ARRL

KM3F

Joined: Thu, Mar 6th 2008, 13:50 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
RF noise cancelling at VHF frequencies. Nov 20th 2012, 03:59 2 2,420 on 20/11/12
SWEEP testing a radio from the Mike jack. Jun 4th 2012, 04:57 3 1,261 on 4/6/12
Power Line Interference. Sep 23rd 2011, 01:07 6 2,395 on 11/5/12

Latest Posts

Topic Author Posted On
Hooking up an Amplifier kb3knx on 15/1/16
First, you don't need the 704 box. The radio will key the amplifier directly with a cable connection.
Second, if your tuner is rated for the radio and is less than 500 watts rating, it won't take the output of the amplifier at it's full rated output.
Place the tuner between the amplifier and antenna.
Adjust in for low SWR, then it's ready for the amplifier power.
Learn how to tune the amplifier quickly on low drive first, then reset at full power. Do not adjust at low drive then run full drive without peak tuning at full power. Also running low power thinking you save the tubes actually make them run harder with more dissipation.
Good luck.
Net Check-in Validity AD6FC on 3/11/15
We have a wide area network that does checkins by referral.
No other local nets do it this way in this area.
All hams are encourages to check in as part of why they have obtained a ticket.
Nets would not function if there were no checkins.
They cannot participate in any activity whether equipment testing, emergency support or any other activity if they are not present on frequency.
Tell them this simple fact..
If they were called into service as hams would they respond.
If they had an answer to a question, would they respond? etc.
You have to get them off the shy post to be of any value to ham radio otherwise all they need is a Scanner or receiver to do what they do..
Bottom line is there is no excuse.
Good luck.
Looking for a local Ham Radio Supplier renegadebaileys on 4/10/15
There is none in Pa for radios.
Supporting equipment and parts, yes.
You have to go the HRO in Delaware for hands on radios.
Good luck.
AM Carrier Level on Kenwood TS-2000 W2NJU on 11/9/15
Correction.
Radio only has 25 watts carrier, not 90 watts.
The drive required to get 90 watts amplifier carrier is less than 25 watts.
AM Carrier Level on Kenwood TS-2000 W2NJU on 5/9/15
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..

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