Archive for category Antenna Stuff
Antenna switch label
Posted by jeff in Antenna Stuff on February 5th, 2010
After working some 40m PSK this evening, I found I had to move the switch positions around a little. With the updated configuration, I can work someone off the Vee, and then make one switch movement to get to the vertical for DX. Doesn’t sound like much, but in a QSO or contest, this allows for quick change in antenna take-off angles. The label is a custom label template in Microsoft Visio.
The chores before the storm…
Posted by jeff in Antenna Stuff on February 5th, 2010
With the upcoming snow storm that’s predicted to hit the Northeast US in the next few hours I decided to move my Ameritron RCS-8V antenna switch to it’s permanent home so it doesn’t get buried under the supposed 18″ of snow. I used my new RG8/U cable to connect it into the shack. I swept the 110 foot coax run with .3 db loss at 1.9mhz and 1.1db at 29.7.
DLARC Hamfest
Posted by jeff in Antenna Stuff, Shack Stuff on February 5th, 2010
Tonight was the 2010 DLARC mini hamfest which brought a great turn out to our monthly meeting. I’m pretty psyched to have come home with about 300 feet of RG8/U. Coax is a non-stop necessity in this shack… At least for the time being. All in an effort to convert from my RG8x to support an upcoming amplifier purchase. For those not in the know, RG8x is a smaller diameter 50 ohm coax cable that serves the HF world very well, but usually has a maximum power rating of 300-500 watts.
..the festivities continue..
Posted by jeff in Antenna Stuff on January 28th, 2010
The morning of the last NAQP (North American QSO Party) I put up an 80 meter inverted vee using an Alpha Delta Delta C center insulator hoisted 50 feet up a tree in my backyard. Seeing as how successful my results were on 80 meter, I added a 40 meter vee about 8 feet below it. The balun of choice was from Hy-Power Antenna company. KU3X, Barry the owner happens to be a fellow club member of DLARC and offered a bunch of information on antenna design.
Since I now have 3 antennas in the backyard and only 1 cable running to the house, running outside in the rain or snow to flip antennas got old quick. Hence my recent purchase from a ham on QTH.com. I was lucky enough to acquire a used Ameritron RCS-8V, 5 antenna remote switch for a very discounted price. I ended up using 100 feet of CAT5 cable as a temporary run between the control box and relay box outside. When my permanent cable arrives next week, the plan is to bury it and a run of RG8U coax out to the relay box. Ultimately a 40 meter delta loop will also makes it way to this switch as well as a 40/80/160 meter off-center dipole around 60-70 feet.
For now I can switch between to 2 vee’s and vertical from the laziness of my own chair.
Antenna switch panel
Posted by jeff in Antenna Stuff on November 2nd, 2009
After building my desk rack a few months back, it’s time to actually start using it. My plan was to have anything shared between operators to be place in the middle of the desk or in the rack. One of these things is antenna switching.
Starting with 2 Alpha Delta switches I already had, I went out and bought 2 3U blank rack panels. I drilled out the panels for screw mounting, control switch and GAS fuse. I have enough room now for 6 switches. I also created labels in Microsoft Visio for the panels.
The idea is to assign an antenna to each individual switch, which is where you would select the radio. On the next row, you would select your antenna on a specific radio switch.
Alot has changed at N3QO….
Posted by jeff in Antenna Stuff on October 29th, 2009
In the course of the last month while talking with Jay (N3OW), I’ve been introduced to Hex Beams. I initially was introduced to them a while back after seeing the $500+ kit from DX Engineering, but didn’t think much of it. If it wasn’t a dipole, yagi or vertical it wasn’t of optimal design… Or so I thought.
After reading a number of reviews of the design from various vendors, I decided to venture in building one myself. I went out with a minimal budget and bought 1/16″ plate steel, U-bolts and 12′ crappie poles. This would serve as my $250 prototype. I had found that my implementation of the design was weak and quite fragile in nature, but it did make it up on the roof in one piece with elements for 20 and 15 meter. Also to note, there are 2 styles of Hex beam. The original places the reflector in an opposing M-shape from the W-shaped driven element. In 2007 a ham discovered that the reflector could be reconfigured to form the outer shape of the hex which would ultimately increase front-to-back ratio and make the antenna broadband in nature, giving us a much lower SWR.
I had found this antenna had more front-to-back ratio than the Cushcraft MA5B I had just taken down. At most I had seen 12db f/b on the Cushcraft, and a minimum of 18 on the hex beam. At peak I had found approximately 24db while working a station in Ireland.
My first contact on the hex was Chris (9Y4D) in Trinidad who reported back a 59+10. A signal report I had never seen at 100 watts. I would later work another station in Italy with the same report. I was sold.
It was time to make the design more permanent and it was time for the Cushcraft to be put up for sale. The money for the MA5B completely covered the upgrade costs for the MaxGain Hexbeam spreader kit. This kit is a MUST! Don’t even bother with the crappie poles. They are just that, crappy. I broke 2 of them on the ground just trying to get the spreaders under tension and then trying to get it up on the roof. Spend the $140 and go the right route. You won’t regret it. I also found the original base I had built had warped under the tension of the spreaders. For another $30, I rebuilt the base, way overkill than it needed to be. Regardless, it won’t be a part which will fail.
After 2 hours of rebuilding, restringing and then raising the antenna, I was back on the air with 20-15-10m capabilities, with a very flat and acceptable SWR Sweep.
Below are photos of the build and SWR sweep images.
crickets…..
Posted by jeff in Antenna Stuff, Shack Stuff on September 23rd, 2009
WOW! It’s been a while since I’ve posted. Even with this blog being purely about ham radio, alot has been going on for me within the hobby. Here’s the update:
1) The Pocono Hamfast was an unfortunate bust. We drove 70 miles from our QTH in Pottstown, PA, to be faced with a “less than mediocre” hamfest. Only 1 vendor listed on the flyer was there and they were only selling power poles and HT cases. Honestly this has to be the worst one I’ve been to yet, which was quite unfortunate.
2) With the upcoming 2009 CQ RTTY contest this weekend (Sept 26-27) I’ve enabled digital modes on Laurie’s Heathkit SB401/301. I took a hint from another ham using the HD15 phone patch as a computer interface for a DVK (digital voice keyer), I used our SB-630 station console for PSK/RTTY/SSTY instead. It was quite simple to do even though their appears to be a 550 ohm impedance difference between the computer and the phone patch interfaces. So far so good. Posts with photos coming soon.
3) I recently aquired an IC-2200H for the truck. Even though it’s only 2 meter, it gives me better D-Star capabilities down the road. My interest in D-Star has been waning as of late. Packet loss and “R2D2′ing” gets old quick, especially when you are a member of net operations. Thoughts of selling my 91AD for this reason have been plaguing me lately. See my recent D-Star post.
4) After spending an afternoon with my local radio club (DLARC) and speaking to a fellow ham, I’ve been introduced into the world of Hex Beams and Cubical Quads. I’ve never really investigated these types of antennas as they’re not considered to be the “conventional beam”. I’m happy to say after doing a bit of research, I’ve started building the base of the antenna and am quickly aquiring the parts to build the rest of the antenna. It seems all the commercial vendors want $100 for a hex base. I really wanted to go with the DX Engineering base, but decided to go completely homebrew instead and spent $30 at The Home Depot last night on parts. As I build this thing I’ll post my experiences and photos as I progress.
Shock Hazards and crashing computers.
Posted by jeff in Antenna Stuff, Shack Stuff on September 5th, 2009
Be careful with those vintage radios kiddies! While completing the finishing touches on my station grounding system yesterday, a got good little buzz coming off of the antenna feed line off the YL’s Heathkit transmitter. The power switch was off, which I always make sure to do whenever I’m making any connection changes to it. It felt like a shock from an electric outlet just not as intense. After I had her station grounded, the voltage differential went away, which is what I expected.
Here’s what I discovered:
Upon disconnecting the RG8u feed from it, I had no differential between the ground bus nor the cable shielding. This indicates a proper ground from the bus to the radio, which is where the cable shield is connected to.
After lifting the ground strap from the radio so the radio appeared to “float” electrically, I still had no difference in ground. I soon remembered that I previously hooked an audio line between her receiver and her computer so she could decode and monitor RTTY. When I pulled the audio cable, a 60 VAC differential appeared between the ground bus and the radio’s chassis.
Here’s why:
The Heathkit radio is powered with a 2 wire AC cord unlike the newer radios with external power supplies feeding 12 VDC to the radio. The DC power supplies bond the negative side of the circuit to their chassis ground, which in turn is then usually fed via a 3 prong power cord with ground. Since the Heathkit is essentially floating via AC, they probably attached chassis ground to the neutral side of the power feed. So when you compare the difference between a station ground and chassis ground, 60VAC appears, one half of a 120VAC house feed. Hopefully your not comparing the difference with your hand. It’s definately an attention getter.
One of the things to keep in mind when you start introducing voltage differentials and computers, you run the risk of damaging computer components. Think about it for a moment. The radio is floating electrically and your computer is grounded. Now you attach a 1/4″ to 1/8″ wire from your radio to your computer. While your pushing that connector into the computer’s Line-in jack, it’s possibly contacting other non-ground pins on the audio card, unleashing the voltage difference between the radio and the audio driver circuits in the computer. POOF! Your sound card or motherboard could be woofed. Mine didn’t, that I’m aware of.
Lesson learned: Ground your components before interconnecting them.
Additional station grounding.
Posted by jeff in Antenna Stuff, Shack Stuff on September 4th, 2009
Today on the way home from taking my RHCE (RedHat Certified Engineer) certification test (I passed), I stopped over at the local hardware store and picked up a roll of Yorkshield 106 PT. It’s a 12″ by 20ft roll of .020″ copper flashing. I created a grounding bus under the desk and interfaced it into the grounding wire coming up from the outside ground rod. It’s a similar product as the Georgia Copper .022 rolls, but a bit cheaper. I created 2″ straps that connect the radios to the ground bus.
RF Choke Coils
Posted by jeff in Antenna Stuff on August 31st, 2009
Since Laurie and I got our radios back on the air at the new place we found we’re generating interference into the computer speakers both up and downstairs. Remembering a trick from the 6BTV’s installation manual I promptly made 2 RF Choke coils where the transmission line comes back into the house. One for the beam on the roof, the other for the vertical in the backyard.
I made one of these for the 6BTV at the antenna feed point that is buried under the radial field right at the radial plate, but what I was lacking was a choke on the source point. Taking the remaining 6″ PVC pipe from the first choke, I made two 8 inch pieces. Then I drilled a set of holes on each end of the PVC to secure the RG8x. Next I wrapped the cable around the PVC 10 times then secured the opposing end. Lastly on the back of the coil on either end of the start and finish of the wrap, I drilled a hole on each end and secured the whole coil with another tie-wrap.
I immediately transmitted a test pattern via SSTV at 100 watts generating 100% duty cycle and our interference problems are completely gone and it took all of 5 minutes to build each. Now onto the cable TV issue…. 
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