XTS5000 KFDshield

[saberthree]

TXPO is power out, you say you are having hard time decoding on RX. This really makes me think the REF osc is the culprit. Analog is much more forgiving than P25 as far as frequency error. Start there and then move on to TXPO and the deviation limit/balance to adjust the vocoder, although I do not really see any reason those could not be done with the antenna and the service monitor picking up the radio sitting on the desk via its antenna.

As old as these radios are, and the weird hardware you need, I suspect the last time it was aligned was at Motorola prior to being sent to the customer.

We have realigned a ton of ref oscs on XTS5000s which use similar RF chains and it makes a WORLD of difference on both RX and TX.

Yeah, I'm hoping I can get it done with a service monitor as an alternative until I can get a jig, it's certainly better than nothing! Maybe I can rig up some kind of connector to connect to the antenna port. Really though, I just need to learn how to tune and align my own radios, it's something I should learn anyway if I want to keep these radios in service for as long as I possibly could.

 

[wgbecks]

Yeah, I'm hoping I can get it done with a service monitor as an alternative until I can get a jig,

The Motorola RLN4460x Portable Test Box (jig) is not specifically a requirement to perform an alignment unless you have a need to inject
microphone audio or to gain access to speaker audio as is needed to perform SINAD measurements.

One can perform complete and accurate alignments using the ASTRO 25 Tuner program with nothing more than a standard service monitor in good calibration along with the correct RF adapter/cable to connect it to the radio's antenna port.

The Basic Service Manual (BSM) for your specific radio model combined with the "Help" section of the Tuner program provide all the necessary references needed to perform a successful alignment. One of the most critical alignment points is the "Reference Frequency" calibration that impacts both receiver and transmitter performance as has already been suggested by other respondents.

Additionally, some radio models (Frequency Band Dependent) require a "Front End" alignment to calibrate the receiver’s preselector across its operational frequency range while all ASTRO 25 radios are subject to Tx Deviation Balance and Tx Deviation Limit alignments that sets the
overall FM deviation, but more importantly, tune the P25 Modulation Fidelity.

 

[saberthree]

The Motorola RLN4460x Portable Test Box (jig) is not specifically a requirement to perform an alignment unless you have a need to inject
microphone audio or to gain access to speaker audio as is needed to perform SINAD measurements.

One can perform complete and accurate alignments using the ASTRO 25 Tuner program with nothing more than a standard service monitor in good calibration along with the correct RF adapter/cable to connect it to the radio's antenna port.

The Basic Service Manual (BSM) for your specific radio model combined with the "Help" section of the Tuner program provide all the necessary references needed to perform a successful alignment. One of the most critical alignment points is the "Reference Frequency" calibration that impacts both receiver and transmitter performance as has already been suggested by other respondents.

Additionally, some radio models (Frequency Band Dependent) require a "Front End" alignment to calibrate the receiver’s preselector across its operational frequency range while all ASTRO 25 radios are subject to Tx Deviation Balance and Tx Deviation Limit alignments that sets the
overall FM deviation, but more importantly, tune the P25 Modulation Fidelity.

Thank you for the response,
The real issue is for the XTS4000, the RF cable is supposed to go in the back of the radio where the battery is covering it, that's why I need a jig. The RF connector where the antenna goes isn't standard. Most motorla radios have that tiny pin in the middle of the antenna, this one is a bit different. The RF energy is being moved through the threads instead if that tiny pin on the antenna. I might be able to rig something up but indent know how accurate it would be.

 

[wgbecks]

Thank you for the response,
The real issue is for the XTS4000, the RF cable is supposed to go in the back of the radio where the battery is covering it, that's why I need a jig. The RF connector where the antenna goes isn't standard. Most motorla radios have that tiny pin in the middle of the antenna, this one is a bit different. The RF energy is being moved through the threads instead if that tiny pin on the antenna. I might be able to rig something up but indent know how accurate it would be.

Regardless of the XTS4000's need for the special RF test cable and test jig, as a minimum, I would recommend running Tuner to
perform the Reference Oscillator alignment "Off-Air" as means to verify and correct frequency errors. In actuality, this same methodology
can be used to calibrate the Tx Deviation Balance and Tx Deviation Limit alignments as well. Just skip the RF power characterization
and output alignments.

Granted, off air (physical) coupling between the signal generator and the receiver (rubber duck) is far from ideal, this method could still
be used to align the receiver preselector where the object is to tune each softpot for a peak signal level on each the respective test
frequencies.

 

[saberthree]

Regardless of the XTS4000's need for the special RF test cable and test jig, as a minimum, I would recommend running Tuner to
perform the Reference Oscillator alignment "Off-Air" as means to verify and correct frequency errors. In actuality, this same methodology
can be used to calibrate the Tx Deviation Balance and Tx Deviation Limit alignments as well. Just skip the RF power characterization
and output alignments.

Granted, off air (physical) coupling between the signal generator and the receiver (rubber duck) is far from ideal, this method could still
be used to align the receiver preselector where the object is to tune each softpot for a peak signal level on each the respective test
frequencies.

I'll have to ask the local radio shop if they can pull it off and be creative. They were a bit flabbergasted when I mentioned the 4000, they didn't even know that radio existed!!!