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HIGH GAIN 3/4 wave FM omnidirectional antenna

 
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HIGH GAIN 3/4 wave FM omnidirectional antenna
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pcs
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Post HIGH GAIN 3/4 wave FM omnidirectional antenna Reply with quote
Guys, this is better than Comet and about as good as it gets
for a vertical. I definitely recommend this one!

HIGH GAIN 3/4 wave FM omnidirectional antenna

This is a redesigned standard 3/4 wave antenna to provide even higher gain. Preliminary testing of the antenna indicated a small increase in gain could be seen when the main radiator was made a little longer then the calculated 3/4 wavelength. This adds inductive reactance to the antenna and a few tenths of a db in gain once the gamma match has been retuned to 50 ohms impedance. We knew the increase in gain would be small by making the antenna longer and if we passed the optimal length, we would destroy the antennas performance altogether. We decided it would be worth the time to conduct further field tests and find this ideal length to extract every last bit of performance possible from any single omni directional antenna offered on this band. Using our exclusive formula we can now calculate the ideal length that provides maximum gain based on our customers frequency. High performance 3/4 wave antennas are not typically seen on any band because the 3/4 wave presents some interesting problems when it comes to impedance and angle of radiation. The typical 90 and 45 degree downward radials used on most smaller ground planes are capable of providing a good 50 ohm impedance but they also give a very high angle of radiation when used on the 3/4 wave. This wastes the added gain of the 3/4 wave by allowing a good deal of your signal to go up rather then out. Our innovative cone shaped ground plane structure on the 3/4 wave overcomes this problem and will refocus the energy so that it projects out into the distance and not up into space. A quick look at the picture showing the radiation patterns will make it easy to understand how this affects range when compared to other antennas. Our 3/4 wave has an impressive gain figure better then 6 db over a half wave dipole and more then 9 db over a circularly polarized antenna. The typical 100 watt LPFM station using a circularly polarized antenna has to run the transmitter at about 225 watts output in order to achieve the 100 watt ERP level because the CP antenna has -3.2 dbd. Since our antenna has a power multiplication factor of four times you would only need 25 watts of RF to reach the full 100 watt ERP level! This can provide a significant savings since many exciters produce 25 watts and would not require the expense of an RF power amplifier. The antenna uses a highly efficient Teflon insulated gamma match that eliminates any coils or matching transformers and allows us to shunt feed the 3/4 wave main radiator while keeping it DC grounded for added lightning protection. Another advantage this antenna has is it's ability to handle high power levels. The weakest link in the chain is the coax connector and our standard model offered in this auction uses a I am a spammer and this is my stupid link pin Teflon insulated weatherproof N connector recommended for up to 1 KW. A simple $50 upgrade using a 7/8 connector brings the power handling to 2.5 KW. For commercial operators seeking an excellent backup antenna that can handle full power we offer a special order 10 KW version. This model replaces the gamma match with a sealed Jennings vacuum variable capacitor and uses an EIA flange connector making it virtually impossible to burn out. Your antenna will be precisely tuned for your frequency and shipped assembled so you get a perfect SWR match. You simply slide the telescopic main radiator sections out of the base to the premarked spot, tighten the stainless steel clamps and connect the coax. Complete instructions are included for easy retuning in the field should your transmit frequency make a major change in the future. We have invested lots of research and development time into this antenna and are willing to stand behind it with a great guarantee. If the antenna you use now didn't cost thousands of dollars, replace it with ours. If anything should fail within two years send it back for free repairs or retuning if you would rather us do it. Give your signal some punch and try our antenna at no risk to you. Antena specs are as follows. Approximate height is 9 feet (depends on frequency). Wavelength is 3/4 wave. Gain over half wave dipole is better then 6 dbd. Power handling capacity is 1 KW on the standard model (2.5 KW with $50 upgrade) and 10 KW on the special order high power version. Bandwidth is 5 MHz. wide with a perfect 1:1 SWR at the center tuned frequency. Wind survival is greater then 100 MPH. Wind load is .7 square feet. Weight is 8 pounds. Radiation pattern is low angle omni with vertical polarization. Antenna is DC grounded for excellent lightning protection.


Features:

Frequency range: 88-110MHz (Tunable)
Impedance: 50 ohms
SWR: 1.1:1 max
Gain: 6 db over a half wave dipole, more then 9 db over circularly polarized antenna
Bandwidth: 5MHz, easily tunable
Max. power: 1000 Watts (with modification up to 10KW)
Length: 9 feet
Weight: Approx. 8 pounds
Connector: N
Max. wind speed: > 100 mph
Wind load: .7 square feet





http://www.pcs-electronics.com/en/products.php?sub=antennas#HIGAIN_vertical

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Tue Jan 18, 2005 1:22 pm View user's profile Send private message Visit poster's website
Antler
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Post Reply with quote
Is this antenna made by the "HIGH GAIN" antenna company in the states?


Wed Jan 19, 2005 3:55 am View user's profile Send private message
pcs
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Post Reply with quote


No, but it has high gain

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Wed Jan 19, 2005 11:57 am View user's profile Send private message Visit poster's website
erobertg
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Post Weather... Reply with quote
I thought that the 5/8 wave was an optimum for low angle radiation. This was the conventional wisdom for years. I wonder how this critical new design will hold it's SWR through snow, sleet and wide temperature variations.
Wed Jan 19, 2005 4:48 pm View user's profile Send private message
Antler
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Post Reply with quote
I will let you know how it works as I just ordered one of these.

Ref the 5/8s... Early on, I built a vertical J which works great but in my quest for MORE, I sent for and tried the 5/8s wave antenna. I found that my homemade vertical J easily outperformed the 5/8 wave by concentrating more of the signal on the horizon. My vertical J was better by a couple of miles, using "full quieting or no back ground noise" in my receiver as my reference for performance.


Wed Jan 19, 2005 5:05 pm View user's profile Send private message
pcs
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Post Reply with quote
I think this 3/4 is some variant of a J-pole so I'm not sure
how much better you can get. You can't do miracles, there's
only so much you can do with a vertical.

But its power handling should definitely be much better than
Comet.

Make sure you post your results here for everyone.

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Marko - PCS Electronics
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Wed Jan 19, 2005 5:34 pm View user's profile Send private message Visit poster's website
Dr. No
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Post HIGH GAIN 3/4 wave FM omnidirectional antenna, another view Reply with quote
In terms of money spent, you CAN get out FARTHER WITH LESS.
- DEPENDS ON HOW YOU DO IT.

The antenna is the place where you will get the most bang for your buck, IF you know how to bang. It's not the size of the hammer, it's the technique of the Carpenter

Lets say you have 200.00 to spend on antenna system, including shipping charges,
coax, TV mast pole + guy wire, etc.

Take the Comet. It's a good 5/8 antenna at 149.00 , shipped to your door.

that leaves you 51.00 for coax, and the rest.

you have $15.00 for one ten foot length of mast pipe, and less than 30.00 for Coax and hardware. Taxes are going to be a few dollars too. Mounted on the top of a single story roof peak, you are going to get out less than 2 miles with 5 watts. (Base of antenna at 25' above ground level.) You are real close to or just over $200.00

BUT, Take $10.00 and build a desert slim jim. http://geocities.com/juliusno1776/
Put it on top of 3 -10"lengths of tv mast pipe ($45.00), spend 30.00 on decent coax, RG-8/X or Times LMR-240 and hardware. Less than $90.00
You will double your range, just by wisely spending your resources.
(Base of antenna at 45' above ground level. )

You will note, you have money left over, almost what you need to upgrade from a Max Pro 1 to a Max Pro 3 . You just went from 5 to 7 watts to 15 !

You will also have a better understanding of how antennas work if you roll your own.
Thu Jan 20, 2005 8:23 pm View user's profile Send private message
aidanpete
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Post Reply with quote
do you tune this antenna the same way you tune the 5/8 antenna or is it set at the same frequency for good...
Mon Jan 24, 2005 6:28 pm View user's profile Send private message
pcs
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Post Reply with quote
They are both tunable.

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Marko - PCS Electronics
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Mon Jan 24, 2005 7:18 pm View user's profile Send private message Visit poster's website
Dr. No
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Post Reply with quote
aidanpete wrote:
do you tune this antenna the same way you tune the 5/8 antenna or is it set at the same frequency for good...


Pretty much for good. That is why you do an open frequency search first!

You could rewire it with out too much hassle.

The slim jim antennas are good for over one mhz either side of where they are cut for.

See: http://www.geocities.com/juliusno1776/measure.html

the main page: http://www.geocities.com/juliusno1776/
Mon Jan 24, 2005 7:49 pm View user's profile Send private message
pcs
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Post Reply with quote
Nope, Comet and 3/4 can both be tuned. It is very desirable
that you have SWR meter when you do this, though.

But a SWR meter is a good thing to have anyway so you need
to get one at some point anyway, if you're seriously into this
kind of stuff.

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Marko - PCS Electronics
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Mon Jan 24, 2005 7:54 pm View user's profile Send private message Visit poster's website
aidanpete
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Post Reply with quote
i'm hoping to have enough money soon for swr meter but thing about the comet is that you can change the frequency when ever you want is the 3/4 one just as easy. also why don't ye sell these famous j poles if there so good i'd certainly buy one as i don't have the technical know how to make one
Wed Jan 26, 2005 4:43 pm View user's profile Send private message
pcs
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Post Reply with quote
Well THE 3/4 IS basically a form of a J-pole,
it may even performa bit better.

3/4 is as easy to tune as Comet.

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Marko - PCS Electronics
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Wed Jan 26, 2005 5:18 pm View user's profile Send private message Visit poster's website
musicradio1075
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Post I Bought The 3/4 Wave Antenna - Love It! Reply with quote
I recently purchased the 3/4 wave antenna and installed it just over a week ago. I am totally satisfied with it. It performs just as it was described! I had been using the Comet 5/8 wave for about 3 years, and was happy with it's performance, but it got to where it wasn't performing correctly...my SWR was way out of sync. I was going to get another Comet, but happened to find the PCS website, and saw the 3/4 wave advertised. It sounded so good that I decided to order it, even though it was a little more money that I had intended to spend. Believe me, it was well worth the extra expense!! My signal penetration is so much better in my coverage area. My SWR is the best it's ever been...I had the antenna factory tuned to my frequency. Also, my Power Meter shows an additional 10% - 15% of output power from my transmitter....not sure how that's possible since I was operating right at the maximum power rating for the transmitter before. Bottom line, I highly recommend this antenna for anyone needing a new one. Plus, my dealings with PCS were great....they answer questions quickly, and the antenna was shipped within a couple of days of the order.
Wed Mar 16, 2005 11:24 pm View user's profile Send private message Visit poster's website
pcs
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Post Reply with quote
aidanpete wrote:
i'm hoping to have enough money soon for swr meter but thing about the comet is that you can change the frequency when ever you want is the 3/4 one just as easy. also why don't ye sell these famous j poles if there so good i'd certainly buy one as i don't have the technical know how to make one


This is better than the J-pole, my friend!

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Thu Mar 17, 2005 10:22 am View user's profile Send private message Visit poster's website
pcs
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Post Re: I Bought The 3/4 Wave Antenna - Love It! Reply with quote
musicradio1075 wrote:
I recently purchased the 3/4 wave antenna and installed it just over a week ago. I am totally satisfied with it. It performs just as it was described! I had been using the Comet 5/8 wave for about 3 years, and was happy with it's performance, but it got to where it wasn't performing correctly...my SWR was way out of sync. I was going to get another Comet, but happened to find the PCS website, and saw the 3/4 wave advertised. It sounded so good that I decided to order it, even though it was a little more money that I had intended to spend. Believe me, it was well worth the extra expense!! My signal penetration is so much better in my coverage area. My SWR is the best it's ever been...I had the antenna factory tuned to my frequency. Also, my Power Meter shows an additional 10% - 15% of output power from my transmitter....not sure how that's possible since I was operating right at the maximum power rating for the transmitter before. Bottom line, I highly recommend this antenna for anyone needing a new one. Plus, my dealings with PCS were great....they answer questions quickly, and the antenna was shipped within a couple of days of the order.


Sounds almost like a paid advertisement
Thanks for the tumbs up, have fun with this antenna!
By the way, there's a special for this antenna under Special deals.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Thu Mar 17, 2005 10:24 am View user's profile Send private message Visit poster's website
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