Hello, lowfers! I wonder is any methods to estimate theoretically groung loss resistance of transmitting LF antenna (T-antenna with wire conterpoints mainly but others antennas also). I have good exp
Hi, Rik and Group. So far I haven' found any formula for rectangular loops, unfortunately this is the most common shape for big transmitting loops. I have derived the formula for rectangular loop. It
Dear Ric and Group. If you are ready for receiving I would recommend to try to copy DCF39 on 138.830kHz. This commercial station runs about 30kW ERP and is located near Magdeburg (Germany, JO52WG). I
Hello, Ric. L = 0.8*B*(ln(A/d)+6.82) where L = loop inductance in uH, A = loop height in m, B = loop length in m and d = wire diamater in mm At first sight there seems no (practical) limits to the A/
Hi Group. I sould someone to add. only for elevated conterpoise. The formula is: R=(1/(pi*s) * [(1/la)*ln( (H+h)/(2*H) ) + (1/lc)*ln( (H+h)/(2*h) )] where la - antenna length, lc - conterpoise length
Hi Group. Previosly I have sent the formula for estimation of LF antenna ground loss if conterpoise length is equal to antenna length. If conterpoise length is not equal to antenna length situation b
Hi, Group. It seems to me extremely worth then formulas show the conderpoise wich lie on soil surface is the extremely bad case. To reduce losses conterpoise should be elevated or burred to adequate
Hi, Group! I have just derived formula for ground loss when conterpoise is burred. Configuration is the same then conterpoise is elevated. But now h is conterpoise depth. Also wire radius r appears i
Hi John and Group. Putting in the same antenna details as before, the new formula gives 38 ohms, still too low by a factor of over 2, but much better than with the first formula. May be 93 - 38 = 55
Hi John and Group! Hi Sasha, Putting in the same antenna details as before, the new formula gives 38 ohms, still too low by a factor of over 2, but much better than with the first formula. I just com
May be if conterpoise is up from the ground it is posible to decrease ground loss compared to case when conterpoise lie on the ground or is burred. More exectly: "... to increase antenna effectivity
Hi, Group! I have derived more acurate formula for ground loss then previous one. This formula show previous formula is extremely aproximate. Factor of number units was losssed... New formula is deri
Hi, Rik. TNX for the coments. I believe there is a misunderstanding, the antenna wire (Lant) remains long (several 10's meter), only the counterpoison (Lcp) is reduced to 0.2m (small ground rod). Thi
Hi, Rik. too large (eg. salt water) the counterpoise won't be of much use. On the other side even for s = 0 (worst soil you can think of) R won't be endless as the counterpoise will still work. I for
Hi, Rik. I agree about Lcp is really 0. But if I take Lcp = 0.2m (short ground rod only), Lant= 30m , C = 150pF (Xc = 7800 Ohm) and a = 0.01 then R = (Lant/Lcp)*a*Xc = 11700 Ohm. I believe that this
Hi, Rik. I agree about Lcp is really 0. But if I take Lcp = 0.2m (short ground rod only), Lant= 30m , C = 150pF (Xc = 7800 Ohm) and a = 0.01 then R = (Lant/Lcp)*a*Xc = 11700 Ohm. I believe that this
Hi, John Most probably you are considering a flat surface and perhaps an entirely vertical antenna? This may be all well and good for a commercial antenna, but amateur antennas like mine are not on a
Hi, Rik! I believe the limitations of the formula probably are : 1.The ratio Lant/Lcp should not be too big or small. Increasing Lcp far beyond Lant won't be a great help. On the other hand, even wit
Hi, John. Are you sure that you have written the formula correctly? Omega (2 Pi f) appears in "a" in the numerator and in "Xc" in the denominator and therefore cancels out, making the formula frequen
