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20 is hopping this a.m. QDX just worked NZ2X on 14074.8 KHz? ( +/- a Hz or two ) -- 72, Bill, N4QA

Yes, non-standard band combos will take trial and error methods. It is not inconceivable that a particular band combo will have a similar problem to that in the QMX; that is some odd notch will give

For me, the difficulty is in modeling distributed C and resulting L at a high RF frequency, especially in high-Z circuits.? Spice modeling is fine provided those nuanced values are correct and are

Hi, staying on the Topic, A) I always check the layout of an HF, VHF or UHF LPF or BPF before making them. Using Elsie. B) Using things like LTSpice is very useful however it is a game of balancing

Jon, There have been discussions and simulations of these BPFs. Many previous posts in the archive. It is made difficult because there are stray capacitances and, in one case (in the very similar

Also new but I've been going through much the same sort of thinking. I think the reason that the theoretical BPF frequencies are too high is because there is parasitic capacitance in the circuit as

Hi Randy, all A topic which comes up often. Our nearest FedEx depot is 250km away in the city of Izmir. It's not like in US where you have a FedEx office in every town. So to get to FedEx they have

Glenn, being OT here already, I just add that for that reason I added a 6 dB pi attenuator at the 10 W linear PA input. Thus still having 20 dB gain and better than 12 dB RL. 73 Bojan S53DZ > >

Good Morning, I'm a newbie to this forum, I'm no EE and less than a year as a Ham. In that context I will ask this question... I'm interested in building a QDX but feel that a 40/20/10 version of

GM Randy, In my case the Tracking lagged arrival by about 3 days and quickly got caught up at delivery. It seems that “shipped” means a label was created, after that I think that they loose it,

Hans: Have you shipped our order, yet? HIF

Would like to know where this goes as well. So far, I can envision multiple signals and the like, bit such things have always fascinated me. HIF

My QMX kit was marked "shipped" on July 14 and at the same time FedEx emailed me a tracking number. Checking the tracking status showed that FedEx was awaiting the package. This status has not changed

Going a bit further OT: I wonder what you guys think of the Kostas SV3ORA crystal oscillator circuit http://qrp.gr/multiosc/index.htm which oscillates several crystals at the same time? He took some

Hans, Thanks for that info! I am pretty certain QMX will outperform uSDX by a good bit! You are off an excellent adventure here and we all are eager to see your results! JZ KJ4A

Hi John I agree, and were this not the case, everyone would be using EER for ham radio transceivers. Practically speaking I measured a 37dB control range over the RF amplitude, without magic; and a

Willie, I am still working on this and do not have a finished response for you yet. I have added an "AM modulator" to my basic QDX amplifier simulation. I set the power supply voltage to 6 volts and

I've used SimSmith to model filters and then play with component values to see how changes in value make a change in the plot in order to learn what modifications I need to fix my filters. SimSmith

I believe it is not an OR but an AND situation. There are times when building is a better choice than modeling (though I would challenge that the "model" is in your head and needs to be built to

Chris, LTSpice, like any simulator, depends on a reasonably accurate model if it hopes to represent something near actual behavior of a circuit. This becomes more and more difficult as you go higher