Posts Tagged ‘amateur radio’
Antenna Ideas: Please Keep ‘em Coming!
August 16th, 2010 | 
Author: After last week’s plea for antenna ideas for my antenna restricted condo, I received a good number of comments both on and off blog. Thanks for those… great food for thought. That is why I enjoy our QRP community. We don’t hesitate to share ideas with one another.
This morning as I took my daily walk around the lake, I met our condo association president. He graciously is allowing me to sink a pipe that will serve as a base to set up my Jackite poles in the backyard. I will be able to pop a cap on the top and keep the dirt and water out and just slide my fiberglass poles into the mount and be on the air in no time. YAHOO… that is a pretty good solution for now.
C Pole Antenna by W0VLZ
But being the antenna tweak that I am, I continue to look for the best alternatives I can find. I’ve started to put together the parts for the C Pole antenna that Niel W0VLZ pointed out to me. He has a fine site with lots of good QRP info too.
So, do you have another idea that can top that one? Or maybe you have a thought for what kind of vertical setup I might use with the new mount?
I’m standing by for my next project assignment.
72,
Kelly K4UPG
First contacts with the Warbler
Olivia QSO with VE3FMC using a Warbler
Despite Summer not being the best time of year for 80m QSOs I have made a couple of contacts over the last two nights with the recently completed Warbler.
The first was a PSK31 contact with AE1Q who was about 285 miles away in Belgrade Lakes, Maine. The next was an Olivia 8/500 contact with VE3FMC in St Thomas, Ontario, about 325 miles away. Both QSOs proved to be tougher copy for the other stations as the Warbler puts out only about 2 Watts. However, they were successful QSOs and as can be seen by the picture above the Warbler receives well.
AE1Q gave me an IMD report which was -24 dB which is reasonable given the simplicity of the rig, but I would like it to be below -30dB.
I was fortunate and pleased that the second contact was using Olivia. This is a nice mode for QRP. For those wanting to try Olivia I recommend you read the information on the Olivia website by Gary, WB8ROL, including his QST article. Gary writes great articles (including one in the recent amateur radio edition of Linux Journal) and I have enjoyed a few Olivia QSOs with him.
Finally, if you do want to try Olivia or any multifrequency keying mode with the Warbler, you must remember that you are operating on LSB with the Warbler. Most digimode operators will be using USB so the frequencies will be reversed. The digimode software, Fldigi, offers a simple solution to this, you must select the “Rv” or ‘reverse’ button (see the lower right of the Fldigi window above, which is selected and green). You do not need to worry about this button if you just use PSK31 as it is symmetrical about a centre frequency.
Transformation of Radio Amateurs of Canada
Radio Amateurs of Canada is the national amateur radio organization here in Canada. It has just had its annual general meeting and coming out from this is a call for transformation. Peter of the RAC blog has sent me a link to the important news and I thought I would pass it on, as I know I have a few Canadian readers of my blog.
I am not going to comment here on what I have read, but will think about it and probably send my thoughts and ideas to RAC. Take a look at the proposal and if you want, send your thoughts to either RAC or post them here, it would be good to have an open discussion. If you are not a Canadian please still take a look at the details, as other national organizations may be heading in a similar direction, or have faced similar issues.
If you have thoughts and opinions on what you want from a national amateur radio organization please make a comment.
What Would You Do? Antenna ideas anyone?
We purchased our condo before I got back into ham radio. Like most in Orlando, we have antenna restrictions. I can put up portable or temporary antennas but cannot mount anything to the building permanently. I’d love to be able to get on the air without all the hassles of dragging gear to the porch, setting up an antenna and then tearing it all down again. It takes so much time to setup and tear down that it turns a few minutes of operating into a long process.
Here’s the layout I have to work with at the QTH…
The front yard view… I am next door down from the blue car
Preferred antenna site is the backyard
The buildings run north and south and these photos are shot facing due north. My condo is ground floor, second from the south end of the building. Yes, that is a big electrical transformer box and a major underground feeder line runs to it from the north.
I’ve used my Buddistick with some success but it doesn’t like being so close to the buildings and the swr is higher than when it is out in the open. I also have run a doublet inverted vee fed with twinlead but the north south orientation is not very favorable from my Florida QTH and sends most of my rf into the two buildings. My W3EDP works fairly well as an inverted L with my 20′ Jackite pole and I’ve used end fed halfwaves as slopers and inverted vees but again the directivity is not favorably oriented. I have a 3 foot magnetic loop propped against the wall but it is not working as well as I’d like yet. (i.e. the outdoor antennas work LOTS better so far)
Thought I’d ask ya’ll for some input.
Any outrageous ideas or thoughts for me? Send me a comment and let me know.
Thanks in advance for your thoughts.
Dual band rectangular loop antenna for 15m and 10m
The loop and the off-centre fed dipole at Field Day
This is the second article describing the two antennas that were used by the Carleton University Amateur Radio Club (CUARC) at Field Day 2010. The first post described an off-centre fed dipole with a 200 ohm feedpoint impedance. This post describes the second antenna a loop antenna that worked on two bands, 15m and 10m.
I like loop antennas. I have built large loops for amateur bands, as well as small loops for receiving (which are quite different to their bigger cousins) and have found both types perform well. They are less sensitive to local noise, so often giving good signal to noise ratios. As CUARC was to operate on 10m and 15m at the Field Day site I was considering a loop for one of these bands, however, which one? 10m could be fun if there was an opening, plus the antenna would be smaller than 15m. However, 15m would be more likely to be open. In searching the internet I came across a potential solution as KT4QW’s website who describes a 17m and 10m hanging loop antenna. The idea was simple and elegant, two vertical and rectangular loops fed from the same point, similar as to how multi-band dipoles can be fed from the same feedpoint (sometimes called a fan dipole).
I went about calculating the basic design. A full-wave loop’s total perimeter length is calculated by:
Length (in feet) = 1005 / f,
where f is the intended frequency of operation in MHz.
So for 21.3 MHz that would be a total loop length of 47.2ft and for 28.5MHz it would be 35.3ft.
To attain a 50Ω feedpoint the loop needs to be rectangular, with the longer length vertical. Studying J. Carr’s Loop Antenna Handbook and KT4QW’s dimensions the sides were close to being 1/3 of the total loop length for a vertical side and 1/6 for the horizontal side. So this then gave a design as shown below.
Dual band loop antenna for 15m and 10m.
To support the wire I bought two 10ft lengths of PVC piping. The inner support for the upper part of the 10m antenna was some thin wood. Both the wood and PVC were drilled with holes prior to Field Day. The wire was cut from a single 100ft roll and the whole antenna was built by CUARC members at the Field Day site on the day. At the feed point a 1:1 balun was used, an Elecraft BL2. The intention was to suspend the antenna from a single central point so the loop(s) could be rotated, using a line tied to one lower corner. However, we could not get enough height and clearance from tree branches, so we mounted it between two trees and it keep it static with the signal projecting in South-West and North-East directions.
The loops being connected to the balun by Gerry, VA3GLT (left) and Maria, VA3MMI, (right). (Photograph and copyright of Chris Weisner, VA3SM)
After construction the SWR was measured and found to be nicely below 2:1 for both bands (at least the lower part of 10m which is quite a wide band). As mentioned in the earlier post Maria, VA3MMI, brought a portable analyzer to the site on Sunday morning and the trace of the SWR profile is shown below. You can see the antenna has two nice dips in the SWR within the two bands. In an effort to see the usable bandwidth (below 2:1 SWR) the max SWR on the Y axis has be limited to 2.0:1.
10m and 15m dual band loop antenna SWR plot
To further examine the bandwidth of the two dips in SWR Maria, VA3MMI, set markers at the 2:1 points of the SWR curves. These are shown in the next two traces (one for each band). Both show good usable portions of the bands for phone, see the tables on the right of the trace. (Thanks to VA3MMI for the measurements and traces).
Bandwidth for 15m is 467kHz, starting at 21.1MHz
Bandwidth for 10m is 767kHz, starting at 28MHz
So, with the off-centre fed dipole and this dual loop antenna, CUARC constructed two antennas for Field Day that worked on 15m and 10m without the need of an antenna tuner unit. Performance was good on both antennas and I heard at least one comment that that we had a strong signal (we used 100W). During Field Day we made over 100 contacts on 15m and 16 contacts on 10m. Not bad, as for many of the CUARC members this was their first chance at operating on HF. It was enjoyable for the newly licensed CUARC members to build and then use the two antennas and to find both worked successfully. For me that was perhaps the highlight of 2010 Field Day.
Handiham World for 11 August 2010
Welcome to Handiham World!
From time to time we will feature a special operating skills essay, a short discussion of a topic related to building better operating habits on the air. There has always been a need to learn operating skills in amateur radio, but a great deal has changed over the history of radio, so the skills necessary must also follow this changing technology.
Some operating skills are very basic and one might think that they have changed little over the years. But remember, all of you old timers out there, newcomers to amateur radio now enter the hobby in a much different way than you did — or I did, for that matter. When I got interested in radio as a teenager, the thing to do was listen to short-wave radio. Many hours were spent listening on the air and learning about how to operate by simply hearing stations use their call signs, make contacts with other stations local and distant, or using those new things called “repeaters” on the VHF band. A licensing exam for a “Novice” license included a five word per minute Morse code exam. You were expected to get on the air and operate, learning as you went, for a specified time, after which you had to take the General Class exam or else find yourself another hobby. The system promoted the learning of basic operating skills from the beginning.
That is not the case today.
Newcomers to amateur radio today generally don’t even own short-wave receivers. Some may have listened to repeater traffic on VHF/UHF scanning radios, but their listening experience doesn’t come close to being the same kind of experience many of us had on the short-wave bands decades ago. The Novice Class examination is long gone from the requirements, as is any kind of Morse code exam. Now, don’t get me wrong; I am not complaining about these changes at all. Change is a normal part of life and we all realize that technology, including amateur radio, must change and evolve over the years. Unfortunately, even though our licensing process and structure has changed and technology has evolved radically, we have really not managed to figure out a way to teach basic operating skills before our newly-licensed hams press the push to talk button for the first time. Furthermore, the experience most Technician Class operators will have on repeater systems will not adequately train them in operating skills suitable for the HF bands. This has resulted in a situation where General and even Extra Class operators can be very weak in what we once considered basic operating techniques.
Fortunately, today we have more resources than ever to teach operating skills. The personal computer and the Internet offer vast resources and great potential. We can produce audio and video lectures to train people in basic operating. Radio clubs can have websites with “how-to” links. Amateur radio websites around the world offer help if only you can figure out how to find it. Helpers and teachers (Elmers) can connect with a person needing help using many different Internet tools, including e-mail reflectors, social networking sites, and Echolink-enabled repeater systems. VoIP systems like Skype can connect a newcomer needing some personal help in operating skills with an experienced operator on a one on one basis. The problem is that the application of this technology is scattered and inconsistent. Some radio clubs might be quite aggressive in helping their new members learn how to operate, while others do not. Some newcomers to amateur radio are able to figure things out for themselves, while others start out with bad habits and never seem to change.
What can you or I do about this?
Training excellent amateur radio operators begins at home. I have a mirror, and I look at myself in it every day. Sometimes I don’t like what I see and I know that I have to make changes. The same is true with my own amateur radio operating skills. From time to time, I need to just think about how I am doing things and about how I might do them better. Listening on the air to operators who really know how to conduct a net or snag a DX contact can really show me how other operators with better skills in these areas than mine succeed where I might not be doing so well. Listen, listen, listen. Think to yourself about how you can change your operating technique to more closely match that of the best operator you hear on the air.
Clubs and organizations can help, too. Offer club programs or even small study groups that promote operating skills. Do tabletop exercises, simulating on the air operation. Recognize good operating with awards. Use the Internet to promote good operating by including operating articles and tips on the club website. Develop on the air opportunities like practice nets where club members can develop their skills. The key to helping other people learn is to be helpful but non-judgmental. Learning takes place best in a non-stressful situation, so beginning with tabletop exercises where the mistakes people might make will not go out over the repeater system is a good idea.
I would like to hear some ideas from our readers and listeners about what has worked for you and for your local radio club as you bring newcomers into the fold. From time to time, I will be writing one of these short essays about some kind of operating skill. We will do our best to make a good operator out of each and every Handiham member. Some of you may have an idea for a unique and creative way to run a small operating skills class. Please share those ideas with us so that we can help make amateur radio better.
73,
Patrick Tice, WA0TDA
Handiham Manager
[email protected]
Toe Dipping & Antenna Modeling
I still think the tin foil does the magic!
After years of neglect, this analog era ham is willing to admit I only understand a bit about digital electronics. (Yep! Pun intended.) Well into the second week of my sabbatical leave, I have begun to plot out a course of study to get up to speed on the state of the art that I have so long neglected. Should be fun. There seems to be a good bit of open source help online these days and I have my trusty ARRL Handbook, Extra Class study guide, Antenna Handbook and assortment of other aids.
Any suggestions from the veteran techies out there will be greatly appreciated.
I am a learn by doing/hands-on sort of guy and find deep theory puts me into a semi-catatonic state after a few minutes. For me, it’s a whole lot more fun to take a stab at things and find out if they smoke, and it also makes a lot more sense when I can dink and tweak and see what that actually does. But since that is a bit expensive, perhaps I should learn how to use software like spice to do simulations? Any recommendations for how to learn this software?
Another area of toe dipping will be learning to do antenna modeling. For years I’ve looked at those charts and made little sense out of them. HA… I like to throw wire out and see what happens, but in the summer heat, maybe it is wiser to do a bit of modeling from my air conditioned den?
Thanks WX7S– Your site looks AWESOME for learning this stuff!
I’ll try to share some of the learning curve, but would love to hear from some of you that have gone before. Shortcuts are nice. WX7S your site looks like a great place for me to start! Thanks for the effort it takes to do that.
This weekend (Sat 14 Aug 2010) the Central Florida QRP Group will gather for breakfast at 0730 (Denny’s in Sanford, FL) and off to Sylvan Lake Park in Sanford, FL at 0900 EDT to operate. If you like cw and qrp or are just plain curious… come join us!
