A - We do not promote "gain" numbers for the Ventennas. Here's why -
The "gain" of an antenna is measured in decibels (dB), and is a ratio of signal strength using the antenna of interest compared to some standard. Up until about 1990, manufacturers used a half-wave dipole as the reference standard. Frequently, a manufacturer would say an antenna had " 3.7 dB gain over a dipole" (or "3.7 dBd"). This was simple and easy to understand.
But, some manufacturers thought that bigger numbers would sell more antennas. So, the standard was changed to an "isotropic source." An isotropic source is a purely theoretical concept...you can't make one. It radiates a perfect signal in every direction — the pattern is a perfect sphere.
Compared to an isotropic source, a dipole has a gain of about 2.6 dB. Thus, that antenna which had 3.7 dB gain over a dipole, now has a gain of 6.3 dB over an isotropic source (or "6.3 dBi")! That certainly sounds better, doesn't it? But, there is no difference in the antenna!
So, instead of touting gain, we offer our "No Discussion" Warranty. If you buy a Ventenna and don't like it, send it back within the first 60 days and we'll refund your purchase price plus your shipping cost.
To (finally) answer your question, a Ventenna is essentially a vertically-oriented dipole, and performs similarly. Being outside and stealthy are the important considerations.
Q - Can I get longer/shorter cable; different connector; inside/outside feedline?
A - You certainly can! As a special order, the Ventenna is available with any length of RG-59 coaxial cable you require and with any connector that you need. In addition, the feedline can exit through the side (as our standard Ham Ventennas) or through the bottom (as our Commercial Ventennas).
The frequently-requested options are on the price lists. If you need something not listed there, please call us at 888-624-7069, or send us an email to sales [at] ventenna.com.
Q - Can I get a different type of coax cable on the Ventenna?
A - The coax we use for the pigtail attached to the Ventenna is Belden type 8240 (RG-58). We use this because it is the correct size for the routing and connection inside the Ventenna. We cannot use a larger diameter cable. This is why the pigtail is short - to keep the amount of this higher-loss cable to a minimum. We could use a similar-diameter teflon-type coax, but there would be no significant difference in the loss performance, and the cost would be dramatically higher.
Q - What type of cable should I use between the antenna and the radio?
A - The answer to this question is "It depends!" Basically, you want to use the lowest loss cable that you can afford for the extended run of RF cable.
Some considerations - Smaller diameter cable has more loss than larger-diameter cable. But, the type of dielectric (the insulation between the center conductor and the shield) also is a major factor. And, any coax has more loss at higher frequencies than at lower ones, So, the determination is complicated. To help you understand the difference between different cables, here is an excellent coax cable attenuation calculator.
For reference, RG-8, RG-214, and RG-8X are some common, easily obtained cables to check. Other types may be more expensive and harder to find.
Q - What are the RF exposure considerations for the Ventenna?
A - OSHA and the FCC have published guidelines for RF exposure, and the ARRL has a comprehensive write-up on the subject available, although the "official" information can be difficult to comprehend. We have tried to make the subject a bit more understandable here. This is recommended reading for everyone using radio transmitters.
Q - What is the Ventenna Warranty?
A - We believe in the quality of what we sell and back it up! Our policy is simple: if it breaks or stops working, we will replace it. Period. Plus, if you buy a Ventenna and don't like it, send it back within the first 60 days and we'll refund your purchase price plus your shipping cost. In more than ten years, we've had ONE Ventenna returned! Here is our official Warranty statement.
Q - Who are some of Ventenna's customers?
A - We've had some interesting customers over the years. Among them are:
Central Intelligence Agency (CIA)
Federal Bureau of Investigation (FBI)
Department of Defence (DoD)
Federal Emergency Managment Agency (FEMA)
The Russian Government
The Government of Bahrain
Q - Is the Ventenna patented?
A - Indeed it is! The Ventenna patent (5,349,362) encompasses 18 separate claims for the design, configuration, and concealability. If you'd like to see our patent, click here.
Q - Why isn't a 6m, HF, or CB Ventenna available?
A - The basic concept of the Ventenna is to not be noticed - to "hide in plain sight." At VHF frequencies, the Ventenna is about 36 inches long. Many homes and businesses, especially newer ones, have vent stacks about this size, so, up to this length, Ventennas don't usually raise any eyebrows.
However, as the operational frequency decreases, the antenna becomes much longer. At 6 Meters, the antenna would have to be 10 feet long. At CB frequencies and lower, the antenna would be 20 feet or longer for the same efficiency. That certainly doesn't fit the "stealthy" profile we're looking for!
Some folks have suggested just putting in loading coils to lower the frequency. But, if we were to reduce the length by inserting coils, we would sacrifice bandwidth. A 36-inch long antenna for CB or lower frequencies would have a very narrow bandwidth (as little as 25 kHz) and be a very inefficient antenna.