* It is possible to attach the RF OUT coax directly to the antenna connector. G) The incoming receive signal is sampled from C14 and connected to the receive strip of the transceiver through the RFX75’s coaxial cable marked RX OUT. This is sent to the S-meter detection circuit in the transceiver through the yellow wire.į) The final RF output signal of the RFX75 is sent back to the radio through the RF OUT coaxial cable where it is connected with the transceiver’s antenna connector *.
#Rfx 75 amp driver
The RFX75 mounts to the back of most transceivers with little or no modification to the transceiver’s chassis.ī) Once installed, the transmitted RF signal from the output of the transceiver’s driver stage (or pre-driver stage) is sent to the RFX75 via the coaxial cable marked RF IN.Ĭ) The driver signal is then amplified through the RFX75‘s ERF2030 (FET1) and then again through the ERF7530 (FET2).ĭ) The amplified signal from the ERF7530 passes through the RFX75’s efficient low pass filter.Į) A small portion of the signal is sampled through C19 and rectified through D3 and D4. THEORY OF OPERATION OF POWERBAND TYPES, DESCRIPTION OF RFX75:Ī) The RFX75 replaces the transceiver’s final amplifier stage and low pass filter section. Most installations will see 75 – 100 watts PEP output power. The output power of the RFX75 varies depending on the transceiver that it is installed on. The RFX75 features the latest Power MOSFET technology and a built in S-meter detection circuit.
#Rfx 75 amp upgrade
The RFX75 is a RF final output stage and low pass filter designed as a replacement and/or upgrade for most 10-meter amateur transceivers. RFX75 is an Amplifier, 75 – 100 Watt PEP Output Power, RF Final Output Stage and Low Pass Filter, Designed as a replacement and/or upgrade for most 10 meter amateur transceivers. 2-I like the tinkering aspect of making this one better.Under the name POWERBAND, the company PALOMAR in USA sells a line ofĤ types of high power replacement final amplifier sections with high performance low pass filter for 10 meter amateur transceivers.Īfter RFX75 and RFX150 they now introduce the RFX85 and RFX85HD. For a couple reasons, this is the right route for me. However, please don't tell me to go get a better radio that doesn't require mods. I'm sure there will be lots of good knowledge to share. Also, I do have an o'scope, freq counter, external power supply, and soldering iron, but NO watt meter or RF or AF signal generator. Will I be okay with a Radio Shack SWR/Power meter for these mods? Please realize I'm not opening up a shop here, just my own single radio. I will be adding simple variable talkback (50-150 resistor) What else component setup would be a good filter? considering direct power from battery (or relay switched by ignition, but from battery) to clean it up some. Where would his help/hurt?Īdditionally, this is in an '80 Jeep with very noisy power when the fan/wipers/heater blower is on. I see a lot of disagreement about clipping limiting diode D-11. What about the RX boost of PLL (switched, with variable resistance of 100K-500K between pin PLL P14 and R11?) is this worth it, or would I be as good with simply the normal cap/resistor? For variable, what should be the max/min levels? Can this cause problems after a final amp mod? What should I avoid?
#Rfx 75 amp mods
Is a RFX 75 really as good as advertised, or are the other Mosfet mods going to be plenty for the price? Is the 520 or the 2030 going to do better? Or should I stick with the 1969, even? Is the 2sc2312 same/better?ĭoes the 2SC2999 RX upgrade (less noise?) work on a 29? Is it worth the time/trouble?Īlso, for the modulation mod, I saw mention of one with a NTE331 or similar with variable pot, diodes, etc. If there was a more local shop I'd go to him for the parts and advice and do it myself with his suggestions, but where I live is a ways away (Norfolk, VA), so I find myself here on the web.īasically, Id like the input and advice as to what are the most effective mods for the time/money?
so want to dive into this radio myself instead of taking it somewhere.
I'm the kind of guy who can't leave anything alone. not including things like echo and roger beep, etc. Digging through here and other sites I've seen plenty or mods for modulation, final amp, RX pre-amp, etc. I'm relatively new to CBs and though I know electronics from years as an avionics tech in the Navy, I don't know jack about this circuit and am not trying to reinvent what's already been done.
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