Kevin, think about detuning your 160m transmitting antenna when receiving, this is the first step. Then, if the problem is still clearance, you can try with a simple loop antenna in the following way
By the way, depending the diameter of the coil, line lenght, and coil position, I'm afraid those 6 turns are not enough to have a good choke on 20m. Expecially in cases where a choke is not on a curr
Like this "sounds" much better. A reasonable number of turns for the band in use and a larger diameter winding. Note that each time the number of turns is doubled, the reactance is multiplied by a ra
Unless a small reduction of RF energy fixed the problem, for example lowering the voltage just under a semiconductor threshold, hardly those 6 turns works like an effective choke at 7 Mhz. Only chanc
Nobody told that beyond the resonance the choke impedance goes further increasing, of course it doesn't because of inductor self capacitance. Disregarding self capacitance, which is a parasitic effec
A plate choke must ?resonate? well above the operating frequency when installed and connected to the amplifier circuits. Choke anomalies of such kind are easily visibile tracking for PI return loss,
Hi Tom, the procedure of parking choke resonances out of bands can't be used in a 2-30 MHz continuous coverage unit, and I don't like to have chokes like that in my own amplifiers. When plate choke w
Inverted L does not necessarily need a cap (a reactance) to work and to be properly matched. It may be matched with a capacitor with when its feed-point is looking reactive (inductively), as well as
That antenna is basically an upside down GP with two radials, and it works fine if the radials are quite high above the ground, and if the vertical section is ¼ WL. Opposite to an inverted L t
Sinisa, also I don?t like L unsymmetry, but what do you mean for an inverted T? Upper of the loading horizontal wires, the horizontal section of the inverted T, currents are low and radiated energy i
Beeing Bills? antenna shortened, resonances will not appear on odd harmonics, neither on even ones. With linear elements (not shortened) resonances actually occur also on even harmonics. There, anywa
It?s a good advice if RF transformers for this application are wound as multifilar windings, interleaving wires, each winding covering all the available core space, side to side with the others. If f
The Col-atch-co antenna is 42' tall. On 80m it's purely a capacitively top loaded vertical with a wire hat. Efficiency will be the highest possible for that height, and, of course, function of the us
10 pieces in parallel, each one 3.3ft long, will better approximate a capacitor than a 33ft long single run of coaxial cable, at least at 2Mhz. All shields togheter, one side, all inners togheter the
If the hat has the purpose of substantially loading a short element in the most efficient possible way, then it has to be at the top of the element. If the hat has instead the purpose of loading an e
Assuming the ammeter is based on a thermocouple, your measurement has sense, even if the impedance is other than 50 Ohms and reactive. The same doesn'apply to bird wattmeter, which doesn't measure p
Just as I told and You confirmed, the real power is not directly measured by a bird wattmeter when load isn't 50 Ohms. The real power (when a reflected power is existing) is only obtainable by subtr
Bird 43 is a useful instrument, and I agree with your points about directional coupler meters advantages. Sensors, diodes or thermocouples (bolometers) have instead pros and cons. It remains the fact
Yes, it's true. For some years I used a fixed two elements wire yagi @200 ft (almost straight elements), remotely tuning the passive element as a director or a reflector. Some precise open wire trasm