George Hardesty

Jan 192016
 

Spatial diversity is a useful feature for overcoming multi-path interference. By providing spatial diversity, the radio’s internal circuitry can select between the two receive antennas for better wireless reception.

In the case of 802.11n or MIMO applications, two or more spatially or polarization diverse antennas are required for the radio to operate at its highest data rate.

 Posted by at 10:37 am Antennas, Antennas No Responses »
Jan 192016
 

Signals received at base station antennas are typically elliptically polarized in a way more like vertical polarization than horizontal polarization. This creates a common problem with dual polarized base station antennas (like the first generation of Ubiquiti dual-polarity antennas) since the vertically polarized antenna element generally maintains a stronger receive signal than the horizontally polarized antenna element.

This can be overcome by slanting the orthogonal polarized antenna elements to +/- 45 degrees. By slanting one of the antenna elements 45 degrees to the left and the other 45 degrees to the right, improved equality in received signal levels can be achieved.  This can help improve coverage in congested environments.

Another advantage to using these types of cross polarized antennas is in co-located wireless system installations. Since multiple antennas are used within the same facility or tower, this often creates interference issues among antennas which are usually vertically or horizontally polarized. Using 45 degree slanted cross polarized antennas on the client side as well on the base station side can greatly reduce interference and improve performance.

Ubiquiti’s AirFiber 5GHz Dish series uses 45-degree slant for improved noise immunity and Signal‑to‑Noise Ratio (SNR)

 

 Posted by at 10:35 am Antennas, Antennas No Responses »
Nov 292015
 

For all credit requests less than $15,000, the process is very simple.

  1. Request the one page Credit Application from Customer Service
  2. Complete the application.
  3. Email the form to Customer Service

Data Alliance Customer Service will be in touch with you shortly. You should expect an approval within 48 hours, depending on how quickly your references respond to our requests.

You can help speed the process along by calling your references and bank, alerting them that they will be receiving a trade reference request from Data Alliance and to please respond quickly.

Frequently Asked Questions

Q. What counts as a trade reference? A. Any trade credit account that has had activity in the past 12 months, whether it be an open account with supplier or even a Home Depot account.

Q. What if I don’t have a bank account? A. If you don’t have a current business banking relationship or bank account, any loan balance on a vehicle, equipment or building loan will work. Fill out the bank reference part of the form with the bank that holds your loan, including your loan reference number.

Q. What information do you ask my trade references? A. The only information we ask your trade references is to confirm the information you provided and whether or not your account is in good standing. That’s it.

Q. What bank information do you ask for? A. We will send your bank a form to verify that you are a customer in good standing. See the sample bank form later in this document. We won’t ask for any balances, types of accounts or anything specific.

Q. What does ‘good standing’ mean? A. It means that you are doing whatever it is that you agreed to do.

 Posted by at 10:59 pm Credit Terms No Responses »
Sep 122015
 

Summary of Terms and Conditions :

  • Customer must be a corporation or LLC with credit history (not a proprietorship. Partnerships will be considered).
  • Business customers that pass our credit evaluation qualify to begin with 30 day net terms.
  • Customers with a good payment track-record with us will have their terms increased to 60 and then 90 days to pay invoices.
  • Contact Customer Service for a credit application
  • Customers are required to pay their invoices within the term-limit that we set after approval, and adjust according to performance, with notification in writing, by email.
  • We can accommodate credit lines up to $200,000

Credit Requests Less Than $15,000: Details & FAQ

HELPING YOU BUILD YOUR BUSINESS

Establishing good credit is one of the most important things you can do to grow your business. Data Alliance understands how to partner with you to accomplish just that.

  • We grant easy credit to new or small businesses.  Just starting out? Small but growing? No problem. We’ll start you with a credit limit equal to 125% of your largest verifiable trade balance with any other outstanding creditor. No personal guaranty required, no extensive credit checking process that takes days and days to complete. All we need are 2 trade references and a bank reference – it’s just that simple.
  • We grow your credit line quickly if you pay on time:  Pay your invoices within terms, and we’ll automatically increase your credit limit to 25% more than your highest paid accounts receivable balance. And we’ll keep doing that automatically until your credit line reaches $20,000.  You don’t have to ask or make any special requests, just pay your bill on time and grow your credit automatically.
 Posted by at 5:02 pm Credit Terms No Responses »
May 142015
 

RF connectors’ gender is not as you would expect, due to these factors:

  • Gender of threaded connectors is referring to the pins inside–not the threads.
  • Reverse polarization (“RP”) complicates the determination of gender:  See details below about Reverse Polarization

Connectors with “RP” in the name are further complicated by the “reverse polarization” (RP):

  • The pins are female when they appear to be male, and vice versa.
  • If the documentation refers to the connector as “reverse ____”:
  • This is the same as RP-____ (e.g,  “reverse SMA” = RP-SMA)

strong>Details about Reverse Polarity (RP) / Reverse Gender Connectors and Adapters

  • Reverse Polarity/Reverse Gender connectors satisfy FCC Regulation 15 by switching dielectrics and pins/contacts between genders.
  • For example, a Reverse Gender Male consists of a male body, however, the dielectric and contact are female.
  • Basically, an RP female will look like a standard male, and an RP male will look like a standard female. Reverse Polarity connectors and adapters will not mate with standard coaxial connectors.  To attempt to do so will damage the connector.
  • All of our cables with RP-SMA female have a bulkhead (nut and washer).  They will will pass through an exterior wall covered in sheet metal and will seal out weather and survive extreme temperatures.

N-Connector:  The N type of connector is available in threaded and slip on versions and offers a bandwidth of upto 11 GHz. Such connectors are usually used with smaller cables such as RG-225. These connectors are used mainly with coaxial type of cables that are designed to provide distortion free signals. N type connectors are available in right angled models that facilitate their use at cramped locations in order to let the WiFi antennas remain vertical.

BNC and TNC:  BNC or Bayonet Neill-Concelman connector is a locking connector. These connectors twist and lock onto the mounting post unlike many other connectors that press or thread onto it. Such connectors are used in situations where quick disconnect capabilities are required. TNC or Threaded Neill-Concelman version uses threads instead of the locking mechanism.

MCX:  They are smaller in diameter by 30 percent when compared to SMA coaxial connectors. Such a size enables further miniaturization of the hardware of the WiFi network. They are designed to press fit into the post on the router. They are mainly used with antenna cabling of smaller diameters.

May 092015
 

The speed/throughput of an Ethernet Cable connection is better by a multiple of as much as 4X, if the RG45 connections have 50 Micron Gold Plating, as compared to standard metal contacts.

Gold is a much better conductor than any other common metal, and so the amount of signal loss is far less using gold, compared to cheaper metals.

Cheap keystone jacks and mass-produced cables and  often have no Gold Plating in the contacts. The efficiency of these network cables is as low as 20% of a similar cable with 50-micron gold plating (and otherwise constructed of the same materials).

All of Data Alliance’s ethernet cables pass the Fluke test, and are produced with the finest materials, including RJ45 Plugs with minimum of 50 Microns of Gold Plating.  Data Alliance provides CAT5e and CAT6 and CAT6a patch and crossover cables for all networking aplications in 9 colors.

Why 50-Micron Gold Plating is Important

  • Connectors maintain the signal connection between the cable and the RJ45 jack or port.
  • As time passes, the connectors are exposed to corrosive conditions such as moisture and humidity: This results in a loss of signal quality.
  • More corrosion = lower quality

Gold is:

  • Highly durable
  • Highly conductive
  • Non-corrosive

The thickness of the gold plating affects the lifespan of the connection

  • The thinnest plating is called “flash plating”
  • The amount of gold plating on connectors is measured in microns
  • 50 microns ensures a stable, high-speed connection, that will last for many years
May 032015
 

“Rebox” product is new, physically undamaged and complete product with full factory warranty, but which arrived at our warehouse in a damaged carton, and therefore does not meet Data Alliance’s quality standards to be sold as new. It has been repackaged in a generic carton and discounted.

Data Alliance’s part number will end with REBOX after the SKU, signifying a ReBox product.

Special Terms and Conditions:

Because Rebox product has been discounted, special terms and conditions apply:  Data Alliance cannot accept any return of a ReBox product unless it is Defective On Arrival (DOA). In that case, standard DOA return policies apply, however a replacement can only be made if another ReBox unit of the same part number is available. Data Alliance will not replace a ReBox product with a new product at the same discounted price.

Orderable quantity is restricted to inventory on hand.

Apr 092015
 

Optimization of the link involves trying different settings of channel sizes and power:

  1. Long links:  For links over 10 miles / 22km:  Smaller channel size  20MHz is almost certainly going to work best on a link of this distance.  You should try 20MHz and then compare to 40MHz to compare the throughput with each size.
  2. Short links can use a wider channel size: 40 to 80 MHz, to get more throughput (as long as there is not too much interference).  Experiment with the channel size and see which one gives you the most throughput.
  3. Power level:  Adjust the power to see if you get more throughput by adjusting up and down
Alignment:  Optimize the alignment by making very small changes right and left, up and down and watching the reaction of the throughput.
 Posted by at 10:46 am Mimosa Backhauls Tagged with:  No Responses »
Mar 152015
 

Seven-Mile Link in Arizona:  Actual throughput (MAC layer):  300-400Mbps:  From small town to tower in remote area:  April 2015

  • Using B5c with 34dBi dishes on both sides
  • A lot of interference from operator’s own APs on one towers (12 APs on remote tower, 4 on the small-town tower).
  • Using 20-40MHz DFS channels
  • Not using RFArmor
  • This is an actual, working link

12km Link Example:

  • Noise floor:  90.49dBm
  • 21km link from a building in the city, out to a suburban or rural location, with one hill or small mountain in the path, but this is not high enough to be in the frenzel zone.
  • To make this 21km link, customer will need B5c with 34dBi dual polarity dish (2FT) on each end.  B5 with its 25dBi antenna gain is not sufficient.
  • Throughput at MAC layer:  200Mbps.  For higher throughput, you would need RFArmor.

Mimosa Backhaul products

 Posted by at 6:08 pm Backhaul links, Mimosa Backhauls Tagged with:  No Responses »
Mar 142015
 
  • Spectrum Re-Use:  Mimosa’s precision GPS Sync, GLONASS & 4×4 MIMO enables 4x the throughput on the same channel(s) that you have been using, in co-location towers and sites.
  • 4 stream 256-QAM MIMO
  • Integrated link redundancy:  Load-balancing over two non-contiguous channels:  Auto-failover
  • Advanced DFS resilience
  • Integrated RF shielding
  • Lightning/ESD +IP67

Mimosa Backhaul products

 Posted by at 1:46 pm Backhaul links Tagged with:  No Responses »
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