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This area is for discussing the KL300P Review.

Author Message   Pcovington Posted on Monday, December 24, 2001 - 3:34 pm:        Hello, I am a little confused about your SWR measurement in your review of the KL300P. Are you referring to the SWR presented by the amplifier to the radio - in another words the SWR looking onto the input of the amplifier? Thanks, Phil   Pcovington Posted on Saturday, December 29, 2001 - 10:35 pm:        What is the purpose of measuring the SWR between the amplifier and antenna? Thanks, Phil   Jyd Posted on Tuesday, January 01, 2002 - 8:16 pm:        to keep your stuff from burning up.   Pcovington Posted on Wednesday, January 02, 2002 - 10:48 am:        >to keep your stuff from burning up. No Really? LOL What I mean is that if the SWR is, say, 1.3:1 with the amplifier off, the SWR will be 1.3:1 with the amplifier on. The SWR meter sees the antenna and feedline not the amplifier if it is placed between the amplifier and antenna. Unless you have something terrible going on with your feedline/antenna you should not see the SWR change with increasing power. If you do it is more likely the inherent measuring error in the SWR meter and nothing to do with the amp. I would think a more meaningful measurement would be the SWR looking into the amplifier with the amplifier off as well as the SWR looking into the amplifier with the amplifier operating at different power levels. This is what I want to know: How does telling us the SWR reading on the output side of the amp tell us anything about the quality of the amplifier? Phil   Marconi Posted on Friday, February 01, 2002 - 4:16 am:        Nice report, How about a report on the KLV base amps? What does the variable knob on these amps do, control the dead key like variable watts on a radio? Are the tubes available, where and how much? Do they have a fan inside and what is the noise level it makes. Marconi   Rosco Posted on Friday, February 01, 2002 - 2:23 pm:        Question about SWR meter : I operate a Galaxy Melaka Base, 2nd in line is a 300/P KL, and then last a Radio Shack Digital SWR/Power meter, hook to my antron 99 Is this the correct hook up profile, SWR on channel 20 is : 1.12, less then 1.1..............Or is the correct hoop up the following way. Galaxy Melaka, Radio Shack SWR/power meter, then 300/p to antron ?? Thank you. Rosco . It seems the SWR/Power Meter the way I have hook up is last, then antenna,. This would allow power out put from linear to be read   Honkytonkman593 Posted on Friday, February 01, 2002 - 7:54 pm:        nope gotta do it radio/linear/swr meter/ antenna one to one is good dont change it!!   Warlock Posted on Saturday, February 02, 2002 - 9:52 am:        Reading swr between radio and amp shows whether or not the input tuning of the amp is matching to the output impedance of the radio. This needs only to be checked once unless you change something. Experimenting with diff. jumper lengths can get this reading to be lower. (No flames on this one) The nice thing about having a swr meter AFTER the amp is to let you know if something goes wrong. Sure, if your swr is 1.5 with amp off, it should be when amp is on....UNLESS... something is off. Antenna, coax, connector, or ground could be or later become faulty, without the meter you won't see it. Seen by swr change or power change.   Rosco Posted on Saturday, February 02, 2002 - 11:52 pm:        Thank you Honkytonkman 593 and Warlock for your imput. I have been a cber' since 1972, my memory is not what it use to be, I always play it safe, and ask for feedback, just to be sure. Thanks to both of you. Rosco 308, Bob , Indiana   Inspector Posted on Saturday, February 16, 2002 - 3:26 am:        I modified my KL300p for Class AB operation, from it's origional class C. I also added a blue LED next to the power LED, to indicate key-up and modulation. It works excellent on SSB driven with my 2950DX, into a SP2000 antenna.   Galileo Posted on Saturday, May 04, 2002 - 7:55 pm:        Inspector, I would like to hear more about this...Can you give some details.....What did this do for you??? Thanks...   Cavatist Posted on Monday, May 06, 2002 - 4:11 pm:        I'd like to know what people think of the KL500 amp? I recently purchased this amp from Copper and I couldn't be happier. I get nothing but rave reviews. By far the best mobile amp i've ever owned.   Magnum410 Posted on Monday, July 29, 2002 - 11:14 pm:        Tech181 In the review of this Amp it says the frequency is 3-21mhz Can I still use this amp on 10-11 meters? (not that I will or have ) The reason that i'm asking is that this is the only amp that I have that drives the SWR through the roof when I key it up. Do I just need to recalibrate the SWR with the amp on? Thanks Magnum410   Phineas Posted on Monday, August 05, 2002 - 10:48 am:        Magnum What you are you may be observing is Standing wave in your harmonic ranges. When you amplify at a given frequency(27mhz) you are also amplifying 54mhz, 108 mhz, etc... Naturally, your antenna circuit is not tuned to these frequencies so your harmonics will show as reflected power. There are things you may be able to do. 1. Adjust your antenna system at high power. This however can be dangerous due to RF burns etc. This is still no guarantee that your match will be 1:1 2. Re-calibrate your SWR meter at the higher power setting. Usually, if the SWR is good at low power, it will be fine at high power also. You may also consider dumping that single needle SWR meter, and getting a meter that measures forward and reflected power at the same time. That way you can better see whats going on with you equipment. Persoally, if I hook an amp in line, and the line matches at low power, I just leave it alone. Why you may ask? Because the Amp has 2 matching circuits in it. One between the radio and the transistors, and one between the transistors and the antenna. Unless the antenna system is very out of tune, everything will look matched down the line anyway. Saying that, if at low power on a given frequency you read a 50 ohm load from your antenna system(1:1 match) your amp will be matched to the same load. Phineas   Magnum410 Posted on Monday, August 05, 2002 - 9:43 pm:        Phineas Thanks for the reply! I'm going to hook it back up and see how it goes. 73s Magnum   Inspector Posted on Sunday, October 06, 2002 - 7:55 am:        I posted this elsewhere so I figured I should put it here also. To bypass the pre-amp in the 300p, clip the center leg (base) of transistor TR3. Add a switch to the cut and it is now selectable (only when power is on). This deactivates the pre-amp relay thus bypassing the preamp circuit. This is also a good temporary fix for a blown TR4 preamp transistor until you can replace it.   Inspector Posted on Sunday, October 06, 2002 - 8:15 am:        To convert to Class AB, isolate the grounded-end of the input transformer (T2 in the schematic, T1 on the circuit board). To do this, I used a Dremel tool and a small grinding bit to cut the ground foil...Use DMM to make sure there is no continuity across the cut. Since there is limmited space, a simple bias circuit needs to be used. For this, I soldered a 100ohm/10w resistor to +Vcc, to the other end of the resistor the anode-end of a large silicon diode..cathode end to ground. At the resistor-anode junction, add an RF choke, the other end of the choke to the isolated tubes of the input transformer. This applies about 1.5Vdc to the basses of the RF transistors keeping them "on"....Class "AB"...ENJOY!   738 Posted on Friday, December 19, 2003 - 6:45 am:        What did you use for the RF choke? Thanks.   Mikefromms Posted on Thursday, January 15, 2004 - 7:54 pm:        What happens if you add additional fuses to the hot and ground leads? Can this hinder the voltage getting to the amp? mikefromms   Mikefromms Posted on Friday, January 16, 2004 - 7:14 am:        Is there such thing as too many fuses? mikefromms   Mikefromms Posted on Friday, January 16, 2004 - 5:29 pm:        Anyone?   Damyankee Posted on Friday, January 16, 2004 - 8:16 pm:        Mike, Actually any time you make a connection there is a potential for loss. A fuse is a connection of sorts. I just use 1 fuse ON EACH LINE. Put these as close as you can to the battery so that they protect both the radio AND the lead (wire) that runs to it. A shorted lead direct from the battery that isn't fused can ruin your day - read "burn up your vehicle and everything inside it" 73's - Ron   Kc0gxz Posted on Saturday, January 17, 2004 - 9:18 pm:        Mikefromms There is absolutely no advantage in having more than one fuse in each positive and negative line. And speaking of that, I always wondered why the CB industry never double fused their power cords. Most of the mobile HF Ham rigs are double fused. Jeff, kc0gxz.   Mikefromms Intermediate Member Username: Mikefromms Post Number: 142 Registered: 6-2003 Posted on Thursday, April 15, 2004 - 1:27 pm:        This 300p really is a good amp. I wish there was a way to turn the preamp down. The db gain in recieve is about 50% too high. mikefromms   Mikefromms Intermediate Member Username: Mikefromms Post Number: 185 Registered: 6-2003 Posted on Wednesday, June 02, 2004 - 10:28 am:        Great 10 meter amp! I'm getting good results with about 1 watt into the high side of the amp. No more lighting up my gages problems nor shutting off my electronic shifter either! I can be heard 25 to 50 miles on this thing in my mobile with locals. It's loud and clean. When motor noise is not an issue, the pre-amp really does it's thing. I've seriously thought about getting one for the home unit. I wouldn't drive it hard, but not sure a 10 amp continuous power supply would even handle it for modulation swings up to 80 or 100 watts. mikefromms