Batboard

Well, another O.O. Band question... this time re: imbe signal..

Radio in question:
Astro Spectra
T04RKH9PW9AN
FlashCode 580001-001000-8

Successful in gettin into 440Mhz, ham. Can RX/TX no problemo in conventional mode, PL/CSQ

Now, when I activate ASTRO/IMBE MODE on freq. say 446Mhz (ham) There seems to be a "loss" in the ASTRO Signal when TX. It does not 'open' other radios-my xts on same freq/settings.
My xts does not decode the unit ID. The RX light does flash. When heard over conventional scanner, Ast Spectra does TX. ( i hear the signal.. bzzz)

However when I TX from my portable, the Astro Spectra does RX and Decode unit ID on that 446Mhz freq.

Seeing how these are really not spec'd for 440Mhz, Im assuming Im trying to stretch it beyond what it can do. Again this is only experienced below 450Mhz. Everything else appears to be ok.

Is this abnormal? Any ideas or Comments? Anyone experience the same? Was hopin to use the apco ham repeaters i saw for NJ
Thank you for your time.

John J.

The ASTRO Spectra 450 - 470 MHz radio will have a problem with crummy receiver performance below 450 MHz. The RX's front end has some laser tuned filters that have very sharp skirts, with a sharp knee just below 450 MHz.

However, the so-called "Low Power" (10 watt to 25 watt, adjustable) ASTRO Spectra mobile is rated to work fine in the 438 - 470 MHz band, in both TX and RX.

I don't know how the TX behaves in a 450 to 470 MHz ASTRO Spectra, but I certainly wouldn't rely on it to work properly below 450 MHz.

Larry

The R3 range Spectra only has tuning values from 450-486 or so.

Even though it does not have any 440 tuning values, it can operate down there so long as your 450 tuning is on the mark.

Just because you are able to receive the XTS IMBE doesn't mean the Spectra will transmit a good one. Verify your transmit deviation limit and deviation balance are set correctly. If not, the XTS will not decode the signal even though the digital signal may "sound" like a good IMBE signal over a conventional radio.

Bottom line, you should get a Range 2 radio (438-470 instead of 450-482).

But, John, according to your ASTRO Spectra's serial number, you have a BRAND NEW radio! Now that is worth $5,000, and that might be worth trying to save!

Larry

ASTROMODAT check PM

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Well thank you ! I figured I was probably pushing it.
Guess then I'll have to stick w/ my portable.

Thank You for all the assistance, much appreciated.

John J.

I've been successful getting a couple of Astro Spectra 450-482 units to work IMBE in the ham band. Seems the soft pots for deviation in digital mode do not work below 450 MHz. I've changed chip resistors on the vocoder board to get the proper devitaion and also the proper mod compensation (there are two chip resistors that need to be changed). Once that is done you can then realign the radio's deviation and mod comp.

George