Hi Jim, I see you remembered this! I learned of the tuned choke input idea from the 1964 Collins Radio SSB book by Pappenfus, and also looking at the Henry circuit, a 1950s edition of Terman Radio En
a quantum improvement from years gone by. Per the various tech notes from hammond, sprague, CDE, united chemi-con, etc, the consensus is the CCS DC load current should be no more than the... CCS rip
Keep in mind that the 1.8 kW rating of the new LDMOS 65V parts is not where you would run them for amateur service with reasonable linearity. At least 2 or more devices are run, reduced to the power
I have done it with these methods: One is to find or build an operating impedance bridge. A Delta Electronics OIB2 is the module that was made for HF range up to 1 kW. It will read inline impedance u
Actually it was RCA who made the pink ceramic insulators. It was Frenchtown ceramic, and the material came from mines in NJ. A trace of chromium gave it the good characteristics over plain alumina ce
Polyfet has a 2014 technical bulletin on their website, TB239. It uses their LY942 LDMOS transistor to make a flat 2-30 MHz 400 watt linear amplifier with 20 dB gain, using 50 volt parts. Its a compa
The procedure that David Craig, N3DB, is the extreme but probably best way. For 85 lbs, a plywood box with framing, or even strapping onto a pallet and shipping motor freight are reasonable ways. I h
I looked at my Titan II, and thats an interesting bandswitch (IMHO). Did RF/HV cause failure or just mechanical fell apart? One view of the switch can be seen at: http://hamradiomarket.com/articles/T
Steve, You have 3600 VDC and want to keep the leakage current small, in the uA, no mA. So if that is, say 100 uA, then R=3600/100e-6, or 36 Megohms. RCA recommended never lower than 10 Megohm path re
I concur with Roger, and have always been taught to avoid using Brass fittings in a high resistivity pure water system for amplifiers. Zinc leaches out, but then again, I don't have systems with rout
In the early 1980s while I worked for Broadcast Electronics in Quincy, I ran a series of tests using a 4CX3500A, which is a shortened version of 4CX5000A (lower inductance connections and higher uppe
This is a test. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
What sort of current can your hi potter provide in an arc? Depending on the energy it dumps, you might be careful when raising voltage above the ratings of parts. I would not risk running capacitors
There is a Broadcast Electronics FM10B transmitter available whole or for parts, in Santa Fe. Vintage 1986 or so. The plate power supply is 6600 volts @ 2 Amps, and I am not sure if this one is singl
I didn't know W2ZN was SK. I wonder what became of his Power Pebble rig? I have a Continental 314R1 Power Pebble that is still on 1290 KHz, hasn't converted up to HF. It took a bit of restoration to
Sam I can send you email with schematic of my SB220 that I did a lot of mods and work to around 1994. I still have it but it doesn't get lit up these days. The 10 meter input L was 4 turns on the for
I learned about 8877/3CX1500A7 manufacturing woes from a friend who worked for Eimac back then. This is a summary of what I learned: In 1968 Bill Sain of Eimac-San Carlos developed test models of zer
The LM748 is very obsolete. LM301AN is a similar decompensated old op amp that should substitute. Both have about the same open loop gain curve and the 301 has a flatter phase vs freq plot. It is not
In the commercial RF amplifiers that I have designed, put into production or installed and operated, filament voltage is measured all the time. For pentodes, tetrodes or triodes with common cathode a
Steve's approach is an acceptable method to read the filament on a common grid HF amplifier. The 10 K resistors would optimally be carbon film or comp and not wirewound, so that they are non inductiv