ORIGINAL MESSAGE: REPLY: Sweep the choke across the planned operating frequencies and watch for any drop or rise in impedance at particular frequencies. As a general rule the impedance of the choke s
I have never seen such high impedances at amplifier chokes. Most of the chokes in ham radio amps are not even twice the plate load. The famous Rfparts 225µH transmitting choke is just 2,5k ohms on 16
The RF Parts choke is purchased from Ameritron. The 10X rule goes back to the 30's when everything was series fed plug in coils with link coupling. When shunt feed started gaining popularity in the 4
Hi Carl, Yes, in the late 50s I still used large choke inductances like 2.5mH to feed the parallel resonance output circuit of my 40/80 transmitters and amplifiers. There at the cold end any choke re
ORIGINAL MESSAGE: REPLY: You are right, I mis-spoke. I should have said ten times the reactance of the plate tune cap, not times the plate load impedance. Sorry. Need more coffee. :-) 73, Bill W6WRT
At 2500 ohms reactance of your rfc, the TUNE capacitor probably won't have the range because the rfc is now part of the matching network. And you will go what is wrong with this picture. I have been
ORIGINAL MESSAGE: REPLY: Watch for parallel resonances too. Either one will smoke the choke if they are in or near a ham band. 73, Bill W6WRT _______________________________________________ Amps mail
Gents: About this RF choke resonance thng . . . Isn't there some rule about the choke being open-circuited (no connections to it) and/or shorted (piece of wire across it) when you check for resonance
Using a GDO, you SHORT the choke to check for SERIES resonances. I don't see how a parallel resonance would hurt, since it would create a very high impedance, which is desirable. -- 73, Vic, K2VCO Fr
Vic has it right. Short the choke and use a grid dip meter to find series resonance. For best results the choke should be mounted in place and connected to the tubes and tank. I have checked with a g
ORIGINAL MESSAGE: REPLY: The parallel resonance is accompanied by very high circulating current in the choke. If you think about it, your pi-network is also a parallel resonant circuit with high circ
No load, no current, except for DC Carl KM1H _______________________________________________ _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contest
The parallel resonant circuit will look like a very large resistor to the RF voltage. Circulating current is AC current times Q, but there is none or very little AC current. 73 Peter The parallel res
Hi Bill, I am a bit confused on this. It's been a while - but I was thinking that I read one time on RM's site about creating an intentional parallel resonance on the filament choke. That's a differe
Yep, the principle works from power supplies, audio and RF. I believe Bill is the one confused. Carl KM1H _______________________________________________ Amps mailing list Amps@contesting.com http://
Let me add a little insight here. I believe everyone agrees that a series resonance would be disastrous for a plate choke. However for a parallel resonance there are 2 distinct cases. Case #1: Just b
ORIGINAL MESSAGE: REPLY: Parallel resonance is not a problem if the components can handle it. In the filament (input) circuit, the power is much less and the choke wires are much larger (typ 12-14 ga
ORIGINAL MESSAGE: REPLY: Not so. At the exact frequency of resonance, the circulating current reaches its peak. One example of this is the working of a grid dip meter. At resonance, the circuit under