开云体育

The builtin FT8 reception works great.? I'm hearing stations from around the world. However, I'm having trouble transmitting.? Software has been updated to the latest available today.? I've entered

The RD16HHF1s are no longer in production. There are some really good parts from Nexperia. They have no easy names like 807 or 6146. They have names like AFT05MP70. Why have short names when you can

We went through that same questioning process. Someone dinged us a few days ago because we're using the IRF510's. Out answer may be different because we are aiming the T41 at experimenters who may

I guess the best way out is to use a robust transistor pair like the RD16HHF1 which can withstand infinite SWR, match the antenna regardless of the impedance at either end with an inline swr meter.

There's an excellent wikipedia article about this transmitter:??https://en.wikipedia.org/wiki/Grimeton_Radio_Station "The Grimeton transmitter is the last surviving example of an Alexanderson

Not sure which statement that would be. I've been making lots of them. A resistive SWR meter assumes that the transmitter wants to see a 50 ohm resistive load, but the transmitter will not necessarily

Yes, the transformer at T8 matches the extremely low impedance coming out of the IRFZ24N's to something near 50 ohms.? There is also a discussion here about an external antenna matcher to match that

My first guess for having different values of SWR reported at different power levels would be that the SWR measurement device cannot accurately measure the two power levels.? This does make sense to

Jerry, A resistive bridge SWR meter should not work if this statement is true. Am I missing something here? 73 Evan AC9TU

Good to hear! If so, then all should ignore my previous post: /g/BITX20/message/94334 Jerry, KE7ER

I would tune up any antenna matching network (if you have one) at low power, that should be close.? Then increase power and tune again. Alternantely, use something like an Antuino or nanoVNA to do

If it works well, it's good. This does not strike me as all that odd. I wouldn't worry unless it somehow caused significant distortion in the transmitted signal. Jerry, KE7ER

There is room for doubt here. An SWR meter assumes the transmitter wants to see a 50 ohm resistive load. A uBitx/sBitx might work a bit better into a load that is somewhat different than assumed.

David, Here is the explanation as I see it. First, the impedance. It is the ratio of voltage to current. Let's skip RF and only consider DC, then we will expand this to DC. Ex 1: Consider a 12 supply

Correct David. How come so many still believe the myth that a bunch of passive elements ( antenna system) actually changes with power level? simple, they have a crappy SWR meter. It either has poor

This is not correct.? The output impedance of the PA does not change the SWR and resistance/reactance of the tuner/antenna combination. What one is really doing is tuning out the reactance of the

Please forgive my ignorance but I've never understood statements like this.? "That is because at lower power, the output impedance of the PA will be different." Since SSB is all about audio (no

If the receiver goes down to 10kHz you can try to catch the sendings from the Grimeton transmitter at 17.2 kHz. https://grimeton.org/en/ ( https://grimeton.org/en/ ) or

Got it "turned ON" just for a moment before heading out to my teacher pre=planning day, today. Used a safe 12V wall -based laptop power supply, will need to replace with connectors for a REAL power

Well that's not good!