Amps: Direct Connect versus Repeater?

J.C. Roberts · EVDO Fledgling Joined: 14 Nov 2006 Posts: 14

Though I could probably make some very bad jokes about "Insertion Loss" I doubt everyone would find them funny, let alone appropriate. ;-)

Anyhow, I'm trying to do my homework on wired (Direct Connection) versus unwired (Repeater) amplifiers but I haven't found any good technical reading materials that offer comparisons?

Yes, Unwired/Repeater amps are more expensive than their Wired/Direct counter parts but that is not a huge issue for me. I'm more concerned with usability and signal quality?

Yes, you can use a Wired/Direct amp with a splitter to drive more than one wired device (EVDO Card, Cell Phone, etc.).
http://www.digitalantenna.com/cellcombine.html
(note: I searched their site but it seems Wilson does not make similar devices... -probably because they want to sell their more expensive Wireless/Repeater amps ;-)

And possibly Yes? -I think you can get away with using a Wireless/Repeater amp in a direct connection arrangement if you use a voltage isolator/block between the amps rebroadcast antenna port and the cellular device. Well actually, at least in theory you could run both wired/direct devices as well as a rebroadcast antenna on the power pass through port.
http://www.e-meca.com/rf-power-divider/power-divider-dc-block.php

If you know anything about wired versus unwired or have any links to comparisons, please drop kick me in the right direction.

J.C. Roberts · EVDO Fledgling Joined: 14 Nov 2006 Posts: 14

Hi Max,

RF is not merely an irony of coy and capricious, but when buying hardware, it's very easy to paint yourself into a corner.

Though I agree a Wired/Direct connection will most likely be superior, it is still possible to do with a Wireless/Repeater type amp. All you need to do is put a DC blocking terminal on the rebroadcast antenna line, and it's no longer fit to drive an antenna (i.e. it won't fry cellular card or phone hardware directly connected to it). You don't necessarily need a DC Blocking splitter (as previously linked) and you can use something as simple as this:
http://www.fxr.com/pdf/HR-21-22.pdf

For the price of 0.08dB insertion loss of that DC block, you can convert your wireless amp to a wired amp. I would guess it's actually a lot less loss than what occurs with the rebroadcast/output antenna of the amplifier to the cellular device.

If using a DC Blocking splitter like the Meca DC802-4-1.500V, you can have *both* a wired connection and a wireless rebroadcast/output antenna working off the same amplifier.

Since usibility/features are an important consideration when buying RF hardware, I'm kinda thinking going with a wireless/repeater amp would be my best bet since I can always just use a DC block to use it for a wired/direct connection?

Please correct me if I'm wrong.

J.C. Roberts · EVDO Fledgling Joined: 14 Nov 2006 Posts: 14

Gordon,

As you've already guessed, for me it's about the learning and engineering going into my "little" wireless project, not about the cost in time or effort. Wink

If it's not too much trouble for your RF engineer, I would love to know how exactly the output ports differ between the wired and wireless amps?

BTW, he nailed the date about perfect. I'm familiar with 10 year old tech, primarily for satellites where you'r sending 15 to 24 VDC down the coax to power the Rx/Tx LNB's on the dish.

Also, both DC Blocks and splitters of various sorts get lots of use with Spectrum Analyzers and high end oscilloscopes. The reasoning is to protect the expensive test equipment from potentially harmful voltages. In other words, passive signal inspection.

I've tried contacting you through the web form on your site (maxsignal.com) but it never seems to confirm that the message was sent? Since some of my questions involve stuff I shouldn't link to on this forum, please contact me through email. (jcroberts at designtools dot org).

n6gn

n6gn