The resistive bride to detect the vswr is what i am making. ( I made it but there was not enough power to drive it from my transmitter 27jan2015)
Then may be LC tuner will be used. Lets see.... tried this but did not work for me.
Meanwhile during LL qso, VU2KD suggested just put a two diodes and one vu-meter and tune the antenna for max deflections. Actually this shows the antenna voltage. May be know something is going into the air.
|simple tuning help.|
I was little sad, as i did not have swr meter and i brewed this much and tx not putting up on air. Earlier did not feel need for it ! wow. Searched the net I will sure to tune-up and be on air with this qrp rig, but anyway this is process of re-inventing the wheel , it will help lots other hams also. Theoretical knowledge is one thing and actually putting togather is a different thing. Ya, and this is the step towards it.......
then comes the experimental fsm.
when my dsb tx did not work, even the first birdge ckt did not work it was time to retrospect. PA is drawing up the current , dummy load is heating up, receiver is crying loud but does the antenna radiating fully ! FSM is a tool to see the answer in full scale or as bright light.
c1-10pf, c2-33pf, r1-10k preset,r2- 2k2, r3-470k,r4-10 ohm for overall current limiting. d1-d2 are 1n4148 diodes.
Then cw tx was connected to antenna. I placed this ckt near dipole, LED was full bright. But with one or two feet apart it went dark. There was not much RF radiating from the antenna. There was not enough umphhh......
Now, i understood why people did not hear me on 14316kc dsb rig.
The antenna fine tuning / matching and one RF Power Amplifier is needed.
( around Jan2015 made succesffully the single ended RF linearing using the IRF510/IRF840)
(Still ATU has been not made, so this is pending work, may be later on................)