As a small point, I would have to disagree with the "deepest null" statements. Given a perfect termination (with both resistive and reactive components) the null depth can be made infinite, assuming
The good Doctor Beverage addressed this issue. To see what he thought, take a look at "The Classic Beverage Antenna Revisited" in the Jan. 82 QST. In a nutshell, he recommends heights no greater than
My answer for 160 is to build a special little box that has as many turns of RG-174 or RG-189 as possible on the biggest ferrite toroid I can find, usually using J material as broadcast stations are
Herb: The poor performance over salt water is no surprise. The pattern of an antenna over salt water isn't even recognizable as a Beverage to me. Assuming 5 and 80 for conductivity and dielectric con
Chris: Slowing the signal on the wire is indeed helpful in that the antenna then appears electrically longer and that reduces the beamwidth. That is independent of thetermination issues you mentioned
I - and a lot of DX'ers who specialize in international MW DX - would disagree with this. There are many examples of incredible antipodal receptions, with recent examples being the 300 kw 1557 Taiwan
Of course there is no contribution from the daylight side - that goes without saying. However, I would say 100% of topbanders would call their other-side-of-the-world receptions "antipodal" and 100%
Tom: A season long study of direction finding on Boston reception of MW stations from Europe, Asia and Africa was once done by an ex-MIT'er using 4' air core loops. The results of those hundreds and
Hi Tom: One study never proves anything, in particular when there is extrapolation (MW > 160 m) involved. We certainly agree there. Now we have to agree on what is "accurate enough". The military wou
I don't think the DSL is likely to cause interference. The common implementation (OFDM) and the less common implementation (CAP) both occupy spectrum up to just above 1.1 MHz. As for "notches", only
My experience is the opposite! I had 2 phased arrays of Beverages up for 15 years, one antenna being 1900' and the other 2300' and were used mostly for DX on the MW broadcast band. Separation between
The 71.5 dB is actually S/N, not dynamic range. The Spurious Free Dynamic Range (SFDR) is listed in the spec sheet as 90 dB which is respectable if not top of the line. Chuck From: "Richard (Rick) Ka
I'm not sure I agree with this. The contributors to close spaced dynamic range are the inherent dynamic range of the system and selectivity that will discriminate against interference. DSP filtering
Right you are - neither the A/D's S/N nor the SFDR will tell you the actual dynamic range. The real number is - as you say - limited to 6 dB per bit given no other factors such as gain control in fro
Ford: I'm not sure I understand your test setup - did you have the push-pull and single ended transformers in place while you did the measurements? If so, the "termination resistor" you added is a sp
Ford: I stuck some comments inline. Chuck Hutton Let me respond to these and pose another query. I was under the impression that the termination transformers were to match the characteristic impedanc
This is often not true, but depends on the particular cases. Any tilting of the wavefront induces voltage in a Beverage, regardless of whether the tilt is caused by the incoming wavefront being recei
A few replies are inline. Chuck CH: Then why do all the measured plots from the massive Litva and Rook 1976 report and all the Rome AFB data from the 70's all show patterns that match what I said? Do
I have a different picture of penetration versus soil types. The usual method for specifying RF peentration is to calculate the value where the field has declined to 1/e where e is the base for natur
We'd have to define "doesn't work well". The pattern will be basically the same, but the signal level will be down a bit due to the higher conductivity under the antenna. My favorite Beverage antenna