Jim, You may have seen one of those dual square boom logs where the coax runs into back-end of one of the square tubes and then all the way up the inside where it attaches to the feed point at the fr
The boom acts like a sleeve balun, since the rear area of the log has the lowest voltage. Some Jerold commercial VHF logs were built that way, although they still had some coax common mode currents.
Hi Tom, First of all, I'm very nervous about dipping my toe into the pool where the big boys swim, but here goes. First of all, the MANY that you refer to has now been decremented by 1. Thank you. I'
Enjoy your lunch- this appears to be a good occasion for fruit, as in "Apples and Oranges".He was referring to Gain, while you argued about S/N. There IS a difference. Bill At 01:46 AM 7/30/2004 -070
I would think narrower azimuthal Presuming it does, you are correct. Any additional directivity (not gain) increase in the dorection of signal would result in the same improved S/N when the noise is
What's an FOM? And, for us non-engineers, bottom line, can we still safely say more efficient antennas with more gain are going to tend to be better, in general, than less efficient antennas with les
No... consider the noise as just another signal, so increased gain in a particular direction (of the signal) increases the noise AND the signal by the same amount. SNR stays the same. 1) VHF or highe
might What you describe sounds a lot like a diversity receiving system if you assume two receivers at each end. But one really big caveat is that you must account for the arrival time and polarity di
Another good example is the small receiving loops with a sharp null broadside to the plane of the loop. As far as gain goes, they are pitiful - at least 20 dB below even a mediocre vertical. But ste
I don't think what you are saying is correct, Jim. If the noise is uniformly distributed, increasing antenna directivity will not change the total noise power received. The higher directivity antenna
might What you describe sounds a lot like a diversity receiving system if you assume two receivers at each end. But one really big caveat is that you must account for the arrival time and polarity di
Sorry to have taken so long to respond to this. I'm told, by many people who know a zillion times more about this stuff than I do, that increasing antenna gain doesn't improve received SNR under the
about this stuff received SNR the receiver conducted the That explanation still misses a few things in cases where external noise sets the noise floor (the normal HF case). 1.) If the noise is EVENL
<snip> Directivity vs gain... You can have a directive antenna that doesn't have much gain (i.e. it has loss). A good example would be your first directional antenna, with the same gain, but only 60
Hi Tom and Jim L First of all, thanks very much for your replies. I devised this simple model in the belief that it would reveal to me why a yagi will hear stuff a dipole won't, even though noise lev
R5 vertical will often never bothered show noise from beam. I'm a big fan of diversity receiving systems. I use stereo. I use spatial diversity on 160 and 80 meters because I only have vertically po
Ralph Wallio W0RPK tried this and had some success: http://users.crosspaths.net/~wallio/POLAR.html _______________________________________________ See: http://www.mscomputer.com for "Self Supporting
This is a very popular technique... (it's simple, and makes use of that wonderful signal processor between your ears) The researchers who are studying this (they're in France, I can't recall the nam