Is there a chance to read a signal that produces 0 (zero) dB S/N ? What does it happen increasing that signal by 2 dB ? Is it detectable a 2 dB S/N ? Two divided by zero is equal to ? ....sleep well.
OK. Since we are on the way to be correct and precise: 1) A decibel is not logarithm OF ratios of power. 2) A decibel is a decibel, in other words a number, independently if ratio of power, or voltag
I don't know what Steve meant, I know that even a 2L multiband quad is a challenge and final F/B fair when some band is close to each other or harmonically related. Modeling and tests proved to me t
Place a 12m director in front of the 10m driven and see what happens using your modeling software, or roughly check how the 12m director lenght converge to a 10m reflector using the typical formulas.
I like plain and reliable systems, expecially with antennas. If I where to install a single 5 bands antenna covering from 10 to 20 meters, I'd probably go for a log periodic or a trapped yagi. 73, Ma
The double sleeve on 10m is useful to broaden the bandwith that is smaller when using a director. Inherently, the double sleve has neglectable effects on gain and F/B. What helps (a bit) with a dire
May be I'm a bit o_ff t_opic, but rising to the top of a shunt fed element with the fed wire and connecting there we obtain a folded unipole. The ratio between the radiator diameter and the fed wire
Removing the first trap, the 10m one, it's also removed its loading effect and the tubing lenght before of the 15m trap has to be made longer, practically a 1/4WL on 15m. On 20m the loading is origin
I find very efficient and often much cheaper than using ferrite beads a choke made with a proper coaxial line, moreover the coax choke is linear and predictable in behaviour and response. Resonating
Hi Pete, unfortunately the only way to improve a connection is to use a better connector. Bad or oxidized ones shouldn't be used or recycled. I think that Hams have been always too cheap with cables
By far, a few turns of self amalgamating tape over cables and connectors is the best among the simple and effective solutions. A good cable and a connector type that prevents moisture migration is an
The open wire line, expecially with the larger spacings, has the tendency to radiate, mostly in the higher bands but at certain amount also in the lower ones, expecially when the load is not matched.
matter where the fed is, has a maximum current density way off the base. The maximum radials density should be in that area where the current is maximum and not close to the base like with a classic
The higher band in the open sleeve cell is inherently much narrower in bandwidht than a free 1/4 Wl radiator. I'm not sure the open sleeve is a good idea in this case where the bandwith has to be con
The many thousands KVs developed at the edge of a vertical aren't manageable other than with a big glass or porcelain insulator and a knife contactor, just likewise it's used to sectionalize along hi
A classical parallel resonant trap can be made resonant and isolating at a frequency but shows inductive reactance at lower ones. You can isolate the top hat on 40 with a trap, but then you can't use
Proper linear loading has no gaps compared with coils and Q is better controlled. I had very narrow BW with a 2 element yagi on 160m using coils while it was much easier to obtain a pattern with line
This effect is even more evident in verticals, I mean in shunt fed verticals and expecially in those (short) ones loaded with a capacitive hat and using an omega. As well as for the small loops, thi
If my memory doesn't fail, the stacking distance by boomlenght was something grown many years ago in the VHF/UHF to roughly approach a maximal stacking gain with the smallest spacing in case of very
Once I couldn't us an Autek analyzer because it was fooled by the RF field produced by a medium power FM Broadcast transmitter, located several hundred meters away. I have been reported the same by s