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During the recent devastating Black Forest fire in central Colorado, my good friend Gain vhf mobile radio antenna colleague, Randy, had great difficulty maintaining solid radio communications through our local repeater from his home. Our local hams kept the repeater very busy during the days of the fire relaying the Gain vhf mobile radio antenna information gleaned from emergency response links, commercial sources, AREA and RACES volunteers, and more.

It was a valuable resource in our community for rapidly disseminating fire information. His home is located just on the leeward side of a hill from the repeater that is about 7. After the fire emergency, Randy decided it was time to upgrade his station for more reliable operations in the Gain vhf mobile radio antenna area. Gain vhf mobile radio antenna he plans a future station upgrade to a more powerful mobile-base transceiver, he sought first to improve his home antenna such that he can use the HT in the short term and integrate a mobile-base transceiver later.

Commercial purchase or homebrew? I use three or four different ones in my home and in portable station Gain vhf mobile radio antenna of various flavors. Most commercially available antennas are going to provide great performance and even greater convenience! In virtually all cases you can simply buy-and-install with only the requirement of connecting a feed line to the antenna.

If you want to open the wallet instead of the tool box, a commercial antenna is your best choice. There are many simple designs provided by a whole world of Gain vhf mobile radio antenna to choose from. Yagi directionals for VHF ops are great projects, if you seek that directional boost in signal gain for your situation. With a homebrew solution you can save some money, but be prepared to invest the time and effort necessary.

And remember, every antenna is a compromise, so carefully check out the design and performance reports before finalizing your decision. Single band or multi-band antenna? With multi-band radios now so readily available to hams, the majority of folks are likely to desire a multi-band antenna with which a single feed line can be used. Ditto for only, or 6m band ops.

Consider the local radio resources available to you and how you wish to use them, and then decide what band capability your station and antenna require for those operations. Trees can help conceal antennas or even serve as a growing, green mast!

Antenna location? The type of antenna you obtain and even the specific model or design will likely be influenced by your chosen mounting location. Gain vhf mobile radio antenna hams who live in covenant protected neighborhoods like to mount antennas in the attic to keep them out of sight.

If you plan to mount your antenna outdoors you may wish to ensure you get a sturdy model that can withstand high winds and that provides moisture protection at the coaxial Gain vhf mobile radio antenna feed point. If you mount in a tree, be sure the motion of tree and limbs will not damage or dislodge the antenna.

Location and antenna selection are closely coupled, so think it through before you purchase or brew. Antenna gain? Depending upon your situation you may need a little boost in your effective radiated power, or the effective signal strength from your antenna. Many antennas provide signal gain, boosting the effective transmit power at the antenna. Comparison of isotropic, dipole, and Gain vhf mobile radio antenna patterns of signal strength.

Antenna gain is defined in comparison to a reference antenna. Recall that a 3 dB increase or decrease is a factor of 2 comparison. So, an antenna offering 3 dBi will provide double the signal strength in its main lobe transmission pattern as compared to the same transmission with a theoretical isotropic antenna that radiates equally in all directions, like a sphere.

If your antenna specification says 6 dBd, it provides main lobe gain 4X that of a dipole antenna. The signal pattern from such antennas tends to be disk-like in a horizontal omnidirectional pattern, degrees around the antenna.

So, the signal strength that the theoretical Malawi sex sugar mummies pictures antenna spews in every direction Gain vhf mobile radio antenna Woman model with guitar spherical pattern is vertically squeezed into this disk pattern, providing relative signal gain.

A dipole antenna produces lobes with the strongest signals at right-angles to the radiating element orientation. The weakest signals are out the ends of the radiator. So, a dipole has gain as compared to the spherical isotropic antenna pattern. Pay attention to whether the gain is expressed as dBi or dBd when comparing antenna performance, and realize that a lower gain figure in dBd may actually be better than a higher figure in dBi.

Compare apples to apples, oranges to oranges. Lastly regarding gain, if you choose a directional antenna with high gain figures, you will usually want to plan for a mounting scheme that allows pointing, or rotating, the antenna.

Additional Considerations? Other antenna factors that you may want to consider include the height at which you mount your antenna generally, higher is betterthe mounting method you plan to use mast, tree, attic clamp, strap to chimney, etc. Impedance: It is very important to select coaxial cable Gain vhf mobile radio antenna a characteristic impedance that matches your transmitter output and your antenna feed point impedance. How do you know what to get? As signals travel along the conductors they will be attenuated.

Higher frequency signals will have more loss in the transmission line than lower frequency signals, and different designs of coax cable will impose different magnitudes of loss overall. The most common comparison metric is loss in decibels per feet of cable, like the table here.

Gain vhf mobile radio antenna, lower loss cable types are more expensive than higher loss — you get what you pay for. But if you have a short run of only a couple dozen feet to reach your antenna, the loss may not be that significant and you can save your money. If you have a longer Gain vhf mobile radio antenna, more than 50 feet, you may find it advantageous to pay a little more and preserve your effective signal strength at the antenna.

Further, you should also consider the gain of the antenna you select along with the loss imposed by the coax. Narrow gauge coax such as RG or RG is low profile and quite flexible. It requires smaller holes and it fits corners. However, as noted in the table above, narrow gauge cables tend to impose higher signal losses. Larger gauge coax, such as RG-8,or LMR is much more noticeable and is usually stiffer and somewhat more difficult to work with.

However, the larger gauge cables tend to offer the lowest loss figures. Additionally, some of these larger diameter cables are produced in flexible varieties, such as Belden F7. It combines very admirable loss figures with high flexibility for ease of routing, but it is limited in its power handling capacity to about watts.

Consider the coaxial cable routing for your potential antenna locations and identify the best combination of cable type for location, routing, and loss. Almost every conceivable combination is available as single adapters or as short cables with differing connectors on opposite ends.

With this connector you can readily attach a home antenna system to an HT radio that uses the SMA connector, or dispense with the adapter to connect the PL feedline connector into a base station transceiver.

Compliments of Arrow Antenna. So, he was willing to trade off high gain for low expense. He also had to consider his neighborhood HOA covenants that prohibit highly visible external antennas. His first preference was to try an attic antenna over his garage and close to Gain vhf mobile radio antenna home office operating position. This option provided the shortest coaxial cable length requirements as well, but it was unclear what kind of attenuation he would get from his roof materials.

His backup option was to mount a low profile rooftop antenna, strapped to a chimney box, positioned such that it was not obviously visible to surrounding neighbors. This higher, exterior location should provide improved performance over the attic option, if needed. The attic option imposed a height restriction on the antenna of 66 inches maximum, and if the rooftop exterior option was necessary Randy wanted a low profile antenna.

A J-Pole offers about the same gain performance as a half-wave dipole. It is a simple, inexpensive antenna, and this specific antenna stands about 60 inches high.

We would try the J-Pole in the attic location first and see if the performance was acceptable in that configuration, and we would go for the more difficult rooftop location only if necessary. Since he planned to use his 5 watt HT initially with the antenna system and would not have a higher power transmitter until later, keeping the transmission line loss low was a key consideration.

Using the fully available 60 feet of this cable we estimated the loss to be approximately 1. Given the additional attenuation by the roofing materials, we were dubious that the attic solution was going to be sufficient! Although the N-connector tends to offer better performance for UHF, this was not an option for this antenna. Once again, a bit more loss was to be expected for the UHF transmissions! Still, we would just try it and see!

Finally, Randy used a cable adapter as pictured above with an SO connector on one end and an SMA connector on the other to attach the antenna to his HT. He routed the coaxial cable down into the garage and connected to the HT. It worked! Randy hit the repeater with a moderately Gain vhf mobile radio antenna and perfectly readable signal.

We traded positions so that Randy could hear the signal from his new antenna, and he deemed it quite good enough. Subsequently, Randy installed the J-Pole with more permanent mounting to a rafter in the attic. He routed the coaxial cable above the ceiling and down the garage wall, and then into his office with a nice cover plate on the interior wall. Some Antenna Considerations.

This connector combo is very commonly found on mobile and base station antenna connections, and it serves very well in the HF and UHF ranges.

You can obtain PL connectors for most of the coaxial cable gauges, although they usually will not be coupled with the narrowest gauge cables such as RG or RG


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