There is also a possibility that diodes used like this will cause IMD when used near a strong RF Field. I agree with Roelof, don't try to fix a problem that isn't there. I have used the antenna less
Marco ! The 100nF is just to remove DC from the pad (6V).... I wonder if static cracks will induce enough voltage to clamp the diodes but I will find out as Roelof said in his post. Roelof ! It's not
Lightning strikes to ground are, I believe, by far the most damaging type. Many kV / metre, even approaching MV/m can be induced in teh ground. People standing with feet apart in line with the st
Hi Roelof, My antenna was mounted 15' off the ground with a ground wire connected to the coax braid right under the antenna. The lightning was not in my yard so I can only guess within 1 mile of my h
Another approach is to include a small 12V "telephone" type relay at the input to the amplifier, and powered from the same source. The relay would short the input when de-energized. John, W1TAG I'm c
Hello Marco, This question comes up from time to time. I have not had a single report of failure, due to mounting the antenna close to a transmitting antennas. The J310 is quite sturdy. Steve Ratzlaf
No, I don't want to transmit with the miniwhip :-) !!! The question is, how does the miniwhip behave in an electric field of some kV/m, that is, close to the transmitting antenna in 137 or 500 kHz? A
Dear all for input protection I am using one 1N4148 from gate to ground and another one from gate to the positive rail, both diodes in reverse polarity, independantly whether the device is a FET or a
Hello Mike, Thanks for the report of your antenna failing. How far away did the strike hit? And how did you install teh antenna? Maybe we can learn something out this failure. 73, Roelof, pa0rdt
Hello Roelof, If your friend has a problem, I will sent him 10 J310's for free! Please send (at least) 240 J310 :-D Thanks for the answer. Marco IK1HSS thanks as well. 73 - Marco IK1ODO
My MiniWhip got nailed by lightning static within the first year it was up :-( Mike WE0H This question comes up from time to time. I have not had a single report of failure, due to mounting the anten
Hello Marco, It is amazing how eager everybody is to solve a problem that does not exist! The best approach of course is to try it. The cost of a J310 certainly justifies the experiment! 73, Roelof,
Hello Gerhard, the 100n capacitor will do nothing, it is in series with the input pad capacitance (a few pF). The diodes will clamp at 0.6 V, that is too low (every static "crack" will send the diode
Hello Mike, My antenna was mounted 15' off the ground with a ground wire connected to the coax braid right under the antenna. That is interesting. This might imply that the ground at the antenna is a
Hello Marco ! I'm currently also playing around with a MiniWhip and had exactly the same concerns. It's not the original design because the 2N5109 wasn't available and so I used a 2SC24?? (don't reme
