Help Connecting 110W Spectra to Echolink

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VE3CYX
New User
Posts: 1
Joined: Sun Mar 23, 2008 7:15 am

Help Connecting 110W Spectra to Echolink

Post by VE3CYX »

Can anyone out there post step by step instructions on how to connect a high power Motorola Spectra to Echolink.

Thanks.
kc7gr
Posts: 1031
Joined: Wed Mar 13, 2002 4:00 pm
What radios do you own?: Motorola, Icom, Sunair (HF).

Re: Help Connecting 110W Spectra to Echolink

Post by kc7gr »

(scratching head) Maybe it's just me, but that seems like an awful lot of power for an Echolink radio.

You'll need an appropriate PC, and controller software. The good stuff, on the server side, is Linux or Unix-based. I don't know of any packages that are Windows-based, and I wouldn't even think of connecting a typical Windows machine as an Internet-connected server anyway, mainly out of security concerns.

As for connecting to the radio itself, that's not too hard. You've got all the audio connections you'll ever need on the front D-sub 25 connector (the middle one). However, you must NEVER short the speaker leads together or ground either one. Doing so will destroy the audio PA. Best to use a 1:1 audio isolation transformer on the receive side if you're going to tap the speaker output.

If you do end up using that Spectra in an Echolink configuration, I would recommend turning the output power down to between 55-75 watts. That will not only draw less current, and make less heat, but it will greatly increase the useful life of the final output devices.

Happy tweaking.
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Bruce Lane, KC7GR
"Raf tras spintern. Raf tras spoit."
SlimBob
Posts: 911
Joined: Thu Dec 18, 2003 11:38 am

Re: Help Connecting 110W Spectra to Echolink

Post by SlimBob »

I'll save you some grief when it comes to matching speaker level to mic level -- you're going to need to use a transformer of some form. Look into power resistors and/or light bulbs as audio loads for the PA.

I lucked into a few 20 ohm to 600 ohm transformers; YMMV.
Jim202
Posts: 3610
Joined: Sun Sep 09, 2001 4:00 pm

Re: Help Connecting 110W Spectra to Echolink

Post by Jim202 »

There should be a fixed audio output level pin on the db25 connector. You also might have to move the control
cable from the head over to the right side connector and use the db25 connector nearest the DC power cable
for the Echolink connection. Reason I say this is there is no PTT pin connection on the right connector unless you
add it. It is however available on the left connector near the DC power connector.

Jim


SlimBob wrote:I'll save you some grief when it comes to matching speaker level to mic level -- you're going to need to use a transformer of some form. Look into power resistors and/or light bulbs as audio loads for the PA.

I lucked into a few 20 ohm to 600 ohm transformers; YMMV.
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