Hi Stefan and all, I am looking very forward to your test results of your Mini-Dipole + fiber optics. FYI, Last year, I made a Mini-Dipole with an instrumentation amplifier AD8429 set at Av=10 (+20dB
Hello Roelof, Stefan, all, Thank you for your comments. connected to a clean RF earth chokes will probably help. the bottom of the mast This is what I thought, and I made a pi shape filter : Gnd - CM
Hello Stefan, The first earth-point is the tower base. It's a concrete base, abut 1m square, about 2m deep, at about the bottom of the hole, 10 rods (0.9m long) are driven rather radially, before the
Hello all, Now i'm testing the fiber optic vertical short active dipole the first time during the night. A single decode of PA3ABK was possible so far. It would be nice to receive a few more stations
Hello all, I'm continuing my monolog about my fiber optic tests :-) Thanks to the active stations on MF this night. I got a useful set of data to compare the isolated active dipole to my grounded "us
Hello Jan, The tuning of the whip was done in my office by using a noise generator and a spectrum scope. The noise was injected by another small short dipole. After adjusting to the peak i reduced th
Hello Hideho, Stefan, An other way to look at local noise received on the probe is that local noise is traveling over the shield of the coax to the antenna and is picked up by it. When you ground the
Hello Hideho, Am 14.07.2013 15:44, schrieb Hideho YAMAMURA: This is what I thought, and I made a pi shape filter : Gnd - CMC - Gnd. Pse see attached. That looks nice. Thanks for the images. What is t
MF!!! Am 13.07.2013 14:56, schrieb pa3abk: [...] Do you see a difference in signal when you ground your TX antenna versus fully tuned on MF? In other words does the TX antenna has any coupling to the
Thanks Stefan, very interesting please keep up you monologue as and when you have info, I would like to try a fibre connected set up some time, you are well aware of the dirty RF ground at this QTH a
Hello Stefan, Before using an optical link with an active antenna, I have been testing it with a spectrum analyzer. A FSH756V was used as optical transmitter and a FSH350V as optical receiver. Instea
On 13-7-2013 14:28, Stefan Schäfer wrote: .... Due to the lower signal levels of the short active dipole i now resonated the antenna to 630m, where i plan to do my tests. This prevents IM and causes
Hello Edgar, I don't know how linear these devices are, but that will show up in actual use. The SFH756V and SFH350V are housed in a moulded plastic casing with a cable clamp: http://www.avagotech.co
Hi Roelof, Is the signal transfer in the fibre optic transmitter, receiver and cable linear? Also would it reduce the losses if led transmitter and receiving photo transistor were mounted at each end
Hello Roelof, Thanks for your tests. Yes, i agree, these optical components are not the best coice for HF applications. I even didn't expect much from them on 475 kHz but here they still seem to work
Hello Hideho, Thank you. I hope to continue tomorrow or so. I have prepared a list of experiments that i want to do :-) Am 13.07.2013 20:18, schrieb Hideho YAMAMURA: [...] Last year, I made a Mini-Di
