MSF5000 Tuning down
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MSF5000 Tuning down
Have a MSF5000 CXB station that was on a 451/456 freq and I programmed it to a 443/448 pair and no matter how I turn the preselector slugs or the injector coils I can't see any receive level coming through when I look at position #2 on the metering panel. There is a dummy load on the TX and a unity mobile whip on the SMA connector on the preselector's input. When the station was on the 451/456 pair I saw relative rx strength on the metering panel when a HT keyed up a few feet away from the station. Is there any other specifics when trying to tune a MSF5000 down to the ham bands? I tuned the RX/TX VCO'S to 38 microns already so I have good lock. This is the 430-470 MHz version because I checked the model number.
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Andy Brinkley
- Batboard $upporter
- Posts: 377
- Joined: Mon Sep 03, 2001 4:00 pm
- What radios do you own?: FMR80D and a Motrac with Scan
Re: MSF5000 Tuning down
With the MSF-5000 you must follow the alignment instructions in the manual exactly as listed, including injecting the signal with a signal generator and the test cable as described in the manual, in order to get the readings listed on the test set.
Andy / NC4AB
Re: MSF5000 Tuning down
ok, well now i have a bigger problem, i have a signal in proximity that can bring up the transmitter but no audio comes through. i can key the machine but it just makes the transmitter key up no audio no static burst nothing
Re: MSF5000 Tuning down
Did verify that the repeater was working correctly on its original frequencies before you started?
Re: MSF5000 Tuning down
My two bits worth:
You can take Andy's remarks to the bank.
The reason for the "weird" alignment procedure is that the MSF was designed to be a multi channel station, that is why the receiver front end as well as the duplex filter is designed to meet the F1-F2 spec. It is a window.
Some notes:
Be very careful to properly terminate the antenna jack, follow the instructions exactly.
It is permissible to peak L6 on the receiver for best receive. The important thing is to have no desense.
RX M3 is the injection level to the mixer board, must be about half scale. The injection filter can grow whiskers, which will make tuning erratic or impossible. This has been discussed at length.
The transmit filters may present a problem.
The manual calls for a Boonton Milivolt meter with the 50Z adapter, a common item in Motorola shops of the day.
I use the tracking generator function in my Motorola R2600B, another possibility is an RF demod probe, a meter or sweep generator function of an R2001 or similar.
Keep in mind that this is a 55W station.
Your failure of repeat audio may be due to incorrect receive or audio qualifiers.
Look at the archive of a known good station, or select conv.def archive file from your RSS root directory.
Another possibility is to construct a new code plug from scratch. This is the purpose of the .def files.
Certain specific station types, such as trunking have unique .def files.
Be sure to delete the secure feature under the options screen.
It should only be necessary to enter the frequencies, PL code, station ID if required, you should have a functioning repeater.
You can take Andy's remarks to the bank.
The reason for the "weird" alignment procedure is that the MSF was designed to be a multi channel station, that is why the receiver front end as well as the duplex filter is designed to meet the F1-F2 spec. It is a window.
Some notes:
Be very careful to properly terminate the antenna jack, follow the instructions exactly.
It is permissible to peak L6 on the receiver for best receive. The important thing is to have no desense.
RX M3 is the injection level to the mixer board, must be about half scale. The injection filter can grow whiskers, which will make tuning erratic or impossible. This has been discussed at length.
The transmit filters may present a problem.
The manual calls for a Boonton Milivolt meter with the 50Z adapter, a common item in Motorola shops of the day.
I use the tracking generator function in my Motorola R2600B, another possibility is an RF demod probe, a meter or sweep generator function of an R2001 or similar.
Keep in mind that this is a 55W station.
Your failure of repeat audio may be due to incorrect receive or audio qualifiers.
Look at the archive of a known good station, or select conv.def archive file from your RSS root directory.
Another possibility is to construct a new code plug from scratch. This is the purpose of the .def files.
Certain specific station types, such as trunking have unique .def files.
Be sure to delete the secure feature under the options screen.
It should only be necessary to enter the frequencies, PL code, station ID if required, you should have a functioning repeater.
Aloha, Bernie
Re: MSF5000 Tuning down
actually i cleared the no audio pass by leaving the idle TX calculation on Auto not manual and so the idle tx freq is parked on the same TX freq. Yes I did finally get the coils to get the signal to squeak pass them but it was tough. I was initially turning the coils way to fast right past the RX window in question. So far all is well now. Thanks for all the input guys.