Users may not create topics, posts, or private messages containing or relating to the following material (especially pertaining to Motorola copyrighted software, unless you want Motorola to come along and shut this site down):

  • Listing for sale or trade of, or links to sites offering for sale or trade of, or giving away, Radio
    Service Software (RSS) or Customer Programming Software (CPS)
  • Profanity, pornography, defamation, or slanderous remarks directed towards any individual or entity
  • Commercial advertising (except in the Batboard Vendors forum, as approved by the Admin/Mod Staff)
  • Any other items which may be deemed as offensive

If any topics, posts, or private messages containing or relating to the aforementioned material are brought to the attention of the Admin/Mod Staff, they will be deleted.

Additional FAQ items appear here in Forum Rules. Please review them for posting guidelines and further clarification.

Quantar SINAD and pre-selector alignment

This forum is for discussions regarding System Infrastructure and Related Equipment. This includes but is not limited to repeaters, base stations, consoles, voters, Voice over IP, system design and implementation, and other related topics.

Moderator: Queue Moderator

chrismec
New User
Posts: 4
Joined: Fri Apr 20, 2018 5:33 pm

Quantar SINAD and pre-selector alignment

Postby chrismec » Wed Aug 08, 2018 7:30 am

Hi all, been diving into Quantar's lately and been noticing on the two UHF radios we have that the SINAD will not get near 12dB when the radio is at full volume, even at power levels as high as -80dB. BUT, if I drop the volume down one notch the distortion level drops and I can get the 12dB at around -110dB. Being new to quantar's I performed the pre-selector alignment but this only seemed to make it worse. I tried with the calculated freq values as noted in the procedure first, then the actual frequency, same result. In the end I just adjusted the pre-selector by ear. Do any of you all have any insight you would care to share? Thank you!

User avatar
kb4mdz
Posts: 275
Joined: Tue Oct 02, 2001 4:00 pm
What radios do you own?: Too many for the time I have.

Re: Quantar SINAD and pre-selector alignment

Postby kb4mdz » Thu Aug 09, 2018 1:07 pm

Just off the top of my head, I don't know that SINAD is defined at full volume; I'll look into it.

But that makes sense; every time I've run a SINAD test, I just set to volume control to a 'comfortable' level, maybe mid-range. And I'm not surprised by your results either, as audio chains in such simple radios as LMR (as opposed to your stereo) would distort at the maximum volume.

Remember, SINAD is Signal+Noise+Distortion, over Noise + Distortion. Bump up the volume control to max, you'll be introducing distortion other than that which is inherent to the audio chain, making your SINAD value useless.

What's your final RX level, in dBm or uV?

User avatar
MotoFAN
Posts: 1025
Joined: Thu Jun 28, 2007 6:46 am
What radios do you own?: Approx. 50: Moto & Kenwood

Re: Quantar SINAD and pre-selector alignment

Postby MotoFAN » Thu Aug 09, 2018 1:28 pm

Check papers for proper volume level. Most of SM describe that voltage Vrms you must set before measure SINAD, for e.g. 5 Volts peak to peak @ 8 Ohm load.

Also, you must have some adapter to measure SINAD - 2 caps and load (speaker emulation). The same scheme is published in many service manuals, including Motorola and Kenwood. Do you have it or just connected service monitor instead of speaker? If YES, it's wrong!

Also, -110 dBm @ SINAD 12 dB definitely is not nominal sensitivity. You must get something like -118 as minimum. But -119..120 is nominal.

Anyway, read Quantar manual and RSS help to ensure that you're precisely following the procedure.
I am biggest fan of XTS2500 and ASTRO Digital Saber.

chrismec
New User
Posts: 4
Joined: Fri Apr 20, 2018 5:33 pm

Re: Quantar SINAD and pre-selector alignment

Postby chrismec » Wed Aug 15, 2018 8:23 am

The adapter I am using to measure is a Motorola 3082059x01 (Amp 558461-1) and an Aeroflex 3550. The moto procedure states to set the volume to full. In the end, after the pre-selector alignments by ear alone on two UHF radios, 12dB sinad came in at -113dB on one radio and -122 on another. The second radio only came in after restoring air conditioning to the building! Before that its best was also -113.


Return to “Base Stations, Repeaters, General Infrastructure”

Who is online

Users browsing this forum: No registered users and 1 guest