Hello Bill, I think someone is doing some dreaming! That is like putting a large heat sink on the edge of your car radiator and expecting that to keep it cool. Unless they are blowing air thru the tu
When IM products are generated they are equally generated on both sides of the carrier frequency. as Joe says, just flip over to the opposite side band and you can immediately see what the level of t
Why would you want to build a push pull amplifier? Single ended is much simpler. 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting.com http://lists.conte
Push pull doesn't really buy you anything other than reduced 2nd harmonics, which isn't a problem as the tank circuit will take care of that for ham purposes. It is sometimes used on higher frequenci
Class B is More linear than what? You really don't want to run a pair of 4CX1500 in class B at RF. Less 2nd harmonic content at the output with push pull but not less IM products. 73 Gary K4FMX _____
Push pull and class B operation are two different things. You can not run a lower idle current just because the tubes are in push pull. You will get the same distortion products as if they were opera
An autotransformer is in fact a transformer. It works just like a transformer with two windings (primary and secondary). The difference is the autotransformer shares the same winding for both primary
Hi Roger, First, is the circuit push pull/parallel or are all tubes in parallel? If they are push pull you will need two neutralizing capacitors (cross neutralization) If all are in parallel the lead
Roger, if you have a Pi tuned input it is not easy to neutralize. Your feed back (from the neutralization capacitor) needs to be out of phase with the grid. You could connect it to the input side of
To look at the modulated signal you need to do is place the scope probe tip near the antenna coax and it will usually pick up enough signal. If not attach a few inches of wire to the probe tip. Your
Hi Manfred, I suspect that the mixing is happening in your spectrum analyzer mixer setup or even getting in after that mixer. Maybe even into the DDS generator. The strong signal from your transmitte
The amp is only going to be 60% efficient at 1500 watts. At 375 watts carrier only, it will be around 30% efficient. 73 Gary K4FMX _______________________________________________ Amps mailing list Am
Here are some interesting numbers for a typical linear amplifier. At 1500 watts output with a single carrier at 60% efficiency the input power will be 2500 watts. That leaves 1000 watts of plate diss
He is talking about one capacitor for each "leg" of the bridge not a capacitor across each diode. However you do not need any capacitors across anything when using a full wave bridge or voltage doubl
Google "bird slug calibration" and you will find more than you want to know. 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contestin
Paul, With negative screen current the current thru the zener will DECREASE. You need to have enough current in the zener string at zero screen current so it will always be greater than the maximum n
I screwed that one up. I was thinking about a series regulator rather than the shunt zeners. Disregard. 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting
Hi Manfred, Inter modulation is just what the term implies. Two or more signals modulate each other in the signal path. For this to happen there needs to be a non linear device in the path to cause m
Hi Jim, My understanding is that the cathode needs a low impedance to ground in order for the high frequency plate current harmonics to develop properly. 73 Gary K4FMX _______________________________