Saturday, March 29, 2014

Contest weekend and the Hustler 6BTV vertical

Just a rainy spring day.

 Well, here it is a rainy spring day up here in the pacific Northwest portion of WA state and I will not be turning the radio on this weekend due to contest activity. The CQWPX SSB will be tying up the bands with lots of noise and QRM as all the big gin stations try to out do each other in contacts and points. Don't get me wrong, i have nothing against contests at all, and participate in them myself at times, but mostly Morse Code (CW).

I just can't understand SSB.

 The biggest problem with SSB contests is that I just can't copy voice on the HF bands. it has something to do with my hearing im surte, but unless a station is strong i jsut can't understand what is being said. When you get thousands of stations all calling at once it makes it even worse for me. That is why I decided it would be a good weekend to work on the Hustler 6BTV.

The hustler 6BTV.

 The Hustler 6BTV is a 75/40/30/20/15/10M trap vertical (6 Band Trap Vertical) antenna made to give a low takeoff angle for HF frequencies. By adding traps the antenna is only a 1/4 size of what a full size antenna woul be while still giving great performance. it is small at 24ft, which is small compared to the Diamond CP6AR Vertical
Diamond CP6AR hf vertical antenna

Murphy stops by for a visit.

 The main problem I am having right now is that 15M and 30M do not want to tune up anywhere near a decent SWR (Standing Wave Ratio). I was given the antenna so i can't complain too much. it also included the Ground plate for the radials and the tilt over base which makes it SOOO much easier when tuning or doing maintenance on the antenna. The rain storms don't help much either. I may end up having to take the 15M and 30M traps apart and double check that i didnt mix them up somehow. Since the antenna is used, the labels for each trap are well worn and unreadable.
 
 If anyone knows an easier way to test the traps other than taking them apart and counting the rings of witre be sure to let me know.

Tuesday, March 11, 2014

Lots of rain and the Hygain beam saga

Finally some sunshine out here.

No sightings of Noah's ark yet.

Been looking at once again working on the Hygain TH3jr beam that I put up last year. Everytime I have made plans to work on the antenna it has rained like they days of Noah. Rain coming down so hard that the sound of it pounding on the roof would drown out the sound on my TV set. Rain so hard that it would bounce several times before settling into a puddle. Think instant standing water on the roadways.

 I can almost hear Gene Kelly on the roof.

)

The Hygain TH3jr is still a decent performer.

 Even with the Beam not performing as good as it should it has been a good performer for me with all the 10M openings lately into Europe from the Northwest portion of Washington state. Usually if I can hear them I can work them with 100 watts.

The TH3jr beam has been an excelent performer for me the last year or so. Even with the SWR's slightly off. Switching between the Hygain beam and the Cushcraft R5, I can hear the difference in signal strength, even with the R5 at the same 35ft height as the beam.

Yet another beam saga.

 I did receive a TH7DXX something or other last winter from a ham that was getting rid of antennas that I still need to get up in the air. In order to put the bigger beam up I will have to stiffen up the mast that I am using, and also install a rotor to turn the antenna around. Right now I use an Armstrong rotor to turn the beam around to different headings. The TH7DXX is MUCH bigger and would require a larger mast as well. Right now I am using a 35ft telescoping pole with the TH3JR beam and spin it by hand.

$60 bucks for little plastic caps.

The TH3jr beam needs to be rebuilt as well. Need to eventually spend the $60 bucks for the little plastic covers that go over each end of the traps on each arm. They are severely dried out and cracked.
Really, $60 bucks for little pieces of plastic Hygain?

Thursday, January 23, 2014

HF ham radio antennas

Why is a good antenna important for communications.


Putting together a ham radio station is a fun and very rewarding first step for proper communications. So why do so many people spend massive time putting the shack together only to neglect the antenna system and put up some sort of compromise antenna expecting good results.

The importance of the antenna.


The antenna that is used by an amateur radio operator will either make or break your system. If you spend all your time putting together a ham shack and neglect the antenna then you will be highly disappointed. It is better to spend most of the time putting together a good working antenna and use 2nd hand gear. It doesn’t matter if you have a 10K dollar radio and a crummy antenna: No one is going to hear you.

When it comes to the antenna system that you use, no two stations are alike. You have to experiment around with a design that works well for you. Some stations are constantly trying new designs to get the best possible signal to the desired location. The point is you have to find what works for YOU and YOUR station.

If you live on a small lot or are limited to one antenna then sometimes you have to use a compromise antenna like the G5RV multi-band design. The G5RV is a decent compromise ham radio antenna and is very popular in the amateur radio circles, but most operators that are new to the HF bands put this sort of antenna up expecting exotic DX when there are so many other designs that can be used. The G5RV is not an all purpose, all out DX antenna. It is a compromise between usability and antenna limitations. It works poorly on ALL bands with an antenna tuner, but it is still better than NO antenna.

The G5RV antenna was originally created by Louis Varney as an all purpose HF wire antenna. It is 102ft in length with a tuned vertical section made of ladder-line. When used with an antenna tuner it is an acceptable HF antenna.

What is the best antenna for HF.

HF: High Frequency. 3MHZ to 30MHZ.

In every antenna article that you find on HF antennas, they always have the same glowing results after they are done describing the design they used. The last paragraph will go into how comparing different designs they find the new one is always louder and stronger, or that they were able to break through some DX (Distant station) pileup on the first try after putting up the new antenna.

Plug and Play electronics.

With the plug and play attitude and replaceable consumer electronics that are on the store shelves available, amateur radio has followed suit with radio equipment that is for the most part non fixable by the average user. You simply buy a radio, hook it up to an antenna and get on the air. When it stops working you simply replace it with a new one. This idea can be found with the popularity of the Baofeng UV-5R series of radios that currently sell for under $30. They are a commercial dual band handheld radio that are usable on the VHF/UHF amateur bands. If they break it is no big loss to the consumer. Although these radios are perfectly acceptable they are very inexpensive and not fixable by the average consumer.
Another clue is the availability of pre-made wire antennas on the market. Most of these can be made very simply with parts purchased online or your local hardware store. In some circumstances it is perfectly acceptable to buy a ready made antenna if it is an exotic design or requires pieces that can not be readily made, or if a person is unable to make a wire antenna for other reasons.
Get on the air.

Whatever method you choose to get an antenna up and get on the air, nothing compares with the satisfaction of building your own antenna and making it work. Whether you decide to build one of the exotic designs or a simple Dipole or G5RV, building an HF antenna is the first step in gaining the confidence you need to move further with Amateur Radio and start experimenting.

See you on the bands, and 73

Wednesday, January 22, 2014

Building a simple Ham radio antenna

Building a simple ham radio antenna....
Or, Someone got an antenna book for Christmas...Can you guess who?1


So, you want to try your hand at building your first antenna for ham radio use, but are unsure just where to start. All the tutorials you find online and all the math involved can be confusing and often frustrating, causing you to lose interest and move on to something else. It doesn’t have to be this way of course, but in this plug and play society that we live in it is sometimes easier just to spend a few bucks and purchase a pre-built antenna. The trade-off is that you gain a sense of accomplishment after you build your first antenna and find out just how easy it can be.

HF, or High Frequency is from 3 Megahertz to 30 Megahertz. Ham radio operators have privileges to transmit on designated frequencies from 3 to 29.7 MHZ in the HF spectrum.2

A dipole is the simplest ham radio antenna you can build and get's you on the air fast!



When looking at all the different designs that are available it is best to start off with the simple designs and move onto some of the more exotic antenna's later. A good starter wire antenna is a simple dipole3 that can give you the confidence you need to try other antenna's. A simple dipole antenna is just a ½ wavelength piece of wire, cut in half and fed with either coax or ladderline. It doesn’t have to be any more complicated than that really. Their are a LOT of other factors to building an efficient antenna system but a good start is with a simple ½ w dipole made of wire. By using the formula:

468/Freq=Length (It really is THAT simple)

You can come up with the basic length to get you in the ballpark of a working antenna system. Building an antenna for 80M in the CW portion of the band you would just divide 468 by 3.55 to get roughly 131.8ft (Total length). I personally add at least 1ft on each end for tie offs to the insulator also. From this point depending on ground conditions and configuration of the antenna, and type of feed-line that you use (Coax or Ladder-line) you should be very close to a working antenna.

Getting fancy.

If you want to get more advanced and have a more efficient antenna then you should try using Ladderline to feed the antenna. Not only does ladder-line have less loss equaling more power to the antenna, but it's characteristic impedance more closely matches a wire antenna, coming in at 400 to 600 Ohm. Ladderline is a bit harder to work with and depending on how close you have it to other objects will affect it.

If you want to improve on the dipole design even more you can add a 4:1 balun at the feed-point of the antenna. This will stop the vertical section (The part hanging down from the wire) from radiating any energy, making more of your signal come out the antenna.

And that is one of the simplest antennas that will get you on the HF bands and making contacts. It works best if at least 1/4w above ground, but will work fine if you can't achieve this.(For 80M this is about 66ft off the ground) Just be sure to set it up at least high enough to keep it out of reach so no one grabs a hold of it. (While your transmitting).


1 Reference for most of this material comes from “Practical antenna handbook 2nd Edition” by Joseph J. Carr.
2 HF band privileges range from LF (Low frequency) up into the Microwave frequencies.
3 A Dipole antenna has a omni-directional pattern, radiating equally in all directions.   

Tuesday, January 21, 2014

Diamond V2000a antenna



Looking at improving communications here at radio station W7DTG, and one option that I have is picking up a Diamond V2000A tri-band vertical antenna. I had one of these before and it was a great antenna for working local 2M/440 communications. Even with a low power radio like a Baofeng UV-5R and the proper connectors the Diamond V2000A has a great signal for FM work on the VHF/UHF bands.

According to the Diamond page, it is a ½ w lopsided dipole on 6m, a 2X5/8 wave on 2M and a 4X5/8 wave on 440 MHZ. With 6.2 Dbi on 2M and 8.4 dBi on 440 it has potent signal for punching through anything in it's way.

The Diamond antenna that I owned before was mounted on a 6ft pole in front of the house, and I was able to easily work repeaters and simplex stations 20 miles away with good signal quality. Now that I live even farther away from town I need a way to get back into 2M activity. I am currently using a dual band j-pole on a 20ft pole that works ok with marginal signals into the repeater.

From the diamond page over at TheronAtPlay.

The Diamond V2000A: a no-compromise compromise antenna

Although it is a compromise antenna the Diamond V2000A will still deliver a potent signal on 6M in the 52MHZ to 54MHZ range and also covers the 2M and 70cm amateur radio bands. the threads for the radials are 10/32 inch, making it easy to replace or modify using standard threading. Some have experimented with changing stock radials for radials made for 6M with very little change on the 2M and 70cm bands.


From my own personal experience with this antenna I know that it performs well and has a tri band capabilities on 6M/2?70cm. Even mounted on a low pole it worked well for me.
One other option is to experiment with wire designs that are similar to the Diamond V2000a. Although it wouldn't be as pretty it should work OK.

Now where did I leave that antenna book.....

Cutting your first dipole

Your first wire antenna.


SO, you finally broke down and built your first ½ wave dipole antenna, but the darn thing isn't working where you need it to. How do you know where to add or subtract to the length of the wire without trial and error?

Enter the math!


Just like everything else that has to do with ham radio, eventually you are going to have to break out the calculator and do some equations. Just like you did to find the initial length of the antenna for the band you wanted to work on. But don't worry because this math only causes a few gray hairs. Get the aspirin ready and dig out that old calculator, because here we go!

In an earlier article we discussed how to measure the approximate length of a dipole antenna using the formula:
468/Freq = Total length of antenna /2 (for each half)
468 / 7.050 = 66.4ft (Total length) /2 = 33.2ft
(Don't forget to add at least an extra foot for tie-offs)

Remember to measure twice and cut once, so you don't make any mistakes.

As stated earlier, this equation WILL get you in the ball park, but it is by no means a simple solution for every ham. Factors such as ground, antenna height and configuration also factor in. You can have the antenna strung up flat between two trees, an inverted V that has a single apex in the center with both legs drooping down at 45' angles, or even as a sloper that angles down with one end up high and the other 10 to 15ft off the ground. Each configuration will change the characteristics of the dipole antenna.

OK, so how do we know how much to cut off from the antenna to give us a low SWR and make it work properly.

According to the “Practical antenna design” handbook 2nd edition. by Joseph J Carr.

1. Calculate the length required for the upper end of the band.
2. Calculate the length required for the bottom end of the band.
3. Calculate the difference in lengths for the upper and lower ends of the band.
4. Calculate the width of the band in Kilohertz by taking the difference between the upper frequency and the lower frequency.
5. Divide the length difference by the frequency difference; The result is is in Kilohertz per unit length.

HUH?

But wait, don't run off screaming trying to wrap your head around that concept just yet. It is really a lot easier than it sounds, and just requires a little bit of math. Basically you are just measuring the difference between the top end of the band and bottom end of the band. In this case we could use 80M as the example. Since the top end is 4.0MHZ and the bottom is 3.5MHZ that gives us 500khz to work with. And if you do the equation 468/Freq:
468/4 = 117ft
468/3.5 = 133.7
You have 16.7ft to use. SO far so good right?

This is the really really really hard part, so time to put those thinking caps on. Just take the 500Khz and divide it by the feet, in this case 16.7 which equals 30khz per foot.

500/16.7 = 30

Wasn't that difficult. And their you have it, a quick down and dirty way to figure out how to quickly cut your antenna to resonance using simple math. But how could you use this to make the antenna work at your location ?

This is really fun so far isn't it? If you cut your dipole and find that it's working great in the center of the 80M band but you need it for the lower CW portion and need to lengthen it, this formula will tell you how much to add to the antenna to make it work properly.


Building your own antenna will give you a tremendous sense of accomplishment and get you on the airwaves making new friends from all over the world.

P.S. If you really do not want to bother making your own dipole then purchase a wire antenna at Amateur Radio Supplies.
*HINT* Use CouponCode 73 for an additional 10% savings.