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Have you hit the wall looking for 2879's? Here is a possible replacement
- Thread starter Tallman
- Start date
If you want something closer to 2879 flange type, look at sd2933 or sd2943. But those are 50v VDMos type devices.
Good info. I have always done it on paper or figured out rough idea in my head. It's gotten me by so far. But I bookmarked that site for future experimentation.
So while we are on this subject. Let me ask, what would you gents recommend amp wise for a galaxy 95T2? It's a 150w plus radio. I was thinking 8-12 transistor amp with old toshiba 2879's. Am I close or way off??? Just curious. Thx for any and all replies. I am pretty sure I know the answer, just want to hear it from some experienced amp techs. Again, thx for all replies!! Have a good one.
The 95T has two Toshiba 2sc2290s in it. The factory only rates the radio at 50 watts AM max. Same as the similar older RCI 2990/2995DX base stations (same PA boards) I run those lower than that on AM, but have had no problems thus far pushing a High Drive, Heavy Duty, Toshiba based straight (4) x 2sc2879 comp box. A 100 amp DC supply is required for that set up.
Just got an FT- 950 in to convert the AM low level IF modulation, to modulate a higher level RF stage. I figured I'd post a pic of its RD100HHF1 1.8 to 54 MHz. PA stage. Looks like the output transformer is four turns of coax on the secondary. The front side has been cut so the braids are connected back to the brass primary and the center conductors were just soldered back together. The input transformer is interesting. Primary is one turn of brass tubing and the secondary is two turns feeding the gates. Keep in mind the driver output is from a balanced push pull stage...
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If anyone was curious, 10 hours later and $600 has achieved high quality RF modulation out of the FT-950. Gone is the crappy AM audio produced by the low-level IF modulator. All other modes retain their stock operation and the modification can be switched out of line to revert back to the low-level IF modulator for comparison. This rig has now joined many others from the TS-940S, to the FT-1000D as those with working, high quality AM modulators that I have custom designed.
Shockwave any idea what the difference is between the RD100HHF1 & RD100HHF1C? The C is $45 vs $65 at Rfparts. That Mod you did sound really good but not cheap..my anytone's have better modulation in AM mode then My FT-950.
Shadetree Mechanic
Delaware Base Station 808
The "C" version is RoHS compliant. When you have a choice, you want to avoid compliance here since it eliminates the Beo ceramic which has better thermal conductance.
The 950 is more difficult to mod than other HF rigs because just about every part of the audio circuitry, gets replaced with a custom modulator PC board.