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#1
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![]() "Owen Duffy" wrote in message ... "Sal" wrote in : ... Say, after following the link, above, I just took a look at that AIM4170 web site and it looks like it's more trouble to get it up and running than most things. A lot of the steps are left to the imagination ... or they assume a whole lot about what potential buyers already know. Sal, I bought an AimUHF, and it worked fine out of the box. I suspect that the problem that most hams encounter with analysers and VNAs is that the knowledge of basic complex numbers, AC circuit theory, transmission lines, and antenna systems does not 'come in the box'. If acquiring such a thing is the stimulus for expanding knowledge on those topics using the box as a learning aid, that is great. But to many, they are safer to just treat it as a VSWR measuring device. I am staggered by the popular advice offered to newbies who ask 'why is my VSWR high' on eHam and QRZ to borrow an analyser. The advice appears to offered mainly by people who don't understand the instruments, and possibly have never used them effectively. A classic example is the advice to connect the instrument at the shack end and tune for resonance, for as everyone knows, "an antenna just ain't gonna work any good unless it is resonate (sic)". The getting of knowledge just isn't a priority in a world of instant gratification. Owen Thanks, Owen, I understand the world of complex numbers and vector impedance well enough. My concern is whether I can make the thing work with what appeared to me to be a dearth of hookup instructions. How did you know what cable(s) to order? Are you operating with a software COM port or do/does your computer(s) come with a hardware COM port? Anecdote: Right after Field Day, for which I am the club Chairman, I followed a fellow club member's suggestion to try to get a network logging program running in preparation for next year. No dice. Hours wasted. I followed many conflicting or wrong instructions; the best I managed was to get the two computers to each acknowledge the existence of the other -- but no more. No sharing of information and darn little help from the maker of the software, who assumes we are are all networking engineers. Moral: So, with the bitter taste of failure still fresh, I'm not really ashamed to act shy around this next (possible) installation. As I told Ian, I'll try the software and see if it radiates warmth. It needn't be hot ... just not ice cold. :-| "Sal" |
#2
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"Sal" wrote in :
.... Thanks, Owen, I understand the world of complex numbers and vector impedance well enough. My concern is whether I can make the thing work with what appeared to me to be a dearth of hookup instructions. How did you know what cable(s) to order? Are you operating with a software COM port or do/does your computer(s) come with a hardware COM port? The AIMuhf connects to the computer by USB, just a mini USB IIRC, and I think they supplied a cable. .... As I told Ian, I'll try the software and see if it radiates warmth. It needn't be hot ... just not ice cold. :-| The software is a very important element. In my experience, the software with these kinds of things is amateurish... but usable. I also have a TecTec VNA, but I avoid using it if I have something else that will do the job, and the AIMuhf is usually better if a one port VNA is up to the task. You will see plots from both of those in the article http://www.vk1od.net/antenna/7MDipole/7MDipole02.htm . There are other ham grade VNAs, I haven't researched them deeply, some may be kits or homebrew that leave you challenged to find some of the parts. Owen |
#3
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![]() "Owen Duffy" wrote in message ... "Sal" wrote in : ... Thanks, Owen, I understand the world of complex numbers and vector impedance well enough. My concern is whether I can make the thing work with what appeared to me to be a dearth of hookup instructions. How did you know what cable(s) to order? Are you operating with a software COM port or do/does your computer(s) come with a hardware COM port? The AIMuhf connects to the computer by USB, just a mini USB IIRC, and I think they supplied a cable. ... As I told Ian, I'll try the software and see if it radiates warmth. It needn't be hot ... just not ice cold. :-| The software is a very important element. In my experience, the software with these kinds of things is amateurish... but usable. I also have a TecTec VNA, but I avoid using it if I have something else that will do the job, and the AIMuhf is usually better if a one port VNA is up to the task. You will see plots from both of those in the article http://www.vk1od.net/antenna/7MDipole/7MDipole02.htm . There are other ham grade VNAs, I haven't researched them deeply, some may be kits or homebrew that leave you challenged to find some of the parts. Owen Thank you, Owen. That web page was all very instructive. "Sal" |
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