We have been receiving many questions from customers and other people about the 5/8 Co-linear Mamasita ver 4 Way Stacked Dipole.

The 4 way stacked dipole, if the dipole spacing is optimum, will have a gain of about 8.5dBi. The Mamasita is 7.8dBi, so it’s just about -0.7dB lower than the 4 dipoles. Now 0.7dB is virtually nothing, almost insignificant. But there’s also a couple of other things that should be noted when comparing Mamasita ver 4 way stacked dipole.



Gain 7.8dBi
Mounts to the top of the tower
True omni-directional
Requires no more than 0.5m (1.5Ft) at the top of the tower.
Center point of radiation 6.5m (21Ft) higher than 4 Way Stacked dipole.

4 Way Stacked Dipole

0.9 Wavelength (about 2.7m) Dipole Spacing Gain 8.5dBi
Mounts to the side of the tower
Not true omni-directional, the tower creates a small shadow to the signal
Requires 9.5m (31Ft) of tower space
Center point of radiation 6.5m (21Ft) lower than Mamasita

On optimized spaced 4 way stacked dipole needs 31 feet of tower space in length, in the middle of that length, halfway up or down at 15.5 feet, this is the maximum radiation point. Therefore at best the maximum radiation point is 15.5 feet below the top of the tower. Now given that Mamasita sits on top of the tower and the maximum radiation point is again halfway up the Mamasita, then the maximum radiation point of Mamasita is about 6 feet above the top of the tower. The difference between -15.5 and +6 is 21 feet. To conclude, Mamasita has at least a 21.5 feet height advantage over the 4 way stacked dipole. In terms of range or distance covered, this height advantage completely and by a large margin outweighs the small gain advantage of 0.7dB of the 4 way stacked dipole. Therefore Mamasita clearly is the winner in this regard.

The Mamasita prototype is going to Africa in next few days. A customer is going to install it, use and basically test it, not really for gain, as we know that’s good, but really for durability in diverse weather and climate conditions. We will give it 3 months of testing, if it’s all good, then we will go into full production and marketing of Mamasita.

Paul Hollings.

Customers like to send their old transmitters back to us for repair, but when you add up the shipping costs, this often costs more than just buying the new parts needed.

You can the buy the complete 100W block set from us as shown in the picture. This is completely assembled and tested and ready to drop in side your old power amplifier case, but make sure your power supplies are still good and reliable with the correct voltages. These 100W block sets are taken out of a fully operational brand new 100W transmitter, so all the screws and holes are in the correct places and then you have no hassle fitting the units when they are delivered to you.

If you need any further information don’t hesitate to contact us

1. Accessing your Router to Configure the Barix internet STL

Before starting this process you must know how to access your router and have the username and password. If you don’t, check out your documentation, your router’s label, your manufacturer’s website and possibly your internet service provider for this. Without this information you cannot set up the internet STL and should not proceed any further.

2. Get the Instreamer IP Address

You will need some headphones with a the standard small 3.5 mm stereo plug, like phone and MP3 player headphones, nothing expensive. Now get a pen and paper. Connect the Instreamer to the router using a short network cable with RJ45 connectors. Plug the headphones into the Instreamer and put them on your ears. Power up the Instreamer and within a few seconds you will here some numbers spoken to you through the headphones. Write these down using your pen and paper. The numbers will normally be 192.168. X . X or 10.0. X. X where X will be some number between 0 and 255. These numbers are the Instreamer IP address and you will need them for the Internet STL configuration.

3. Make the Instreamer IP Address static

Go to any computer that is using the internet connection on the router. Open a browser and type into address bar the Instreamer IP address you wrote down. In our example it was, your number will almost certainly be different. You should see the Instreamer configuration screen shown at the top of this page.

Click CONFIGURATION on the top menu, then click Advanced Settings, then Network on the left side menu. You should see the following screen. In the IP Address field enter the Instreamer IP address. Click Apply just below the left side menu. The Instreamer will save the new settings and make a four second reboot.

Instreamer Configuration with a Router for an STL 2

4. LAN Local Area Networks and WAN Wide Area Networks

The Instreamer IP Address is a local area network address or LAN IP address and is only available to other computers and devices connected to your router. Your Instreamer needs to be visible to the world Wide Area Network or WAN for the internet STL to work correctly

Instreamer Configuration with a Router for an STL 3

Your router has WAN IP address. This is assigned by your internet service provider. To find the number you have been assigned go to ipaddress.com or whatismyip.com

In our example our router WAN IP address is The router needs to be configured so that when you type the WAN IP address into the browser address bar anywhere in the world, you see the Instreamer screen just the same as if you type in the Instreamer LAN IP address. To do this we need to connect together the router WAN IP address and the Instreamer LAN IP address by forwarding port 80 in the router configuration.

5. Configuring Router Port Forwarding

Each manufacturer uses different software on their routers. There are some screenshots below of the port forwarding settings from each of the major brands. If your router is not shown here, it should still give you an idea. For port forwarding you need to look in the menu sections Ports, Port Forwarding, Firewall or Virtual Servers. There are five fields to fill in, these fields are known by slightly different names on each router, but they are essentially the same thing. Complete the five fields as follows:

  • Name/Application/Description: INSTREAMER
  • External/Start/Inbound Port: 80
  • Internal/End/Local Port: 80
  • Protocol/Traffic Type/Type: BOTH/ANY
  • IP Address: Instreamer IP Address you wrote down

When you have done this, save the changes in the router and then restart the router and log in again and make sure the settings have been saved properly.


Instreamer Configuration with a Router for an STL 4


Instreamer Configuration with a Router for an STL 5


Instreamer Configuration with a Router for an STL 6


Instreamer Configuration with a Router for an STL 7

Now enter WAN IP address that you found at ipaddress.com or whatismyip.com into your web browser. If it’s working correctly you should see the Instreamer configuration screen just the same as if you type in the Instreamer LAN IP address.

To be absolutely sure it’s working go to the following site and use their tool http://www.yougetsignal.com/tools/open-ports/ In our example it displayed the following screen.

Instreamer Configuration with a Router for an STL 8

You should now be able to access the Instreamer from anywhere in the world using the WAN IP Address.

Best Antenna For FM

We think so simply because it delivers more gain, it’s physically stronger and it’s bigger than any other single based FM antenna that is available on the market for FM broadcasting. It also looks more elegant than the equivalent four dipoles on the side of a tower. Keep reading and looking at the photos and I’ll tell you more.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 1

Elvis and Alex

These two guys are Elvis and Alex who are employees of Aareff and have been working on this antenna now for around 3 to 4 months. When we first started this project I said we need to make the best antenna and the most powerful in a single unit that there is for FM broadcasting.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 2

Arriving On Site

We arrived on site in a small field about 1/4 mile from our industrial complex in Pisano, Santiago, Dominican Republic. The guys start to put the antenna together. Fitting the antenna to a mast or pole is easy on only requires a 13mm spanner to tighten up the two U Bolts.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 3

Clamping The Antenna To The Pole

In this close up photo you can see the base section with the two U bolts and how easily it clamps to the pole or mast. It’s easy to do this on the ground, but it’s also possible without too much trouble to clamp it in place if the pole is already on a roof or tower. The part you see with the yellow and blue rubber bands is the impedance matching inductor, the small round tube slides up and down between the bars to tune the antenna. this is only temporary for these field tests, the finished model will not have this.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 4

The DIN 7/16 RF Connector

Finger tightening the 13mm nuts up. You can see the the RF connector, it has a blue cover over it to protect it from damage. This is high powered 7/16 DIN connector that is silver plated and uses a Teflon / PTFE. If the connector is clean, in good condition and the coaxial cable is fitted properly, then power handling can be up to 3KW.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 5

Antenna Cable Loss

Final tighten on the 13mm nuts of the two U bolts and fitting the coaxial cable to the 7/16 DIN connector. We are using 20m of LMR400 to make the tests, this cable at 100MHz has a loss of close to 1.8dB, therefore the antenna cable will improve the measured return loss by double at a figure of 3.6dB or an VSWR of 0.2. This means that an VSWRof 1.3 measured at the end of the 20m cable is really an VSWR of 1.5 at the RF connector of the antenna.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 6

3/8 Wave Phasing Stub

The antenna is now vertical and looks amazing against the Caribbean blue sky. In this photo you there is a crystal clear view of the 3/8 wave phasing or delay stub. If your not familiar with radio terms, this is the coiled thing half way up the antenna on the white tube. Without this phasing stub the antenna will not radiate efficiently or give a gain of +7.8dBi to the horizon. I’m going to discuss in more detail in a later publication how exactly this works.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 8

Teflon/PTFE insulator

Another beautiful picture against the back drop of the Dominican sky. The white tube half way up the antenna is a Teflon / PTFE insulator. This material has excellent dielectric properties, there so good that the radio signal thinks the insulator is virtually invisible, not even there, just like air. Given this it can handle massive RF voltages without any heating effects.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 9

Panoramic View

A panoramic view in this picture. At four metres in length, this is a big performance antenna for FM broadcasting and is equivalent in terms of gain to four half wave dipoles mounted on the side of a tower that use at least ten metres of space. Looking up at the dipoles from ground, to the viewer they look ugly. Our 5/8 co-linear single straight vertical is elegant to look at and not too obtrusive, but has the same performance as the four ugly dipoles. Unless you have some unusual reason to use dipoles the 5/8 co-linear is the best antenna to use.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 10

Impedance Match

This picture shows a clear view of the base of the antenna. The 7/16 DIN connector is fitted, but it can be fitted with the smaller N type or SO-239/UHF Teflon / PTFE type if requested, but these smaller connectors will limit the power handling to about 1KW. The two inductor bars can be seen seen clearly, these form an RF transformer to match the 50 ohm input impedance to roughly 1000 ohms at the bottom of the main radiator.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 11

Design Strength

Another amazing view of the entire length of the antenna against the blue sky. This is the best antenna to use for FM due to the phasing stub that you see halfway up being physically very strong. It is made of solid 1/2 aluminium round bar. Believe we had to make several before we go the hang of bending correctly. The phasing stub is really rigid and screwed really tight to the white Teflon / PTFE insulator. If you’re wondering, it won’t distort or change in heavy winds. Not only is it the best antenna for FM, it is the strongest single antenna available.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 13


The final full length picture, again a nice clear view from another angle of four main sections of the antenna, 1. the base, 2. the bottom 5/8 radiator, 3. the Teflon / PTFE insulator and phasing stub and 4. the top 5/8 radiator. The bandwidth of this antenna is really good for a non broadband type antenna. This particular sample was made for 89.0 MHz, the bandwidth was tested to be +/- 3.5 MHz to the 1.3:1 VSWR points, in the middle at 89.0 MHZ it was 1.0. That’s a total bandwidth span of 7 MHz which is 1/3 of the entire 88 to 108 MHz band. With just three models we can cover the entire band.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 14

Field Tests

This is Alex my son who works at the office between university classes studying Electronics. To prove this is the best antenna for FM available he is measuring the near field low angle field strength. It’s exactly as expected. At 2m from the antenna just below the ground plane rods we are seeing about -6dB (quarter power points) relative to the main lobe at 0dB and azimuth of 0 degrees. Right under the antenna ground rods next the mounting pole the field strength is zero, there’s no trace of RF. This is good and indicates that the phasing stub half way is working correctly, if not there would be “End Fire” out of the top into the sky and also out of the bottom into the ground. Later, not shown in the photos, we tested the antenna at 100m away using more power and confirmed that the main lobe was indeed at 0 degrees azimuth. We expected a little tilting upwards, maybe a couple of degrees, this is normal for 5/8, but no, it was solid at 0 deg with maximum radiation to the horizon. The field strength was double that of a single dipole, this is +6dB over a dipole or 4 times the power increase. This was sufficient evidence to verify our quoted figure of 7.8dBi was very close to correct and the antenna was working exactly as planned and designed.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 18

Solid Design

This is me Paul Hollings just demonstrating that I also like to get my hands dirty, this thing is heavy, the weight loading on the base section and the two U Bolts is enormous, but throughout all these tests the base section has remained sturdy, no buckling or distortion of the aluminium. It’s very strong because it’s also supported by a 2 inch diameter piece of Teflon / PTFE round insulator. Nothing in the base section moves, it’s solid.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 15

Successful Tests

Finally the tests are over and we lower it back to ground ready to return to our workshops and offices that you can see in the distance behind the trailers. It’s been an highly successful day and the results are everything we expected and more. This antenna without a doubt is the best antenna for FM broadcasting on the market, it’s the most powerful in terms of gain single antenna available.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 16

Thank You For Reading

Thank you for your interest in Aareff products and in particular looking and reading through this entire series of pictures. If you have any questions or comments, please enter them into this blog below.

Best Antenna For FM, +7.8dBi Co-Linear 5/8 Wave 17

By Paul Hollings

We are testing ‘Mamasita’ our new high gain (+7.8dBi) 5/8 co-linear FM Antenna. With 20m of LMR400 it will multiply your transmitter power by 5 times !!!, so with a 200W TX or amp it will radiate 1000W ERP.

I get all the best jobs, I’m the one opening the door. “Careful chaps, it’s taken us three months to get this FM antenna to this stage”

Our high gain (+7.8dBi) 5/8 co-linear FM Antenna

The two main tubes you see the guys holding are aluminium 1 and 1/2 inch in diameter with thick walls, you can see it’s rigid with no sagging even with the weight of the PTFE insulator in the middle.

Beautiful view of the new 5/8 co-linear fm antenna being taken from the R and D offices for tests

The design of this FM antenna is strong. The darker coloured tube on the right side of the photo is heavy steel and the bracket on the small square piece is supporting it without any problem.

The strong and rigid 5/8 co-linear fm antenna from Aareff

A nice view of the phasing stub on the far left hand side wrapped around the PTFE insulator. This has now been changed on the next revision, same shape and size, but made of solid aluminium round bar of 1/2 inch diameter. We’ll have pictures of this soon.

A clear view of the bottom 5/8 section of the co-linear from Aareff

This is Elvis (in blue t shirt) and I having a proud moment and looking forward to testing.

Elvis and Paul Hollings proud of the new FM antenna from Aareff

Preparing for field testing in an open field right next to our industrial park. It’s just over 30C on the 20th January, beautiful weather. We were trying hard to hold the FM antenna straight and vertical while keeping the ground planes sticking out by the base just over the tailgate of the car. If the tailgate goes above the ground planes then we start to distort the radiation pattern and see reflected power.

Two beautiful views of the 5/8 co-linear FM antenna in Santiago, Dominican Republic

You can see a nice view of the tuning bar sticking out of the square piece at the bottom. This is simply a half turn coil or inductor. The tube slides between the two flat bars. At the moment while testing it is held only with two elastic bands, when we have found the correct position, later we’ll drill holes in the bar and secure it in place with a long M6 stainless steel nut and bolt. Also a nice view of the four ground planes. Elvis is moving the bar whilst looking at the SWR meter in the back of the car.

Technician Elvis of Aareff adjusting the tuning bar on the 5/8 co-linear

You can see how big this thing really is, Elvis in the photo is about 5 11. On the right hand side picture below, you can see that we have changed the flimsy phasing stub half up the antenna for a strong solid 1/2 inch aluminium round bar formed and bent in to a stub. We are seeing a perfect 1.0 SWR with a bandwidth of +/-3 MHz to the SWR points of 1.5.

5/8 fm co-linear antenna, a clear view of the 7-16 RF connector and base matching section

Preparing to do some preliminary radiation pattern tests, these are not going to be perfect due to ground being so close, but they will give us an good idea if the main two radiator sections are phased correctly and if we’ve made the phasing stub in the middle correctly.

Testing the Aareff 5/8 co-linear antenna

We are now transmitting just a few milliwatts and I am checking to see if this signal can be received at the end of the antenna, if we see ‘End Fire’ signal here we’ve made a serious mistake with our calculations or construction. So far all’s good, not a single trace of ‘End Fire’ which basically means each of the two main radiators are within the 5/8 of wave limit and the phasing stub in the centre is pretty close to correct.

Checking for End Fire on the Aareff 5/8 co-linear FM antenna

In the left picture below I am measuring the maximum signal, it’s a little strange as it’s about 15 degrees down on the horizontal. Not quite sure why that is at the moment, I’m guessing the phasing stub is a little off or it’s an effect of the ground, we’ll know soon. In the right picture below I am confirming the antenna is radiating correctly, virtually no signal received again at this antenna end point.

Checking for End Fire on the Aareff 5/8 co-linear FM antenna

In the left picture below I am starting to see a little signal at this position, the meter is showing about a 30% of the maximum reading. In the right picture below I am seeing 85% of maximum signal.

Checking the main radiation lobe on the Aareff 5/8 co-linear FM antenna

Here again in the picture below at just 15 degrees below the horizontal we are seeing maximum 100% meter reading. A 15 degree tilt down is a bit of a surprise, not a problem we can’t resolve, but certainly a surprise. Normally with this type of FM antenna we are seeing tilting going upwards when the dimensions are not correct.

Checking the radiation around the phasing stub on the Aareff 5/8 co-linear FM antenna

By Paul Hollings