, 13:50
Total Topics: 0
Total Posts: 0
Correction.
Radio only has 25 watts carrier, not 90 watts.
The drive required to get 90 watts amplifier carrier is less than 25 watts.
Feb 24th 2016, 03:03

W2NJU

Joined: Nov 18th 2004, 14:12
Total Topics: 0
Total Posts: 0
In the carrier set mode turning the carrier level all the way down takes the unmodulated xmtr output to 0 watts. Raising the level to about "16" will get the unmodulated carrier to 25 watts. Increasing to a setting on "25" will activate the first pip on the ALC meter and continude cranking of the knob will yield no further increase in power. The take away seem to be basically: Key AM Transmitter, no audio, raise carrier level till you see 25 watts output. Stop. You're done.

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