Why is the KL 200 P slightly higher in price than the KL.203 P at Cooper Electronics?

[FlyBoy50]

This subject came out in another thread and I often wondered what makes them different and why do more people buy the 203 P ? Back in the beginning when I went to buy my first amp with my uneducated thinking I chose the 200 P because I thought it must be a little better built to raise the price up. Time to educate my knuckle-head ! LOL Thanks

 

[doffo]

I am taking a wild stab at this... Isnt the 200 P a "pill" transistor vs the 203 P running on 4 MOSFETs? Least thats what it looks by the boards.

 

[9C1Driver]

Yes, the 200P has a single sd1446 final. The 203 has the RM3 mosfets.

 

[19wrc333]

I am taking a wild stab at this... Isnt the 200 P a "pill" transistor vs the 203 P running on 4 MOSFETs? Least thats what it looks by the boards.

Correct.
Any of the RM amps that ends on "03" uses MOSFETs.

 

[Greg T]

I learned something valuable today!

 

[FlyBoy50]

Yes, the 200P has a single sd1446 final. The 203 has the RM3 mosfets.

So which final is considered better the sd1446 or the RM3 mosfet and why? For the sake of learning !

 

[9C1Driver]

The best option would be to have amplifiers built with the older finals because they were actually designed for transmitting. Examples would be the Toshiba 2sc2290 and 2sc2879. I think this also applies to others like the sd1446, mrf454, and mrf455. These have been discontinued now, HG is remaking the 1446 and 2879. These remakes are in the 30-50 dollar range each.

Today ham radio's use mosfet finals also designed and intended for transmitting. I had to have two replaced in a Yaesu FT-991a and they were around 60 bucks each.

Many of the mosfet finals used by say RCI today were/are used as switching transistors in power supplies. They discovered they could make them work as transmitting devices. Since they are like 2 bucks each or less they use them. This is just one of several reason why Ranger makes a crappy product these days.

Mosfets are kinda here to stay so I hope improvements in amplifier design happen. These LDMOS amplifiers look promising. To answer your question there is not a lot of difference between a kl200p or kl203p. The mosfet amps don't like to be overdriven and they don't like higher SWR levels. I would say the 1446 final is more robust then the RM3 and has better audio gain.

 

[AudioShockwav]

So which final is considered better the sd1446 or the RM3 mosfet and why? For the sake of learning !

The 1446 it is a good transistor, it's actually a VHF transistor that works very well at HF frequencies around 28 MHz.
Rated at VHF frequencies for @70 watts it produces about 25% more at 28 MHz.
In the past the MRF 492 I considered to be the top of the transistor pile before the Toshiba 2879 came along, now both of them are gone.
The only transistor that is currently available with more power output at 12 volts is the HG 2879 and to be honest if you have a working amp with 1446's it's fine.

73
Jeff

 

[FlyBoy50]

The best option would be to have amplifiers built with the older finals because they were actually designed for transmitting. Examples would be the Toshiba 2sc2290 and 2sc2879. I think this also applies to others like the sd1446, mrf454, and mrf455. These have been discontinued now, HG is remaking the 1446 and 2879. These remakes are in the 30-50 dollar range each

Thank you, so what I get out of this is my first decision to buy the kl 200P because it was a better build wasn't totally wrong,but I later bought a 2nd amp and it was a KL 203P so I have both and I'll probably will never know the difference because I'm not technical enough ! LOL So let me ask, What does the KL 300P have in it for a final because I have that one also ?

 

[FlyBoy50]

The 1446 it is a good transistor, it's actually a VHF transistor that works very well at HF frequencies around 28 MHz.

And what your saying is the KL 200P might be a little better amp for talking 10 meter radio. I think I heard that somewhere else along the line in my exploration.

 

[AudioShockwav]

Me, I still prefer bipolar transistors but most of them are gone, that's primarily why I have old stuff.
There are guys building with switching mosfets and they seem to have a handle on them, there are now amps using them close to the KW range.
Hg is about the only source for 12 volt stuff and as time goes on I am sure people will optimize the builds with them.
Real RF devices now want 48/50 volts.
I don't know what the current 300 uses, probably Mosfets but I don't know.
RM has the capability to build really nice stuff, they are just not building it at the CB level/price point.

73
Jeff