Friday, February 25, 2005
The equipment arrived
I must say I was impressed. The parts I order from http://www.rfshop.com.au arrived last night so I go right into makeing the antenna.
Cutting up the coax was really quite easy. As suggested in the instructions I used a hacksaw and managed to create the 8 segments plus tail in about 45 minutes. The only thing I had to be careful of was I ended up with a slightly different and less lossy coax than the instructions called for and so needed to adjust the dimensions.
The coax I got was the LMR-400. The article warns that each type of coax has a different velocity factor but provides no indication of where to find this information so a quick search on Google found me at http://www.timesmicrowave.com/telecom/pdf/LMRIntl.pdf which tells me that it is 85%. The dimensions in the article are for a cable with a velocity factor of 66% so some dimension adjustments were required.
The hard part proved to be the soldering. I made up the jig the article describes but found that too constraining so I removed one pair of timber blocks. This worked well by giving me an extra set of hands but not constraining how the cable was held. Even so soldering was a nightmare. The solder sticks to the core just fine but it does not stick very well to the braid. Some of the connections I must have soldered 6 times and even now I am not so sure they are ok.
With the soldering complete I attached the N-Type connector with no real dramas (although I did need to thin the core down to solder it to the centre pin. I then tried to insert it in my standard electrical conduit. I am not sure what diameter it is but it is a fraction too small so it will be off to the hardware store tonight to get a slightly bigger diameter piece.
Of course even without the cover I had to test it out. Unfortunately with the stuff available in my house the results were inconclusive. I am hoping to do some more extensive testing over the weekend once I have it properly complete and have access to the WAP.
Cutting up the coax was really quite easy. As suggested in the instructions I used a hacksaw and managed to create the 8 segments plus tail in about 45 minutes. The only thing I had to be careful of was I ended up with a slightly different and less lossy coax than the instructions called for and so needed to adjust the dimensions.
The coax I got was the LMR-400. The article warns that each type of coax has a different velocity factor but provides no indication of where to find this information so a quick search on Google found me at http://www.timesmicrowave.com/telecom/pdf/LMRIntl.pdf which tells me that it is 85%. The dimensions in the article are for a cable with a velocity factor of 66% so some dimension adjustments were required.
The hard part proved to be the soldering. I made up the jig the article describes but found that too constraining so I removed one pair of timber blocks. This worked well by giving me an extra set of hands but not constraining how the cable was held. Even so soldering was a nightmare. The solder sticks to the core just fine but it does not stick very well to the braid. Some of the connections I must have soldered 6 times and even now I am not so sure they are ok.
With the soldering complete I attached the N-Type connector with no real dramas (although I did need to thin the core down to solder it to the centre pin. I then tried to insert it in my standard electrical conduit. I am not sure what diameter it is but it is a fraction too small so it will be off to the hardware store tonight to get a slightly bigger diameter piece.
Of course even without the cover I had to test it out. Unfortunately with the stuff available in my house the results were inconclusive. I am hoping to do some more extensive testing over the weekend once I have it properly complete and have access to the WAP.
