Sounds like something wrong with the cathode circuit. Suggest the following tests. Inspect the path from cathode to ground, including the cutoff bias resistor, key relay, and bias circuit. Maybe the
This is a symptom of light loading. You don't say about the value of the load capacitor. If it sits at minimum C, then I'd suggest looking for a parallel load C that gets switched out on the high ban
I use Lance (RFDude) Lascari's program under Windows and gsmc-1.1 under Linux Suggestions - Use the same keystrokes as one of those two programs - Show Q circles and estimate network Q on the display
Patrick... A few comments - You need a connection from the 10/25W safety resistor to chassis ground. - I like to put the HV sense on the PA rather than in the Power supply and feed a sample of the HV
I think the pulse operation applies to the 60:1 VSWR specification. Effectively, that gives a specification on how fast the control circuit need to operate. jeff, wa1hco _____________________________
The transistor has two specifications for 1250W output, one for pulse where it handles up to 65:1 VSWR and one for CW...which doesn't have a specified VSWR. I interpret that to mean, if the VSWR clim
Here's more about IMD than you may want to know... I used to work with very low IMD amplifiers for the cellular industry and spent a lot of time studying IMD sources and means of control. I learned t
Here's more about IMD than you may want to know... I used to work with very low IMD amplifiers for the cellular industry and spent a lot oftime studying IMD sources and means of control. I learned th
Executivei Summary: Poor IMD makes for a wider signal at the receiver. For crowed band conditions, receiver IMD is _not_ the issue. All types of amplfiers, so both receiver and transmitter amplifiers
Thanks, Gary... I'm trying to be helpful. On the subject of harmonics vs 2xF1. When I mentioned harmonics before, it wasn't as clear as could be. I'm not referring to harmonics at the amplifier outpu
No I haven't seen anything from the Amps reflector...it seems to operate in bursts. When I was talking about 2xF1 +/- F1, I'm assuming that the signal at F1 is modulated and has some bandwidth. A CW
The CW keying waveform at the transceiver has a controlled rise and fall time to limit key clicks. A linear amplifier will track the rise and fall time cleanly and the level of key clicks will remain
Interesting... I looked up Aryton-Perry winding as a result. The Wikipedia entry pointed out ... "One disadvantage is that because the two lengths of resistive wire are connected in parallel, four ti
I'm so confused. Pin diodes are used to switch RF _power_ and have breakdown voltages in the Hundreds of volts. That is not similar to your mention 10-15 K Volts and a vacuum relay. Also the G41 has
Used one for years for our VHF Contest group and rebuilt it several times. C5 is a flat copper plate about 10 cm wide and 5 tall. It has flexible brass sheet on each end that wraps back to ground to
K9EA sent me a private message about this. I failed to notice something very obvious. C5 spring and the shaft tube should be sandwiched with the chassis between them. Jeff, please let me know how did
Carl KM1H Using a power factor correction cap works when the load is a bunch of inductive motors. But it won't really work for the pulse type load from a capacitor input filter. Power meters measure
Hi Paul.. Check out US Patent 4588958 by Allen Katz K2UYH. It's a common way to linearize solid state PAs for the cellular market back in the day. The basic idea is to emulate the compression curve o
Hi Nuno... See Below This will be my first big project like this, I'm in the beginning of start my first project with an amplifier, and have some questions. I'll start from the Anode tank first then
Here's my take on the tube... The -1000V rating is an absolute max...not part of the RF performance. Looking at the grid voltage vs plate voltage at 4 kV on the anode and RF swing down to 1 kV... * B