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Palomar RFX95HD

My multimeter is at work, so I can't measure anything at the moment. So I tried adjusting it while listening to myself on my Cobra 148 station monitor. The vr1 comes mid point from the factory, adjusting it slowly one way did nothing. So I adjusted it the other way, and the only difference I could tell is with it all the way to the stop. I tried backing off a little, but it wants to be on the stop. But now it sounds great, 25w ssb from the radio gives 100w peak out, which is exactly what I was hoping for. Talked some DX, the heatsink was warm but not hot. I will take some measurements this week before I put it back in the truck.
 
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Well....... I couldn't leave well enough alone.

With the bias up, I was getting a 60w carrier. Ok, so I will just adjust vr14 down to get back to 20w. Then modulated for a few seconds, and then carrier was 30w. Strange. I should have stopped there. Adjust some more, and pop goes the fuse in my distribution. Crap! Pull the fuse from the RFX, radio itself suffered no damage. RFX is apparently toast. Fired up the iron and removed the little beast.

Now to find a new transistor.
 
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Shadetree Mechanic said:
Well....... I couldn't leave well enough alone.

With the bias up, I was getting a 60w carrier. Ok, so I will just adjust vr14 down to get back to 20w. Then modulated for a few seconds, and then carrier was 30w. Strange. I should have stopped there. Adjust some more, and pop goes the fuse in my distribution. Crap! Pull the fuse from the RFX, radio itself suffered no damage. RFX is apparently toast. Fired up the iron and removed the little beast.

Now to find a new transistor.
Click to expand...
Well dad gum dude, you really blew it this time .
Resized_d9a1cb66-f29d-465a-838c-5b6e4aa0134e_191753889925962.gif

I just had to... but on a more serious note, trucks is the only one I could find that had them. I even emailed Eric Lewis and he pointed me to Lesco but they will only sell to a business. I stopped the chase there and that's all I can tell you.
 
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They would need to have at least 2xERF9530 better yet something like a single NXP MRF300. Anything less than that is a waste of time.

A single HG bipolar like a HG2879 or HG2290 etc....
 
If they want it to be monkey simple toss it in a small box like any other amplifier that is not being hooked to the radio and not being wired into the radio! Include some jumpers and some high quality velcro and call it a day!
 
Just the other day going through a box of parts I ran across 12x ERF9030 and 12x ERF2030. I should have 20X Max Mod's some place as well. Bought them when they fist came out and never did anything with them.

I am sure I will find a use for them at some point. Not selling them that is just a hassle to do when that is not what you do. I forgot I even had them.

I remember when they made DX100's in the 1990's and they had a single MRF455 in them maybe a MRF454 I do not recall.

Using a single cheap non-RF mosfet is a total loser design. It lacks power and durability! If this is the best they can do working with China they need to get out of the game! If this your day job you should be able to out perform guys working in their basement that do this for a hobby!

There are many ways to do this! They could basically copy the design of a modern export radio's output section and strap to the back like a Stryker 955 what is that 2x drivign 2x cheap switching fet's?

The real problem as I see it is that given the lack of durability of non-rf fets used to generate rf into questionable matches and the total lack of reliability in supply chain who wants a box that takes a proprietary transistor you know you likely will not be able to source when it fails??? It is not if it will fail only a matter of when will it fail!!!
 
Shadetree Mechanic said:
Just bought some 9530 at trucks. Has anyone successfully installed one of these on a sideband radio? I might be able to put a relay in to only turn up the bias in sideband mode.

truckscbsales.com

Palomar ERF9530 mosfet transistor

Palomar ERF2030+ mosfet transistor
truckscbsales.com truckscbsales.com
Click to expand...
So did you ask Truckscbsales about it? I am guessing you bought everything there? I would have asked them. The worse they could do is look at you point and laugh and then tell you their bench fee. Never know they might have given you some tips or pointers???
 
Onelasttime said:
So did you ask Truckscbsales about it? I am guessing you bought everything there? I would have asked them. The worse they could do is look at you point and laugh and then tell you their bench fee. Never know they might have given you some tips or pointers???
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I will play with it some more when I get it back together. I did not ask Trucks. I am going to set it up with an ammeter this time so I can find the turn on point of the transistor. But it truly did not sound good unless the bias was all the way up. Apparently it can sound good far away while not sounding good on my monitor radio? So maybe it sounds like poo when I DX and nobody will tell me.
 
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Had a few minuets yesterday on the back bench, got it put back together and back on the radio. Bought a bench supply from Amazon, made it real easy to find the turn on point of the transistor by watching the current display. Dialed it in and checked it out, sounds great. I have it set right below the point where it turns on, but I wonder if I should set it a little lower? Is it possible that the bias will be too high when there is a little heat in the transistor?

This is the one I got:

Amazon product ASIN B08DJ1FDXV
 
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Shadetree Mechanic said:
Had a few minuets yesterday on the back bench, got it put back together and back on the radio. Bought a bench supply from Amazon, made it real easy to find the turn on point of the transistor by watching the current display. Dialed it in and checked it out, sounds great. I have it set right below the point where it turns on, but I wonder if I should set it a little lower? Is it possible that the bias will be too high when there is a little heat in the transistor?

This is the one I got:

Amazon product ASIN B08DJ1FDXV
Click to expand...
Please report back on your over the air results, curious to know how it does.
 
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