3/4 Exterminator II VHF TV band III DAB+ omnidirectional antenna

 4,99 239,99

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SKU: 1KW max VHF omni Categories: ,

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 5,99 227,00

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 5,99 406,00
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 4,49 42,99

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The Exterminator is our most powerful true omni-directional vertical VHF Broadcast Antenna to date.

Why is it so great?

The Exterminator® II can be mounted on the top of the tower and can thus give perfectly circular omni-directional radiation pattern. Its gain is comparable with 2-bay dipole array. However, you cannot mount 2 dipoles on the top, you can only mount them at the side of the tower. And when you do this you can’t have circular radiation pattern as the tower is blocking the signal in certain directions. This antenna is perfect and makes perfect sense where you have space on the top of the tower.

Designed from the ground up the Exterminator® II slams the competition. Produced to exacting standards using state of the art electrical and mechanical designs resulting in superior performance and long service life. The high grade construction and DC short protection will provide peace of mind to stations who want to Stay On Air and withstands the toughest environments. Arrives fully tuned and easily assembled the Exterminator can be installed on your tower or mast in a matter of minutes. Tuning to a new frequency takes only minutes thanks to our wideband gamma matching system.

When measured against a standard 1/2 λ dipole the Exterminator® II delivers a massive 5.15 dBi gain across the entire BAND III TV VHF Band. All RF connectors are PTFE components with specifications that exceed required ratings. Once tuned to your frequency the Exterminator® will never go “out of tune”.

Remember to include your desired frequency during check out, write it under comments. You can always tune your antenna alone with SWR meter and included instructions.

Technical specifications:

– Frequency range: 175-225 MHz
– Impedance: 50 Ohm
– VSWR: 1.0:1 @ Resonance
– Gain: 5.15 dBi
– Connector: “N”
– Weight: ~3.5 Kg
– Max Power: 900-1000W
– Polarization: Vertical Omni Directional
– Feed: Gamma
– Tuning: Pre-Tuned / Whip Adjusting

Electrical Data:

– Type: 7/8 λ coaxial Vertical
– Radiation (H-plane): 360° omni directional
– Polarization: Vertical
– Gain: 5.15 dBi
– 4MHz Bandwidth at S.W.R. 2:1:
– S.W.R. at res. freq.: ≤ 1.5:1

Mechanical Data:

– Materials: T6061 Aluminum, PTFE, Stainless Steel, PVC
– Wind load / resistance: 400N at 250 Km/h / 230 Km/h
– Wind surface: 0.2 m2
– Height (approx.): 2,5m
– Weight (approx.): 3m
– Mounting mast: 40mm


Tuning instructions:
Although antenna comes pre-tuned it is recommended that you re-check the SWR before putting antenna into service, nearby objects can slightly de-tune the antenna!

1. If you received your antenna pretuned extend the two telescopic sections until the two black marker rings show.
If you are retuning to another frequency extend the antenna as shown below (loosen screws and extend the 2 telescopic parts).
If tuning for around 225MHz: Extend fully
If tuning for around 200MHz: Extend 50%
If tuning for around 175MHz: Extend about 25%

2. Mount the bottom part of the antenna to the intended metal pole and tighten with screws firmly

3. If you received antenna pretuned, do not loosen gamma rod.
If this is a new untuned antenna or if you are re-tuning loosen the gamma strap so that the gamma rod can move in and out with a bit of effort. Now set the rod so that it is about 1/3 in the black gamma match tube.

4. Connect RigExpert SWR analyzer (AA-230 or better), power it up, press 4 for SWR measurement. (read the PS below if you do not own one).

5. Move center frequency to frequency of choice (use Freq – and Freq + buttons), set range to about 20MHz for a start, you can reduce range later when you get close to the frequency of choice.

6. Press OK to start measurement. The curve minimum needs to be close to zero at the desired Frequency.

7. Change the length of the antenna until you get best SWR at desired frequency.

8. Change gamma rod position until you get best SWR at desired frequency.

9. Repeat 7 and 8 until you get minimal SWR reading possible.

10. Tighten all screws

11. Check SWR again. If needed, correct.

12. You’re done!

PS: If you don’t have antenna analyser feel free to use SWR meter as well, however do this at minimal power that still makes it possible to get a decent reading out of your SWR meter and at the same time does not endanger the output stage of your transmitter. Never read SWR off the LCD display of your transmitter, USE A REAL SWR meter or antenna analyser.

Important: Due to large size and irregular shape of these packages the website often gets shipping cost wrong. Also sometimes we have to use wooden case which adds about 100 euro to the cost of antenna. For exact shipping cost please contact our sales department, be sure to give them your exact address and they will quote you shipping.

Recommended accessories: Grounding kits can be purchased here, they ensure lightning protection. They should be installed at the antenna, at the tower base and at the point of entrance into transmitter building. Also use self-sealing tape on connectors, it fuses into rubber and protects moisture from entering your coaxial cable and antenna system.

Some history/background:
This antenna is based on the old AVANTI SIGMA 4 or AV-174 design. An antenna first produced by Avanti, (The Antenna Specialist Co.) and cloned by many under various names. Lately it has been sold by SIRIO as Vector 4000. Antenna is most commonly seen on the CB band and can be found under various names like: Sigma IV, Vector 4000, CTE saliut lw 150, Targa BT 104, Q-82, etc. Though there are examples since 1996 available for other bands up to VHF region like FM broadcasting. Almost every present day CB user has heard of the antenna. In fact many have used or are still using the antenna today.

Most of the FM broadcasting band versions are actually produced for CB band and just modified to work for FM band radio. CB radio products are usually quite low-quality low-cost and they use very poor quality gamma match which is perfectly good for CB radio but when used at high power at 88-108MHz these blow  fast. Those also often use cheap plastic connectors and parts, again fine for low power and CB but not 24/7 high power VHF broadcasting. Pretty much all of them use low-cost cast heads. Competition in CB world is very stiff and every cent counts.

Our VHF FM broadcasting band Exterminator antenna is also a version of the AVANTI SIGMA, but it has been built from scratch for FM broadcasting and comes with high-grade CNC machined head. Antenna is fully built for VHF FM broadcasting and not a re-purposed CB version. Check the photos. Connectors are all PTFE.

If you run into guys who sell these antennas and claim that they invented them even though the antennas are identical to the old AVANTI SIGMA design just ask them for patent number and see them struggle as they won’t be able to produce it. Some of them put up fake websites and launch smear campaigns to attack their competitors. We don’t. Everything written above is true. You can and should read about this very interesting antenna here, it makes for an interesting reading and is highly recommended.

Yes, full 3dBd is possibly a bit too optimistic to expect but it gets pretty close to two dipoles considering there are no combiners and no harness cables. Also less parts to break. Perfectly circular omni-directional pattern is a plus as well as there is no shadow from the tower seen with side-mounted dipoles.  As this antenna is mounted on top of the tower it will likely be a bit higher than 2 dipoles would have been. All in all, our field tests indicate performance very close to two dipoles and in some cases exceeding two dipoles (shadow from the mast with dipoles).


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