RCI-2950DX transistors or mosfets?

[dc2rf]

I have a RCI-2950DX with transistor driver and finals (2SC1969's). I also have 3 mosfet IRF520's on hand that I could swap in place of the transistors.

Besides the "negative" of the labor involved in the swapout, is there anything to be gained by the swap? Will the 'fets give more watts out? Would the radio be prone to a greater level of harmonic output?

I'd like to hear the pros and cons from members who have made the swapout.

I know that there is more than just the devices to the swapout... resistors, caps, etc.

I don't mind doing the work if I know there will be a measurable improvement in performance.

Thanks.

 

[GnG8d]

Leave it alone in my opinion.

 

[dc2rf]

359,

Believe me, I hear ya, and understand where you're coming from.

If it ain't broke, don't fix it, as they say.

But I also hope to hear from others who have done the swap, then make a final decision.

Thanks for the advice.

 

[GnG8d]

What are you trying to accomplish?

 

[dc2rf]

Perhaps more power output.

 

[GnG8d]

Then my opinion stands, sorry no help.

 

[dave457]

More power? Get an amp

Sent from my SGH-T599N using Tapatalk

 

[sonoma]

the mosfet if you get them working right will not give you enough of a difference in output to do it. the only person that will know you are putting out more will be you. for an improvement on the receiving radio wouild have to be 100 watt increase. for more and better increase you need an amp.

 

[KD2GOE]

More power? Get an amp

Sent from my SGH-T599N using Tapatalk

X2

 

[dc2rf]

Dave and Sonoma,

I just like to have my equipment doing the best it can do within reason.

Just for the sake of argument, let's say that the radio increased from 25w p.e.p to 35 p.e.p. just from a simple swap of devices. That's something I would do. I already have the mosfets, so the expense is nil. I realize that the change may not be perceptible, but that power increase would be enough for me to justify the small amount of time for the swap.

If nothing else, I'd be making up for some loss in the feedline to the antenna.

 

[dave457]

Why do you want to squeeze every last watt out of your radio?
Should always leave alittle head room, ten watt incress aint worth the time,
but hell.... what do I know

 

[222DBFL]

You will not make up any difference in loss from a 10 watt increase sorry, leave the radio the way it is and get an amp. If you are doing it just to have something to do, then that's up to you, but I will bet that a properly tuned radio will get you more compliments than the 10 watts you are after. JMO, but send the radio to a good tech and have a good alignment and tune done and find yourself a biased a/b amp and you can pretty much talk all around the world when conditions permit. God bless and good luck with whatever you decide

 

[dc2rf]

222DBFL and others,

I'm in a temporary situation at this time. I'm in the process of selling my home. That means that I have a minimal antenna system (a vertical coaxial dipole hung in a tree) and don't wish to put up aluminum that I'll only have to take down later (and also won't look good while trying to sell the house). I don't wish to buy an amp for operation at this QTH at this time. With a relatively low antenna system, I'd only be "blasting" the neighbors electronics with the higher power levels.

I'm not trying to "work the world" at this time. I just enjoy making what I already have work the best it can. I've recently made my own power mike with a homebrew speech compressor circuit built into a cheap stock Cobra mic. It works well and made a real difference with my radio. I've already aligned and tuned up the radio myself.

The reason I'm considering the mosfets is that the later model 2950Dx's have them instead of transistors. Now, this may be simply because the transistors have become obsolete, and that there is no other advantage to them... I don't know.

This is why I'm asking others that may have done the swapout if they have seen a power increase. It would be great if a tech that does this for a living would see the post and respond. I like working on the radios myself and just need a little info from someone who has done this before.

Thanks for your advice anyway!

 

[GnG8d]

The reason I'm considering the mosfets is that the later model 2950Dx's have them instead of transistors. Now, this may be simply because the transistors have become obsolete, and that there is no other advantage to them... I don't know.

That is the only reason. The bipolar junction transistor (bjt) is being replaced with the field effect transistor (fet).

 

[GnG8d]

Just for the sake of argument, let's say that the radio increased from 25w p.e.p to 35 p.e.p. just from a simple swap of devices.

That radio should already do 35-40w pep shouldn't it?