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Driving a 75 ohm coax plus dipole antenna directly from a 50 ohm transmitter should be fine, that is not enough of a mismatch to cause trouble so long as the antenna is cut for the operating

I think what changed was your voltage regulation. These chips can degrade under some conditions, especially the cheap clones. You are getting noise feedback through your power supplies. As for the

what is the remedy if i'm using 75 ohm cable?

Your very correct!! This leds to mixing problems and confusion. Thx for clarification on this topic. Secondly this radio is an awesome learning tool intermixing rf..with high speed stable micro

Use 50 ohm coax and a 1:1 un un balun

Hello dear people, My issue may be stupid one because i'm new to this. A horizontal dipole have the impedance of 72-75 ohms. so the feeder can be of 75 ohm cable. But bitx40's output impedance is 50

Jerry, Well said. The yellow wire is an accident looking for place to happen. it usually hangs out right over the main receiver PCB Thanks for the heads

ok that sounds like a better idea and i can reuse the pin again. I just used a2 since I'm all synced up

Rather than clipping wires at the pushon connectors just use something small to depress the little catch pin on the connector; through the rectangular hole and slide the wire and connector out. The

Good call.. what really puzzles me the most, though, is that until yesterday, I had no tuning clicks and the 7.199 birdie was almost inaudible. Suddenly, both were very noticeable and annoying. I

That sounds like basically what I plan to do once I get the replacement si5351's.

The WireUp instructions at http://www.hfsigs.com/bitx40v3_wireup.html ( http://www.hfsigs.com/bitx40v3_wireup.html ) show the red wire from that same connector to be the VFO from CLK2 of the Si5351

Can someone tell me what the Yellow Wire that is on the 5 pin connector is and how can i address it in my script?

People have reported in the past that a large electrolytic cap across the Raduino 12v can clean up the clicking, which agrees with your finding. ?I'd go with a cap plus resistor as Farhan is using to

I added 1000pf cap and .1uf cap parallel on the 5volt regulator and a 50 ohm resistor in series with the audrino power and I don't have any clicks anymore but still have the birdie but I can deal with

Good & bad news.. After trying a variety of ways to figure out where the tuning noise was originating, I finally tried powering the Raduino board from a separate 12V supply. That totally eliminated

Here is the two hacks discussed in this thread the left is the 100pf across L7, the right is the two 1n4148 diodes placed across K1 pins 12 and 16(gnd)

Lee, yes I agree that wire shielding and arrangement can have a great effect on the tuning clicks. Especially shielding the wires to/from the volume pot have great effect. But not on the 7199 kHz

Someone was asking about the display mounting being too far back/not flush with the display opening. Grind down the standoffs about 1/16 inch and the display will be snug up to the panel. The Tindie

I have rebuilt / changed mounting and wire routing several times seems to have greater effect than anything else. filter, shielding etc like the old days of computers caps everywhere lol. just my