Saturday, November 3, 2012

Ham Radio: A 2m Base Station Set Up

I posted some general information about my most recent work to get an amateur radio station up and running yesterday. Now I'll go into some specific detail on my 2m set up, which is up and running in a good enough state to get me through winter (I think.)

Interleaved Effort
The work I describe here happened in parallel with work on my HF station work. While I was up on the roof running antenna cables, I was running both sets of cables. While I was clearing shelf space for placing rigs and power supplies, I was clearing room for both. Fortunately it's worked out, even if it meant being a little less focused at times than I would have liked.

Building a Solid Station
Since I live in a gulch, with 100+ foot tall trees all around, getting a VHF signal from my house to anywhere is a challenge. While I managed to check into a net with a handie-talkie and a ground plane on a broomstick, this is not a plan for routine operation. I managed to check into a couple of nets with this configuration, but the signal reports were less than sterling, I had to chase around with the broomstick to try to find the best places for contact, which changed each time I tried. And having to go out into weather wasn't an appealing prospect.

To get a signal out of here, it was obvious I needed a few things. Like a rig with more power, a proper antenna, and, of course, a good low-loss feedline to tie them together. In other words, everything.

The Antenna
My initial thoughts were to mount the home-made ground plane on something better than a broomstick. But then further help came from a visit to the home of Bill, W6WEM, to have a look at his ground loop antenna (which I still hope to reproduce on my property, though it may wait till next spring.)

He had an unused pair of J-Pole antennas, one for 2m and the other for 440MHz. I don't have a rig for 440 yet, so it's laid aside (my daughter Amaryllis may have plans for it, we'll see.) But the 2m J-Pole I had immediate use for.

I scared up an extensible fiberglass pole that's about 10 feet long, and managed to attach it to a high eave on my garage good enough to stay through good weather. First, I connected to the J-Pole with an RG-58AU stub and an adaptor to go between the PL-259 on the antenna and the BNC on the cable. That went to a BNC to SMC adapter on my Handie-Talkie. I stood on the roof, with the HT just a little too high up to be comfortable, and managed to get into one of the two nearby repeaters I'd hit before with the broomstick groundplane.

With a new feedline, I would be able to raise the antenna higher, and who knows, maybe even talk from inside the house!

The Feedline
The 40m dipole I'd put up before hadn't gotten me any contacts yet. And it had my best piece of feedline for VHF, about 60 feet of RG-8 cable. I also had about 75 feet of some double-shielded 50 ohm cable, some Belden CATV cable on a par with the best RG-58. I could use the Belden cable on the 2m antenna, but its losses at 147MHz would be a lot higher than the RG-8. And the losses of the Belden would be not much more than the RG-8 at the lower frequencies that the 40m dipole would be used at.

So I decided to put the Belden cable on the 40m dipole, take off the RG-8 and put it on the 2m J-Pole.

I then used a collection of adaptors to get from the RG-8 to my HT without breaking the antenna connector (hopefully, though it may of weakened it, as it now needs repair, but I blame it getting caught under the car seat for the likely cause of the actual break.)

The Rig
Next was getting more watts. I bought a new rig, a Yaesu FT-2900R on sale at Ham Radio Outlet. It goes up to 75 watts. Almost certainly overkill, but then it would also have some value if I hooked up a beam and tried to get some DX over FM. Too bad it's not all mode. But that can happen later. Maybe I can even get somewhere with my old Kenwood TS-700A someday, with the other modes.

But for now, I decided to get the FT-2900R. I could have added PL to the old Kenwood and had 20W out, but it's receiver isn't very sensitive. By the time I've added PL and added hardware to compensate for the Kenwood's receiver, I'm within kissing range of the price of a new rig that just does the job for FM. So I went with the new rig. A new all-mode rig would have been nice, but wasn't available at the price of FM-only.

And the Rest
I managed to make out like a bandit at the SFARC annual white elephant sale (as well as getting some bucks into the club treasuring for the pleasure.) I got an MFJ-941C antenna tuner, a couple of nice power supplies (one still in the box), and some other fun bits.

Right now my HF rig and the FT-2900R are sharing a single power supply. The new one in the box is going to become my 2m rig's dedicated power supply.

I also have a place I've made in my in-home office, near my computers, that I've set the rig. I went up on the roof and moved the antenna cable to the other side of the house to meet up with the rig. I used the same feedthrough I made for the living room window in my office to bring it in, though the long-term plan is to bring it in through the crawlspace of the house.

All Together Now
Last week I went up on the roof and did something about the wobbly mount I had the J-Pole on. I put a proper antenna bracket pair on the house, and set the fiberglass pole, at full extension, into it. It's good for winter. The other setup lasted through a couple of windstorms, but frankly, I was surprised it did.

Last Thursday I got all the bits put together and checked out. I managed to check in that night to a regular 2m net for SFARC. Woohoo!

Everything is in a state that it can stay that way all winter, if need be. I'm planning some more minor changes to make things nicer, but it's all usable as is. Nothing is balanced precariously, or too fussy. I'm cleaning out a corner of the room to make space for a dedicated table for amateur radio now, and planning to reroute the antenna cable and put in a disconnect switch for lightning safety (I manually disconnect it when it's not in use, now.)

So I can say that for the first time I've got a real station set up. It's taken almost a year since I got my license to do so. But it's done.

No comments:

Post a Comment