VE7XEN's electronics blog

Antennas Ordered & Future Projects

Shortly after getting my ham license I started fooling around with antennas. Built myself a very shoddy 2m ground plane 1/4 wave just to get an antenna outside for use with my HT, as the whips can't get anywhere from inside. Then I decided to upgrade to a proper antenna - a coaxial dipole design by W6NBC published in the July 2009 QST. This worked fantastically well for a couple of months, then a solder joint broke between the antenna connector and the radiator element. I've repaired it, waterproofed it better and it just doesn't work anymore - I'm scared to transmit into it as the receive signal is so bad. I've taken it apart several times and reflowed the problematic solder joint to no avail - it seems something inside the lamp-tube coax has gone wrong. Given how much grief this design has given me I decided to just pay for a commercial design that will work properly. I considered building myself one of the popular copper pipe J-poles, but without equipment to properly tune it, and with the price of copper it's as expensive as buying one and not nearly as foolproof. I want something a little more substantial than the ladder-line J-pole design.

After a look around at some of the inexpensive designs, I thought I'd stick with the J-pole design and go for an Arrow OSJ 146/440 dual-band J-pole. Based on the reviews this seems to be a well-built, well-performing antenna that should be small enough not to be obtrusive. The only other serious options at a similar price were poorly-constructed ground planes. Anything else decent was about double the price. So I'll give a try, it was only $40 after all. I just have to remember to take care to waterproof the coax connection...

Since I was making an order with a fairly substantial shipping cost, I figured I'd also pick up something else that I want for an upcoming project - a cheap, small, easy to hide VHF antenna that doesn't need great performance. I'm working on a from-scratch APRS tracker design (and making good progress!), and would like my own install to be somewhat 'stealth'. I've selected a small through-the-glass design by Workman, the WEP2000. This antenna probably sucks, but with the 25W radio I plan to use, and just for APRS tracking, it should do the job and fit the criteria of being simple to install and hide-able enough to be less-than-obvious. Perhaps I will swap it for a simple HT antenna used internally to the car later, and use this one for a real radio. We'll see how it performs... it can't be worse than the HT+whip I'm current using while mobile! This little guy was only $25, including a whack of coax pre-attached.

I've also begun construction on the UHFSDR by WB6DHW, which is a 1.75MHz - 700MHz RX/TX SDR based around the Si570. I'll need to add some filtering and a poweramp for serious use, but it should be fun to play with even on its own. Stay tuned for more on that project, as well as my APRS tracker once I get far enough to begin real testing on that.


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