开云体育

Photo of what I had to do to fix the coil wiring [image1.jpeg]

OK....very preliminary results. The effect of putting the relays on the BOTTOM included reversing the POLARITY of the coil wiring......oops!!? I knew that, but was hoping the relays were not polarity

Rod, Your spice model is seriously wrong.? Reason common emitter amplifier gain is a function AC beta and the short form definition of that is FT/F where FT is the device FT (300mhz for 2n3904) and F

Subject says it. rOn

I am software and not good with hardware. So with the FCC reg's issue I have decided to sell my uBITX boards. I have a version 1 and a version 3 boards. I am asking $70 each. This does not include

Doesn't look like meeting before the BARC meeting will work out! Frank (WQ1O) has suggested he reserve the Red Cross room for a meeting. We could set up a "local" digipeater and do some testing. Also

Relay control wiring Brown wire picks off ground. (which is done several other places also) Brown-white picks off TX +12 V First white wire pics off KT one control signal Red wire pics off KT2 control

all those values Chris is quoting for the IN 4148 are completely at variance with data sheet values. https://www.vishay.com/docs/81857/1n4148.pdf? which is good for 100mA forward? and 100V PRV. NB

... and for long unwanted sections, heat and lift one end and rip off the rest.

OK, here are photos of the completed RF wiring. Remember, this is intentionally done in the most simplistic manner possible. Short, but unshielded wires. The red wire, the input to the whole filtering

Dremel? Butchery! Scalpel / craft knife (even box-cutter!) can do a neater safer job. Slice across both ends of the gap you want to create, use your soldering iron/station to overheat the section of

While it sounds like the diodes are lower voltages, should this protect the relays from a near by xmitter?? This is the mod thats mentioned to protect Q13, wondering if the diodes I have will be good

The NTE109 is a Germanium diode, equivalent to a 1N270. It turns on at a lower voltage, about .3V, than a 1N4148 Silicon diode, which turns on at about .6V. David N1HAC

I am going through my stash of diodes and found I had a couple of NTE 109 diodes..? The diode is 60 mA Continuous Average Forward Current, 100V Peak Reverse Voltage.. The 1n4148 is 10ma 20v reverse;

Hope you find it. Better the one that is gone, than if one in the two filters for lower bands was lost. Tom, wb6b

Well, here is the photo of my attempt at cutting traces with a Dremel 200 tool and a tiny little bit that looks like an end mill !! I learned the hard way that you have to hold this thing with two

Investigating transmit gain in UBITX V3 using LTSPICE, Aug 28, 2018 Caveats: all modeling done at 13.8vdc For simplification: q90 collector circuit modeled as parallel feed with 400 ohm load q911-q912

Yes, but we know this is not perfect.? Wrong word should been reasonable.

Yes but you have no idea how many never found it. rOn

Here are photos of the assembled board. I did break down and use shielded microphone cable for the relay control wires. Soldering those SMT inductors was a bit of a thrill with a Walmart soldering