Radio operators typically want to get the best performance and range out of their antenna systems. VHF and UHF  propagation is typically line of site, so the common thought to increasing range is to increase the antenna height. For the most part this works, but when you look at the numbers, you will notice an decreasing rate of return for each foot that you increase in your antenna’s height.

To calculate range for an antenna such as the KB9VBR J-Pole antenna, you can use this simple equation to determine antenna’s receiving range over a flat surface: range in miles = square root of height X 1.42. An antenna mounted at 30 feet should have a theoretical range of 7.78 miles. Of course terrain and surrounding buildings and landscape can greatly affect this number.

You’ll notice that doubling the antenna height doesn’t automatically double the range. If you wanted to double the range, you’ll need to triple the height. In order to get greater and greater return in antenna distance, we need to increase the antenna height quite an appreciable amount.

It’s also worth noting that terrain makes a big difference in communications. These numbers are for a flat surface or over water. If you live in a valley or on a hilltop, you’ll find that your range will vary greatly. There are more sophisticated calculations that you can make to figure your antenna’s height above average terrain, and how high you’ll need to be to effectively communicate based on terrain. Increasing your transmitter’s power can also affect the range, using a 50 watt transmitter vs a 5 watt transmitter can affect distance greatly.

But this formula should give you a great ballpark estimate of the range or distance your antenna will experience.

On Sunday January 22, 2012, the US Postal Service will institute an across the board rate increase for their shipping and mailing services. This rate increase, which will see first class postage increase by 1 cent, will also affect the shipping of Priority Mail packages. Consequently my shipping rates will increase slightly on that day.

The good news is that all antenna orders before the 22nd of January will ship at the old rate. If you are looking for a 2 meter J-Pole antenna, or one of my other amateur radio, public safety, and scanner antennas; you can order now and ship at the existing rate, saving you a little bit of money.

This is the first shipping rate increase I’ve had to make in over three years. Even though the Postal Service has increased their shipping rates on an annual basis (as have all shipping services), I’ve been able to keep shipping in line by closely analyzing my shipping costs and keeping costs in line the best I can.

Thanks again for your continued business, it is greatly appreciated.

As I write this, we are in the midst of one of the most mile winters that I can remember. Our snow cover in northern Wisconsin is only inches deep and in fact I have quite a few bare spots on my lawn. With temperatures soaring into the 40′s (in January, no less) the snow really doesn’t have a chance.

Although the warm temps and mild weather is putting a damper on the outdoor snow activities, you can take advantage of the warm temps and beautiful sunny days to inspect and upgrade your antenna systems. Instead of climbing the tower when its unbearably hot, use this time to put up a new 2 meter J-Pole antenna. Or replace an aging antenna with something newer and better performing.

Did you get a new scanner or amateur radio transceiver for Christmas? Get it on the air with a base station antenna. Our J-Pole antennas make great scanner antennas, especially for the VHF public safety spectrum. My MURS J-Pole antenna is an ideal public safety antenna and will also perform double duty transmitting on the MURS radio band. Same story with the Marine Band J-Pole antenna. This antenna is tuned for the VHF marine band, but has enough bandwidth to cover the VHF public safety spectrum.

As the weather stays mild and the skies clear, use this time to enhance and upgrade your antenna system.

Merry Christmas from KB9VBR J-Pole antennas. I hope your holidays where Merry and Bright and that Santa Claus brought what you wished for. Maybe your Christmas wish was to contact rare DX, peace on earth, or to receive a bright new  shiny rig under the tree. I can’t help much with the 2nd wish, but if you received a new VHF/UHF radio for Christmas, this is the place to come for a new antenna.

The KB9VBR 2 meter J-Pole antenna is a great choice for your new VHF 2 meter rig. If you received a handheld radio, read my post about how to connect your handheld radio to an external antenna. New hams often start out with HTs but find the range limiting. A good antenna makes all the difference between making the contact and getting lost in the noise.

Merry Christmas once again, spend some time with people you love. After that, if you need a diversion, head on down to the ham shack.

Are the hams in your family naughty or nice? Are you or a loved one expecting a radio under the Christmas Tree. A KB9VBR J-Pole Antenna makes a great Christmas gift for your loved or ham buddy across town or across the country. I’ll ship your antenna to any US address for no extra charge. Buy your gift here and don’t worry about getting it delivered.

But, you gotta hurry. Christmas day is Sunday December 25, 2011 so today, Wednesday December 21, 2011 is the last day I can take orders and still get them under the tree.

Merry Christmas everyone!

Our community, Wausau and Marathon County, Wisconsin is in the process of converting their analog radio system over to a narrow band digital radio system. Marathon County has about 130,000 residents and covers an area about the size of the state of Connecticut, so this is no small task. The new system has several microwave links and simulcast transmit and receive sites to effectively cover the area. Unfortunately a slew of technical issues is causing the transition to take longer than necessary and driving up the costs.

But this post isn’t about the technical difficulty of the new radio system, but instead illustrating the fact that when the new system goes on the air, my primary antenna I use for scanning, a KB9VBR J-Pole Scanner antenna will still work with the narrowband digital frequencies. Instead of moving to an 800MHz trunked system, the county is still using their existing VHF frequency allocations. I’ll still be able to use the same antenna and feedline, but I’ll have to upgrade to a P25 digital capable scanner.

Antennas are antennas, regardless if they are receiving an analog or digital signal. So the antenna you buy today to monitor analog frequencies will work tomorrow when they transition to narrow band and digital communication modes. As long as they stay in the same frequency range that the antenna is tuned for, the antenna will still work.

I often receive inquiries if my antennas can be used with handheld or HT radios. The simple answer is that if your radio has a detachable antenna, then yes you can connect it to my J-Pole antennas or another style of antenna.

Connecting your HT to an external antenna is a great way to extend your range of the handheld, especially if you are using your handheld in a remote location. The duck antennas that come with most handheld radios are not very efficient, most have none or even a negative gain. They are designed for portability and not efficiency. If you wanted to set up a field station at a public service event, or even use your HT as a base radio, then you will need a better quality antenna, such as the 2 meter J-Pole antenna.

Handheld radios these days usually have an SMA or a BNC antenna connector on them. The J-Pole antenna uses an SO-239 connector on it, which mates to a PL-259 connector. The PL-259 is the standard connector for 50 ohm coax cable. You will need an adapter to connect your HT to the coax cable. Radio Shack does sell a BNC to SO-239 adapter. The part number is 278-120 and this should be a stocked item for most stores.  I know they also have an SMA to SO-239 adapter, but I was unable to find it in their online catalog. Radio Shack employees are not often well versed in the little components that they carry, so if you have the part number, your shopping experience will go better.

My favorite go to place for adapters and connectors is Tower Electronics. This online retailer can also be found at many hamfests in the the Midwest. When I run into them at a hamfest I’ll often pick up a variety of connectors and adapters that I may need for a future situation. They have both an SMA to So-239 adapter and an SMA to SO-239 adapter with a three foot jumper. For the SMA connector, I recommend getting the adapter with the jumper. This will take the stress off your HT’s connector and prolong it’s life.

These adapters and connectors will let you connect your handheld radio to standard 50 ohm coax cable so that you can use the J-Pole antenna with your handheld radio. This will not only increase the range of your HT, but also give you solid communications when using your handheld as part of a field station at a public service event. Start collecting adapters and keep them as part of your EMCOMM, emergency communications go-bag kit.

MURS or the Multi Use Radio Service is a license free radio service designated by the FCC for short range business and family communications. MURS has five channels in the 151 – 154 VHF MHz range that can be used. MURS has some distinct features that makes it very useful for a wide variety of communications:

• No license is needed for MURS communications
• Voice or data can be transmitted on the MURS frequencies
• 2 watt transmitter power limit for base and handheld communications, but no limit to antenna gain
• You can attach external antennas to a MURS radio, like the MURS J-Pole antenna.
• Antennas must have a max height of 20 feet.
• There are a wide variety of MURS radios available, like the popular Motorola RDM2020 handheld unit.

The best thing about MURS is that it is license free, so you can hand just about anyone a MURS programmed radio and not worry about the user having a FCC license.

What types of activities or groups are using MURS radios? MURS is great for search and rescue operations, coordinating volunteers at parades and community events, business operations and facilities, and personal communications. The radios are inexpensive and the MURS band is relatively uncongested, so it makes a great choice when other radio services may be loaded with communications.

Since MURS radios can use external antennas, but the antennas are limited to a 20 foot height, you’ll want to select a high performance antenna to maximize your signal range. The MURS J-Pole antenna is a great choice as it is lightweight, affordable, and very sensitive. The antenna’s wide bandwidth covers the entire MURS frequency range and the low noise floor will easily pick out a weak signal from a distant MURS station. Mounted at the 20 foot height, you can ideally expect a 5-10 mile range with your MURS radios, although surrounding buildings and terrain may affect performance.

Need more information about the Multi Use Radio Service to determine if its a right choice for your needs? Check out this MURS resource.

Merry Christmas and Happy Holidays! My antennas make great Christmas gifts and I will drop ship them to any US address.  Wouldn’t you love to see a KB9VBR J-Pole Antenna under your Christmas tree? If you want your antenna shipped as a gift to a friend, just leave  me a note during the checkout process of who and where you want the antenna to go. I’ll even include a nice little card wishing the recipient a Happy Holidays.

Christmas day is Sunday, December 25th. The last day to order one of my antennas for guaranteed Christmas delivery is Wednesday, December 21 by 11:59pm central time.

Thanks again for your support, I greatly appreciate your referrals of my antennas to your friends. Have a most excellent Holiday season this year.

Michael, KB9VBR

I recently received a Kenwood TM-281A two meter amateur radio transceiver as a door prize at last month’s state ARES/RACES conference. Well, last week I finally got the radio hooked up and put a few frequencies into it. General impressions: this is a very nice rig with clear audio, easy to use functions, and sensitive receive.

I’ve owned quite a few 2 meter and 2/440 rigs over the years from all three of the major manufacturers: Icom, Kenwood, and Yaesu. Each has their peculiarities and differences, but with everyone putting out quality products, it really all boils down to features and capabilities. With that being said, the Kenwood TM-281 delivers and easy to use, quality product. The radio is ruggedly constructed with a large heat sink along the back and bottom. I like the fact that the heat sink isn’t on the top of the rig. My Icom 2100 has a top mounted heat sink and that think filled up with dust and gunk after a couple of years of mobile use. Buttons on the rig are lit and big enough to push while on the road. The radio also has a very nice volume control and channel selector with detent clicks. Pushing the channel knob also access the setup menus.

Setting it up in my basement shack, I had it connected, programmed with one frequency and on the air in less than 10 minutes. The instructions are well laid out and the index quickly brought me to the section on where to program memories. But you can just as easy us it in the VFO mode as it has automatic repeater offset shift and enabling tone control was straightforward. The only thing I found a little cumbersome was using the direct entry keypad on the microphone, but it seems like this is a downfall on all the radios these days.

Audio on the Kenwood TM-281 is excellent, although compared to the audio on my primary base rig, the Kenwood TM-V7A, it seems a little tinny. The TM-V7a has a larger, top mounted speaker that give a fuller, richer sound. The TM-281′s speaker is smaller and front mounted, which is an advantage when the radio is mounted in a vehicle. Since I didn’t mount it in my car, I don’t know how the smaller speaker fares when up against the vehicle noise while on the road.

Out of the box, the Kenwood Tm-281 puts out 65 watts of power on high and 25 watts on low. This is great for mobile use as we usually run our mobiles on high power anyways. I’d love to see a more energy conserving 10 watt mode for low power base station use. I hooked the radio up to my 2 meter J-Pole antenna that I use for my secondary VHF and digital station. This antenna is mounted on a mast at about 10 feet. I had no problem picking out other mobile signals within at 10 mile radius on the repeater’s reverse frequency. The radio also has a built in weather alert function, and I scanned the weather band, picking up about 4 transmitters in a 60 mile radius. This rig definitely has a very sensitive receive. It also wasn’t bothered by my other rig while transmitting on a second 2 meter frequency.

The radio has up to 200 memories, but if you use the 6 character alpha tags for your memories, you will be limited to only 100 memory channels. 100 memory channels seems a little small for a radio in this day and age, especially if you travel a lot. My first 2 meter rig, an Icom 2100a, offered that many channels 10 years ago and I had it filled pretty quick.

All in all, I’m impressed with the Kenwood TM-281. It’s a highly capable, affordable amateur radio rig, and would recommend it to anyone looking for a starter radio or second rig for the shack or vehicle. I have  a feeling this one will eventually wind up in the wife’s car.