Posts Tagged ‘Antenna’

A Return Update

5 March 2015

It has been a weird beginning to the year for me.

I fully meant to return to this blog well before now, but somehow writing for my blog just wasn’t a priority. From time to time, I’d think of something to write about, but I just never sat down and actually did so.

From an amateur radio standpoint, I’ve been working to develop something I refer to as The Thumper. It’s based on something I read about in a blog post where the ham described his fondness for CW (Continuous Wave, aka Morse Code) and an on-the-air experience meeting a group of deaf learning ham radio and cw. The original Thumper was mentioned only in passing, and described as “a device that attaches to their forearm and taps them to indicate the Mose Code being received.” I have various issues with LED displays and my current tactile transducer setup leaves much to be desired. For The Thumper, I’d started by utilizing an Arduino driving a RC servo and while that does work to an extent, it has an inherent speed limitation that I don’t like. Almost anything over 10 wpm keeps the servo at the end of travel, making it impossible to detect the characters. I’m now looking at using a vibrator similar to those in cell phones, compliments of a good friend and fellow ham. Although not what I originally envisaged the vibrator does show better promise and a nice theoretical response to faster CW speeds. Coupled with a LED, it may turn out to be the best solution for me to listen to the radio. I know, but the combination might turn out to be better than the parts. Right now, I’ve only got the Arduino driving the vibrator. Still to be done is receiving and converting over-the-air CW signals provided via the audio jack of my radios.

Plans are under way for more Owyhee explorations, and while doing that I fully intend to try HF radio work from way out in the middle of nowhere. I’m building an end-fed, multi-band wire antenna that should be tuned to each band: 10m, 20m, 40m, and 60m. It’s only mobile in that you can easily carry it coiled up in the vehicle, to use it you have to park and deploy it. We’ll see how that works in practice, but I’ve got good expectations. I’ll be focusing, of course, on CW and PSK but when solo. If I have a friend along, I’ll be trying some phone work as well. More than likely, I’ll be band scanning and if I hear anything, I’ll pause on that and see if I can contact the other person.

Photography-wise, I’m currently teaching a beginning photo class, but with a twist. In all my previous classes I noticed that there was never a deaf or hard-of-hearing person attending. This time, I told the community education group that I would teach a beginning class in sign language. When I shared this idea with the few deaf community members I knew, the enthusiasm was outstanding. In the end, due to various reasons, there were only three in my class. We’re having a blast and there would have been at least two more were it not for an age limitation posted on the community education web page. That limitation didn’t apply to my class, but that exemption information was not passed on to the people that wanted to sign up. Word’s starting to get out there about this class, though, and I’ve mentioned I’ll offer it again, the same way. One of the reasons for doing this is that I just felt like turning the tables on the regular offerings…they’re oriented towards hearing people, the deaf have to get an interpreter. This time, though, it’s the hearing that have to get an interpreter if they try to attend.

I have also been investigating the use of the Shutterbug Remote with my Pentax K3 DSLR. Testing with an iOS device showed that the remote works well with the K3, but I’m getting crashes using the Android version of the app on my Samsung Galaxy Note 4. Testing with a Samsung Galaxy S5 shows it works reasonably well with that phone, so now I’m trying to determine whether or not it’s a setting, a FW, or a HW issue with my Note 4. An email to the developers has not provided any response, so I’m very unimpressed with the customer service aspect of their website. Enough that I’m not providing a link to it. It would be really nice to get this remote working with my phone as it’s a great little device which when used as an intervalometer provides better timing control capabilities than the built-in intervalometer mode of the K3. If I can’t get it working, I’ll definitely have to create an Arduino intervalometer or something.

I’ve built a new woodworking bench (above) in my garage along with a DIY woodworking bench vise (below). These will come in handy when I start building the Vardo.

On the Vardo front, I’ve started gathering materials to modify the trailer for the Vardo. It took me a while to figure out the best way to use my flatbed trailer for the Vardo, and still be able to easily use it as a flatbed trailer. One of the things I had to deal with was me being “greedy.” The flatbed trailer is 12’ by 6’ and I had been doing my designing based on that entire area.

Image of a 6 foot by 12 foot utility trailer with one pair of wheels. Sides are an open framework of angled metal. Tail gate is about 4 feet tall when up and contains a metal mesh. Parked next to a blue-green 1992 Chevy Blazer in front of the garage in the driveway.

This is the new utility trailer that will become the base for the Vardo. I’m especially happy to get the all metal bed.

I was going to have a big Vardo that had luxurious room inside. Kind of a contradiction to my original plans for a simple, cozy Vardo, actually. As a result, one of the things I had to figure out a way around was the six tie-downs on the trailer bed near the sides. I finally realized that they provided a perfect way to fastend the Vardo to the trailer, a la pickup campers: straps built onto the framework of the Vardo that connect to the trailer tie-downs via turnbuckles. To do that meant I had to narrow the width of the Vardo box to fit inside the tie-downs enough that I could hook them into place and tighten. It’s only a 6” loss in width, give or take, but it also freed up the solution to another issue: I wanted to put the same kind of mesh that I had on the tailgate along the sides of the trailer. That way, things put in the trailer wouldn’t roll out under the existing side rails. And I could use that now open area to store poles for awnings, and other such gear.

I’ve been doing quite a bit of fishing lately, for rainbow trout. Normally I would catch and release trout, but my wife and I have found that we like the fish. I’ve learned to fillet them so that we don’t really need to worry overmuch about bones while eating. Only about 15 minutes from my house is a great little pond where, so far, I’ve always managed to catch my limit every day. I didn’t use to fish that much, or to enjoy it, but I’m finding I do. I’ll probably go fishing rather regularly while retired, using that to supplement our diet with fresh fish on a regular basis. It’ll be interesting to see how the fishing goes as the weather warms up.

Advertisements

It’s been a while

22 October 2014

It has been quite a while since my last blog post. There’s been a lot going on in my life and at work so that I’ve not felt any desire to write at all. Now that things are starting to settle down and sort out, I think I owe my few readers an update, if only to let them know I’m not dead and will be posting in the future. The updates in this post will cover Astrophotography, General Photography, and Amateur Radio.

 

Astrophotography

Well…as with writing, I haven’t been doing much of this since Wickahoney. It sucks, too, because the weather has been great for it. It hasn’t been a total loss, though.

I did crawl out of my warm bed to see the Blood Moon of the wee hours of 8 October 2014. I actually went outside in the driveway and watched it for a while before it dawned on me to grab my camera. So, I quickly went back in, grabbed the camera, and got back out. I don’t know what I was thinking, but I started taking pictures handheld. Trying to keep the ISO down in order to eliminate as much noise as possible, I was obviously shooting hand-held exposures that weren’t going to come out nice and sharp. Eventually I actually realized that and started bracing against the porch. That kept slipping, definitely operator error, so I moved to the car. The angle of the windshield was perfect but I was still getting blurry images due to the speed at which the moon moves. As I started dialing in for that by increasing the ISO and getting better and better pictures…my battery went to bed. By that time, the moon was emerging from totality so I just stayed up and watched the show a while longer then headed back in to bed.

Lessons learned: Get the friggin’ tripod, it’s only 30 seconds into the house and back out. Wake up more and think things through. Don’t be stubborn about the ISO, for stuff like this bump up the shutter speed, you’ll get better images that way!

On the plus side, I can now state that I have seen, personally and with my own eyes directly, with binoculars, or with a telescope all but one of the planets. The only one I’m not able to say I’ve seen with 100% confidence now is blue Neptune. Pluto doesn’t count, even though I keep thinking of it as a planet. Plus Pluto is so far away that I’ve got a snowball’s chance in hell of seeing it in person. Mercury, Venus, Earth, Mars, some asteroids, Jupiter, Saturn, and Uranus I’ve all seen now. Hold the Uranus jokes, please. Maybe this year or next year I’ll bag Neptune as well.

With Neptune having a magnitude of 7 to 8, I think I now have the necessary tools to locate it. I just have to watch for it to pass near something I can easily identify in the night sky and triangulate off, something that will help me restrict the area I search. The setting circles on my Celestron Classic C8 should really help with this hunt as will the GoTo capability of my Celestron Nexstar 102GT. Provided, of course, that I orient them properly.

Speaking of the Celestron Classic C8, I have the piggyback mount attached to the OTA (Optical Tube Assembly) now. This will let me mount my camera on the C8 and use the telescope to guide the camera. I should be able to get some nice long exposures even with the 400mm now.

General Photography

The only time I did any intential photography in this period was while on vacation in McCall, Idaho. As usual, we went to Charlie’s Gardens to see it and myself with the intent of doing some photography.

This time I got some really nice images of various flowers, and I admit to being pleased with many of them. I was trying to do macro flower photography and I actually took several hundred pictures. Some I took to try and stack for a greater depth of field and some I took to try different perspectives. The best ones, though, were those I simply took to practice macro photography.

Picture of a small blue and yellow flower against a blurred background of green leaves.

A macro of one of the flowers at Charlie’s Gardens, McCall, Idaho.

I also attempted to take the necessary pictures to produce a multiple image of each granddaughter, of my daughter and her daughters, and of her husband. For various reasons that I fully understand in hindsight, the results were dismal: late in the afternoon the light was changing too rapidly, and my depth of field was too shallow. Of the six shots in each sequence, only one is really in focus, the rest are just out of focus. Perhaps not enough to matter to others, but to me that whole project should be tossed. I’ll probably still assemble the images and deliver them to my daughter, but I’m definitely neither happy with nor proud of the result.

Amateur Radio

I’ve done no operating, but I did manage to get a nice, clean installation of my Yaesu FT2500M and FT857D radios in my new to me 1992 Blazer. Power and feedlines are mostly out of sight and are definitely not in the way of passengers or driver like they were in the Geo Tracker.

Image shows two radios mounted in the center area of a 1992 Blazer Silverado.

The FT-2500M is mounted right under the dash while the FT-857D is mounted to a bracket that is in turn mounted to the sloping front of the center console. The Chorus (described in text later) is in the console cupholder.

Antennae for 2m and 70cm are roof-mounted mag mounts: a 5/9 whip for the FT2500M and a combo 2m/70cm for the FT857D. For a clean HF antenna mount, I bolted a front receiver to the frame of the Blazer and was thus able to simply slide in my stinger-mounted 40m Hamstick, using the entire mast assembly intact from the Geo Tracker. I was even able to keep the tow hook that was there. I couldn’t use the rear receiver as the antenna would constantly be in the way of opening the rear and there’s also the need to use the rear receiver for towing the trailer.

This shows the receiver mounted where the tow hook bolts on as well. The L shaped receiver with the condujit pipe mast is the same assembly formerly used in my rear receiver of the Geo Tracker.

This shows the receiver mounted where the tow hook bolts on as well. The L shaped receiver with the conduit pipe mast is the same assembly formerly used in my rear receiver of the Geo Tracker. The mast has no noticeable impact on the headlights lighting up the road.

There’s no APRS install yet as I’ve got to figure out where to put the GPS receiver for best reception. I don’t want it just sitting there on the dash against the windshield. The Geo Tracker’s ragtop was ideal for the APRS setup I had. The Blazer has a metal roof, as you’ve probably deduced from the use of the mag mounts, so mounting it right up there against the roof isn’t an option. I’m thinking of mounting it to the Blazer’s roof rack, but we’ll see.

I also found a small device, the Chorus in the cupholder of the interior image above, that I had forgotten about. That device was originally intended to help me with lipreading but it’s useful for other audio detecting. Supporting a vibrating external transducer and having a mic input, it allows me to connect it to the radio’s audio jack and feel when the squelch breaks without having to look at the radio. I’m hoping it will help me locate and identify CW frequencies in the area. I’m also hoping that with it I’ll be able to eventually learn to “listen” to CW by feel.

Along with that approach, I’ve got a friend attempting to recreate an arm-mounted device I read about that was only referred to as “the Thumper” by some deaf CW operators back in the 1960s. I’ve mentioned the Thumper in an older post.

One of the things I’d been trying to figure out how to do recently was to somehow limit the FT857D scanning to just the 40m CW frequencies. I finally found out it has that capability in the form of Programmable Memory Scanning. Yes, the manual does refer to it as PMS, and so does the radio’s LCD: “press the [C] (PMS) key”. I’ve already made some groaner jokes about that elsewhere and won’t repeat them here. Anyway, it goes to show checking the owner’s manual every so often is worthwhile.

I’m hoping to use this feature to monitor for CW activity without having to scan through all the other frequencies I’ve got programmed into the FT-857D. I’ll be doing this monitoring mostly during my commutes to and from work but hope to also play with it up in the Owyhees. With any luck, eventually I’ll build up a list of reliable CW frequencies for this area and start imporving my CW skills.

I have no intention of transmitting CW while driving. I’ll pull over to operate, but I very much want to get my CW skills up and running so I can have reasonable QSOs and be able to just “listen” to CW exchanges while driving like you listen to the AM/FM radio or your cell phone. I’m not into contesting, but I am interested in chatting and this is a skill that would be very welcome during my Owyhee explorations, which often are in areas with no cell phone service.

That’s it for now. I’ll try and post more frequently again.

Hamming Hijinks

5 March 2014

Between being plain silly and the weather, my attempts to construct a multi-band end-fed wire antenna were nothing short of silly. And the ending was one of those “DUH!” moments, too.

I had built my new mobile mast  specifically to attach a 20-40-80m end-fed wire antenna to for use up in the Owhyees and other locales where I like to roam for photography and day drives. Intended to be used as a NVIS and inspired by comment exchangess with Denis Gagnon, VE6AGE, it would be deployed by tension or laying on bushes.

I go out and move the vehicles around so I’ve got a playground for this work. The sky is grey with black here and there, but I’m hoping to get enough time to work things out before any serious rain hits. A little sprinkling here and there won’t hurt me.

I hook up my tape measure and the end of the wire spool to the top of the mast. I back away from the vehicle, unrolling wire and watching the tape measure. When I get to 17 feet, I cut the wire for the 20 meter section. My plan is to very carefully trim it down, little by little, until I have 1:1 SWR or pretty close. I trim off the end of the wire and bend it around a small bungee cord. That I connect to the larger bungee cord that’s connected to a fixture on the house. With the freshly cut wire nicely tensioned, I move to the back of the vehicle.

There I hook up my trusty antenna analyzer. I set the frequency to 14.070 MHz and check the SWR. Pretty high, so I go out to the end and unhook the wire from the bungee. I trim it back, strip the new end, wrap the exposed wire wround the bungee cord, and hook it back up. Back to the vehicle I go, and check the SWR again. Good, it’s dropped.

Back and forth I go, back and forth, back and forth until finally I’m getting in to 1:1.4. Getting there! My next cut makes the SWR go back up, though! What the @#)$(&@#$&*(!! happened?!?!?!

There was no doubt about it. To get a lower SWR, I’d have to go to a higher frequency, which meant I’d cut the wire short. I’d been so careful to only cut a little at a time, except at first when I had such a high SWR. After that it’d been steadily dropping. The analyzer still read 14.070, so I hadn’t messed that up.

Curious about the length of the wire, I grabbed the tape measure and walked it out to the end of the wire. 13 feet 2 inches. WHAT?!?!! The calculated length was 16 feet 6.7 inches or so. I’m standing there staring at it, wondering how that happened.

I’m sure you see the error of my ways. It was about then that I realized what an idiot I’d been. If not, I’ll let you try to guess what happened…refer to the 4th paragraph from the top.

See it?

It was then that I looked down at my hand, over at the antenna mast, and started cussing myself out. The tape measure was still connected to the top of the mobile mast, along with the wire. I hadn’t been measuring an end-fed long wire, I’d been measuring a center-fed long wire and trimming one end of it. The tape measure, as most are, was metal, was connected to the top of the mast along with the wire, thus making the overall electrical length of the wire I was trying to trim much, much longer. Plus, I’d left the tape on the ground once I cut the wire at the start of the whole process.

Right about then it started to rain and I had to gather up everything and get my meter, tools, etc. under cover. I also called it quits for the day, as it looked like it was going to be quite a while before the rain stopped.

Which turned out to be a good thing.

I hate to waste wire. So I started thinking about a way to salvage that 13 feet, somehow. I could always use it to hook up something, sure, but it now had a ring lug soldered on one end.

I was sitting in the living room watching TV with my wife when it popped into mind what I could do with it. I could turn it into a 10m end-fed wire antenna. Actually, I could turn it into the first part of a 10-20-40-80 meter end-fed wire antenna, hopefully. I did some calculations and it turns out the 10m wire would be closer to 10 feet. Definitely salvageable. That became my plan, then, and I worked out the lengths for the four wire sections to make the 10-20-40-80m antenna. Satisfied, I put the new design away, planning to work on it the next day I had a dry evening.

I told my wife about all this as we were getting ready for bed, having a good chuckle at myself and happy with how I’d salvaged the situation. All definitely wasn’t lost yet.

I’d gone to bed and was laying there dozing when it hit me.

Suddenly, I was wide awake, wondering how I’d missed the obvious.

The whole point of this antenna was to have a single, convenient, easily portable end-fed wire antenna that would work well as a NVIS on HF. IF amateur radio satellites used it, IF I had helped other hams build fox hunting yagi antennae with it, IF I had just suggested a similar idea to another ham for his grounding radials for his portable field antenna, then WHY the heck hadn’t I thought of this earlier?

Remember that metal tape measure?

It’s marked with feet and inches. Why couldn’t I simply connect that to the mast, unreel the necessary length of tape measure, and have my antenna that way? Need a lower frequency? Let more tape out. A higher frequency? Wind up the necessary amount of tape.

Plus I can use the tape measure to measure things.

The only downside is that I can’t just deploy the whole thing, suspend the far end, and quickly change bands via jumpers.

The next evening, I hooked the end of the tape measure to the mast and unreeled 16 feet 7 inches of metal tape. Properly suspended by bungee cords, and more or less parallel to the ground, I hooked up the antenna analyzer and measured it on 14.070 MHz. A little fiddling around with the length of the tape and I eventually had a SWR of 1.3:1. Not bad, at all.

So, I unreeled out to 28 feet. After fiddling with the length, I wound up with 30 feet 2 inches for a nice 1.1:1 SWR on 7.0704. PSK31 on 40m anyone?

As you can see from the pictures I jammed my 100 foot steel long tape with a tie wrap. I plan to build a wedge I can jam in there. The neat thing is, I could still, with some effort, wind up tape without having to remove the jam. That allowed me to slowly zero in on the lowest possible SWR, provided I started long.

I’m off to the store this weekend to buy me a nice long tape to toss into the car and leave it there as my end-fed, completely adjustable, totally tune-able to any desired frequency antenna. As long as I don’t need more than 100 feet of radiator I’ll be fine. Once I have the new tape, I’m going to work out each PSK31 frequency along with a couple others of interest and create a lookup table. All I’ll have to do is park, attach tape measure to mast, look at the table, unreel to the desired length, insert jam, hang that end of the tape measure, and get on the air.

Nice. Compact. Portable. Fully adjustable. Pretty near an ideal wire antenna.