| Home |
| Search |
| Today's Posts |
|
|
|
#1
|
|||
|
|||
|
Andy there is an old saying " let the buyer beware"
How much did you PAY Reg for using his software and did you get what you PAID for ? Cheers mate Art "Andy Cowley" wrote in message ... Andy Cowley wrote: "Dan Richardson " wrote: On Thu, 15 Jan 2004 13:02:25 GMT, Andy Cowley wrote: You also have modelling programs which don't work. Can you please provide a list of these "non-working" programs? Danny, K6MHE Dear Dan, An addition to my last post about Reg's dipole3.exe:- With these settings l=1, h=6, w=1.5, s=0.2, f=1.8, 'Input resistance' is given as 248.4 ohms. Even if it is assumed that all the antenna current flows to the end of the wire, the wire resistance can't exceed 0.08 ohms, the correct figure being closer to 0.04 ohms, assuming linear current distribution. For a short antenna it is obvious that the radiation resistance must be less than that of a dipole in free space i.e. less than 73 ohms. That leaves a contribution of at least 175 ohms for the ground losses. Increasing height to h=1000 (effectively free space) the ground resistance falls to 136 ohms. There is something very wrong here. Increasing the wire diameter produces big reductions in the 'Input resistance'. I feel that the RF wire resistance/wire losses are being incorrectly calculated. I'm fully prepared to be corrected if I'm wrong about this but Reg has so far failed to give any satisfactory explanation of the results I obtained. If I am wrong, I will, of course , make an unreserved apology to Reg. Perhaps someone with more skill and knowledge than I have can check what I've done? I used EZNEC to simulate an identical aerial and got very different results. vy 73 Andy Cowley, M1EBV |
|
#2
|
|||
|
|||
|
Art Unwin KB9MZ wrote:
Andy there is an old saying " let the buyer beware" How much did you PAY Reg for using his software and did you get what you PAID for ? Cheers mate Art That's exactly why I said 'Let the user beware' and not the buyer. I paid Reg nothing and got something worth less than that. I think a program like dipole3, which Reg proclaims to be accurate and useful, should do what it says on the tin, even if it is free. There is plenty of free software that is reliable and correct. There are plenty of free software authors who are prepared to explain how their stuff works and to correct malfunctions. Reg is not among them. I paid for EZNEC and got very good value for money. The free version of EZNEC is correct and accurate within its stated limits. I'm not complaining that Reg is trying to rip people off, he obviously isn't, just pointing out that not all his stuff does what he claims it does and that users should be aware of that. vy 73 Andy, M1EBV |
| Reply |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| Inverted ground plane antenna: compared with normal GP and low dipole. | Antenna | |||
| Loading Coils in 20th ARRL Antenna Book | Antenna | |||
| Poor quality low + High TV channels? How much dB in Preamp? | Antenna | |||
| Current in antenna loading coils controversy | Antenna | |||
| Current in antenna loading coils controversy - new measurement | Antenna | |||