RFX-150; anyone seen this before?

[Shockwave]

I don't dispute the fact they work. I just recognize from a technical standpoint the circuit is lacking to say the least. At 45 watts of drive for 150 watts output it still falls short of adding a single S-Unit or 6 db. The very first solid state RF final stages were producing more gain than this at 150 MHz in the 1970's.

The transistors gain starts falling apart at around 10 MHz. Not at all characteristic of an RF MOSFET but very much characteristic of a power supply switching transistor. RF MOSFETs don't experience a reduction in gain at their upper frequency range unless the part has extremely high gate capacitance and high inductance leads just like the ERF7530.

 

[Lil'Yeshua]

My RM 203 makes a difference in someone hearing me at a distance and that's only 90 ish watts + ERP from my A99/FS99/GPK1 concoction so the rfx150 ought to get me over low signal level skip a whole lot better. Please splain Lucy.


P.S. I get the point on crappy components. The Chinese,gotta love them but shouldn't they take a history lesson from the Japanese?! Not only copy a design but make it better not shoddy with just enough to where you have a good regifting item for Christmas?

 

[AudioShockwav]

I get the point on crappy components.

It is not crappy components, it is devices pressed into service that they were never designed for.
When these first started to hit the cb market, they called them high drive units, that is because you need a lot of drive to produce any reasonable power from them.

Have to love it when builders take a negative thing (poor gain) and turn it into a good thing (being able to drive your high power radio into a amp ) and tell you how good it is......


73
Jeff

 

[Onelasttime]

Originally the RFX150 was called the DX 1o0 I had one back in 1992. I can not recall if it had 1 MRF455 or 2x MRF455 I do know that by the time it was stollen it had 2 mrf 455 transistors mini-pressurized cooling, High gain low noise pre driver and driver and upgraded voltage regulator for the main chassis. Ungraded recieve. I also ran radio shacks top of the line power mic. It did not matter if it was DX or local I was bending needing with a 102 inch SS whip. I was well known in Hinesville Ga. Fred brilliantine was my Technician. I hope he is still alive! Good Man. People always thought I was a base.

As I understand it the circuit has remained mostly intake. If you wanted to retrofit bipolar transistors be it the MRF 455 or a 1446 you could do it.

keep the power turned down and let it swing. If you want to NPC it NPC the bipolar finals not the mosfet finals and all is good!

 

[222DBFL]

For the power gain of 100 watts, from the needed 40 to 50 watts to drive it, totaling 150 watts, it might not be worth it. Like someone posted, it's not even a 6db gain. But it may be enough to get you over the pile I suppose. Granted a well setup antenna system and 50 watts, vs. a well setup antenna at 150 watts is 3 times the power total. So it's close to the 6db point.
Whether they are work well or not I think will be determined by the person installing it. Here is a photo of one. You could sWAP out the transistors couldn't you and replace them with a set of ones that are used in newer HF radios couldn't you?? Or is this not possible?? Just curious. Or would it then not be worth it?
I could see this being a good deal for someone with limited space per say, like a spot to add and external amp. I would go external amp if at all possible, but this unit doesn't appear to be too bad other than the misused transistors. Or am I missing something here? Though most RF MOSFET transistors were AB biased as well, or is that not correct either? I am trying to learn so don't flame me here fellas. Just curious!!
Only time will tell I guess as to whether or not these units actually do perform well and hold up for a while. The RFX85 on the back of the magnum 257HP has way more wiring than this one does. Looks to be a pretty straight forward install. Still need proper equipment to tune them properly. But for $100 what else can you get that will give you 150 watts pep?? Again, I'm just curious about the above posted questions. Any and all replies are appreciated. Good day to all.

 

[Tallman]

But for $100 what else can you get that will give you 150 watts pep?? Again, I'm just curious about the above posted questions. Any and all replies are appreciated. Good day to all.

Those are great for truckers who work for companies that will not allow external amps mounted in their trucks. Also when they don't get a truck that is permanently assigned to them. I like my radios to be all in one. Like this one:
http://www.hyelectronics.com/Ranger-2970-DX-Mobile-Radio/productinfo/RCI-2970+N2/ I think I'll go buy one tomorrow. I like those Ranger 2970's for mobile.

 

[9C1Driver]

Those are great for truckers who work for companies that will not allow external amps mounted in their trucks. Also when they don't get a truck that is permanently assigned to them. I like my radios to be all in one. Like this one:
http://www.hyelectronics.com/Ranger-2970-DX-Mobile-Radio/productinfo/RCI-2970+N2/ I think I'll go buy one tomorrow. I like those Ranger 2970's for mobile.

Just understand that a 2970DX cannot be run off the dash posts of a semi, must go to the battery direct.

 

[Tallman]

Just understand that a 2970DX cannot be run off the dash posts of a semi, must go to the battery direct.

A lot of companies approve of the use radio to avoid traffic. But they do not want trouble with the Federal gov't by allowing flagrant violations that could cause them trouble. Most of them do not realize or have the tech savvy to spot the ham radios which would require modification to operate on cb band. I guess it all depends on the company what they will let you use. I have had a rough day and I'm going 10-7 or QRT.

 

[undertaker]

 

[357]

Looks like it wont work on a Cobra 138xlr....too bad.

 

[Tallman]

Looks like it wont work on a Cobra 138xlr....too bad.

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I think you are giving up too soon.

 

[9C1Driver]

Looks like it wont work on a Cobra 138xlr....too bad.

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The RFX-150 has been out for well over three years, if anyone can install it this guy probably can. Doug at http://customcbradios.com/ he has done things that most shops can't.