If I'm reading things correctly, that bit of copper seems to be a bit of shielding, for where the helical antenna is too close to the large circular reflector. The width of this shield is .6cm, and in the picture below, you can see the two distances; .3cm and .12 cm, which deteremines the location and how long the shield needs to be. I don't like how the large square mounting board seems to be made out of alluminium or some sort of metal or alloy, which would just be reflecting unwanted frequencies = noise. I'd say plastic or some dried and painted wood would be a much better mount.
Oops, missed the whole thread. I've been soldering since I got out of nappies (not really, but almost ). Let me go back and have a read through the thread and see if I have anything constructive to add
The bit of copper is not shielding, it is a quarter wavelength transformer, you use it for impedance matching. I know what it is, my problem is how can i calculate its properties...
You haven't missed much. I'm insane, MV use abrasives to clean his tips, and DRX is making antennas. (My specialty as school was radio technology. Oh, how I DO NOT miss that part! (Although making helix antennas, and radio beacons was pretty fun.))
I don't think you can dxr.. let me get my friend on this thread.. he's a electrical engineer I wanted to measure the impedance on my pigtails too.. what you need is to buy the right kind of cable to match impedance.. in my case 50 ohms forget that helical stuff for wifi.. if you want the longest distance- you make a biquad and stick it on a dish, both sides my friend worked on this project for a guy out in the country.. after we sighted in the dishes (over a mile away).. we had a full link at 80mw of power.. 18.5mb/sec transfers and not a waver thing is it is very directional.. you have to point them right at each other and if it rains, there could be issues (the beam is bent down).. this is why you see 2 dishes on phone radio towers- one right under another.. if the weather gets bad, the dish underneath will catch the signal.. then they used to have another set of dishes at a different altitude if those failed.. if all of them failed the switchers would route around the tower I was skeptical too on the dish being any better than the yagi.. but for distance it's unbeatable..
Thank you for the information, it gave me a very good idea. I was looking for information for a university project for a Radiation and Propagation course, I have already sent the report. In the meantime I can say that the quarter wave transformer on the link makes wonders for the antenna, I have something like 3GHz of under SWR=2 bandwidth. An interesting thing I found is that if the helical antenna has a dielectric core with a high relative permittivity you can make it smaller and more directive and at the same time increase the gain. I made my antenna with the dimensions for 2.42GHz and gives me a gain of about 8dBi with 39 coils... kind of low, then I made a frequency study and found that it was getting something like 13dBi at 1.6GHz, the bloody PVC pipe shifted the frequency response.
This,anything abrasive should be kept away from your iron in the same way you would keep it away from your tackle...
hrmm... Mr specialty, can you tell us what is going on with this quarter wavelength transformer, that looks like just a bit of shielding to me Girls like it when boys use abrasives on their tackle, such as a shaving blade to remove all of the hair, and then give them a good rub with something abrasive to ex-foliate! In the op the tips are damaged/worn out, which is why cleaning them with a sponge won't do it anymore. If you don't have spare top on you, it's much quicker to restore the tip to a usable condition, with some abrasive and re-tining, than it is to buy another one. It's just like worn out/weathered paint on a car. Washing and waxing won't be enough anymore, it's time for a cut-n-polish, or sand it back and re-paint.
No. For two reasons: 1: We didn't learn much stuff at that level. I'm not talking engineering here. I went to school to be able to repair, nor build. 2: It's been almost 7 years since I learned about this stuff. I haven't used any of it since, so most of it is forgotten. I just remember that circuits in high frequency radio systems are pretty complex. Not only do the components them selves have a function, but the physical position of the components will greatly affect their performance. (To this day I remember the frustration of reading schematics for a unit, looking for a capacitor that simply wasn't there. (classic example of a capacitor built on the PCB by having two copper tracks running parallel to each other.) As a last resort, then I agree, of course. But most tips can be salvaged with some flux, tin and a wet sponge. It just takes some patience.
