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Thank you all for your kind words and valuable feedback. I will then leave the idle PA current near 500mA per device despite the current drain. I have contemplated adding some series

Well if you look closely there is some reactance at high frequency in the gate circuit to compensate for high capacitance loading at higher frequency. Thats a real tight rope to walk though because

?Didn't realize he has L3 in there. I have the boards and parts somewhere and may eventually get around to building it! This would form a series circuit (to AC ground) with the gate-source

The WA2EBY amp has also been simulated, including notes on what those inductor values are: ? ??/g/BITX20/message/41269 Somehow WA2EBY managed to get good performance without any

Gordeon, please have a lok on the "famous" WA2EBY amp. He is using inductors in series with teh gate-bias resistors. My explanation is that this inductor of unknown value together with the gate-souce

Farhan is actually referring to Mitsubishi transistors. See this message posted earlier today for some information:?/g/BITX20/message/41910 -- Karl Heinz - K5KHK

That 40% drop explains a lot. I would still like to see that confirmed by test. It could also be compensated for on board to keep the drive level flat. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK

If you elect to set a reserve price, be warned that it turns off a lot of potential buyers and therefore will not bid. I usually just set a starting price for about the lowest I would take and let

You have a few options. You can list with a buy it now price that you set, or list it for bids and let the bidders drive the price. You can set a reserve price on the bid that has to be met before

?The old fashioned solution for capacitive loading was simply to put an inductor in parallel tuned to the desired frequency, to cancel it out. In my ancient vacuum tube rigs, they do that in the

I have an unbuilt Bitx40 and many accessories that I no longer have the time to build and am looking for advice about setting a price on EBay.? It is one of the early versions, Serial Number 156,

As reported here:??/g/BITX20/message/40938 an LTSpice model of Q90, Q911,Q912, Q92,Q93,Q96,Q97 shows that with the IRF510 gates clipped free of the circuit, the signal available to

Thanks vk2eka. Very informative study of the rd16hhf1 in a microbitx! 72/73 de Chas ai4ot

https://www.youtube.com/watch?v=sEQNAekjkNk

I believe option #2 will work with 4 powerpoles?as well - at least that's how I used 'em. Cheaper, too. To increase stiffness, you'll have to pin each of the sets together - I use the little black

John, Thanks for this great info! I like your cross legged RDs :-) Raj

Do you have a link to the video? Thanks Marco - KG5PRT

John, thanks for the intensive research on the PA stage. To my experience the RD16HFF1 really need a very high quiescent current of about 500 mA each--- not good for a QRP design. The output

That's exactly what it means. The efficiency is dropping as the frequency is increasing indicating that some of the components in the RF chain are not optimal. Again what is needed here is for

Recently on a youtube video it was suggested that Toshiba output transistors might provided a little more power out for the ubitx. Does someone have the actual part number for the transistors being