MSF 5000

[radioguruphil]

I just scored an MSF 5000 C24CXB, This is has a 6 watt PA. This was used as a reciever in a secure Astrotac voting system. I guess thats why it only had a 6 watt PA. This radio appears to be all set up for a 110 watt pa, which I have two off. Same power supply and all.

Now comes a couple of questions
This repeater is on 471 tx 474 rx Will it work on 464 tx 469 rx ?
Is the com spec narrow conversion kit a viable retrofit option ?
IT does have the secure option board installed. If I can retrofit this radio with the com spec kit what radios have the proper type secure and are also narrow band capable ?

That is all. Thanks in advance.

[d119]

I just scored an MSF 5000 C24CXB, This is has a 6 watt PA. This was used as a reciever in a secure Astrotac voting system. I guess thats why it only had a 6 watt PA. This radio appears to be all set up for a 110 watt pa, which I have two off. Same power supply and all.

Now comes a couple of questions
This repeater is on 471 tx 474 rx Will it work on 464 tx 469 rx ?
Is the com spec narrow conversion kit a viable retrofit option ?
IT does have the secure option board installed. If I can retrofit this radio with the com spec kit what radios have the proper type secure and are also narrow band capable ?

That is all. Thanks in advance.

Answer 1: The split on these radios is 435-475, so you just made it. It should do 464/469 just fine.

Answer 2: Yes, the Com-Spec narrowband kit is a viable retrofit option, and I recommend it.

Answer 3: No. Narrowbanding effectively kills all 12kbps SECURENET analog operations. You will not be able to use secure in the narrowband mode due to the fact that SECURENET requires more bandwidth than is available in narrowband operation. You might as well pull the encryption board out of it if you convert it to narrowband (which you'll have to by Jan 1, 2013).

[radioguruphil]

Thank you for your quick reply. Now we can ge to work and replace the two Midland radios that we cobbled together with a repeater maker. Thanks again.

[MassFD]

I heard that the FCC does not consider a wideband radio that had had modifications made to narrowband it a narrowband init unless it has gone thru the type acceptance procedure and issued a number by the FCC. I also no longer see filters on Com-Spec web site

[kcbooboo]

MassFD said

I also no longer see filters on Com-Spec web site

Perhaps that's because they're called "Narrow-band Kits"; they're mentioned on their home page. Access info here:

http://www.com-spec.com/narrow.htm

Bob M.

[xmo]

These issues have been specifically addressed by the FCC.

You CANNOT convert a wideband radio such as an MSF5000 to narrowband by putting in one of these kits and turning down the deviation! It might function but it is NOT legal:


http://fjallfoss.fcc.gov/kdb/GetAttachm ... l?id=32931

Question 1:
If a licensee uses a narrowbanding modification kit from a third-party manufacturer, do the kits need to be type accepted by the FCC? The referenced article above describes the modification kits: We have a lot of GE MASTR II repeaters and voted receivers, which aren’t narrowband capable. Communications Specialists, a company in California, makes numerous modification kits for various makes and models of base radios. The kit for the MASTR IIs includes new crystal filters and a capacitor, which converts it to narrowband. In bench tests before and after the modification installation, we gained 1 to 1.5 dB of quieting on the SINAD.
Answer: Based on this description, the kits would not need FCC approval because they consist of a set of passive components. However, using these kits to modify the radio entails a hardware modification in the operator’s repair shop, which requires a new equipment certification and a new FCC ID (See 2.1043(a)).

Question 2:
Can a licensee, using commercial, off-the-shelf test equipment bring a transmitter into acceptable limits of the emission mask for 11K2F3E by realigning the deviation from the current 5 kilohertz down to the new 2.5 kilohertz? For example, a licensee has new, narrowband-capable radios that he has switched to narrowband to use as a reference. After realigning a transmitter to produce only a 2.5-kilohertz deviation, the spectrum and modulation signals looked the same on his test equipment. As long as the licensees are transmitting within the new specs, will they be in compliance?
Answer: No. To be compliant with the commission’s rules, the radio must be specifically certificated for narrowband use under Part 90.

[MassFD]

We did the 2.5-kilohertz deviation thing to our MSF's about 15 years ago when the first narrowband date was proposed and we had replaced all our portables with MT-2000's anyway and it worked fine, we have since replaced the MSF's with Quantars that can legaly do narrowband. The retune and filters would have been fine a few years ago but now with the deadline being so close the only option is to replace non complying equipment with new stuff. THe MT's are also gone now replaced by XTS's.

Boy this narrowband thing has been a long time comming, it's here now and you need to deal with it properly.

By the way we had Minitor 2 and 4's that worked fine on 2.5, they are gone now also replaced by 5's

[k2hz]

Any of the Com-Spec kits I am aware of are strictly for receivers and do not claim to make a transmitter compliant. The FCC has made it very clear that conversion kits for transmitters are not acceptable like they did allow years ago for 15 to 5kHz deviation "narrow banding".

I have used the Com-Spec Micor kits to narrow band Spectra Tac receivers and they work very well for that purpose. They were also a temporary solution during the last several years of transistion when voluntary narrow banding by reducing deviation under a wide band license was legitimate until narrow band becomes compulsory.

[RADIOMAN2002]

For MASTR III stations the kit would make it compliant, since the radio already has a N.B. designation, but the early versions had W.B. receivers. The kits will work on any receiver since they don't have a requirement for N.B. certification. The only legal use of a MSF 5000 after next January is Ham or GMRS, or sell to it someone in Canada, they don't have that N.B. problem.

[desperado]

For MASTR III stations the kit would make it compliant, since the radio already has a N.B. designation, but the early versions had W.B. receivers. The kits will work on any receiver since they don't have a requirement for N.B. certification. The only legal use of a MSF 5000 after next January is Ham or GMRS, or sell to it someone in Canada, they don't have that N.B. problem.

The MASTR 3 had 2 different type acceptance numbers, depending on serial number. The MASTR 3 was an odd bird in that it would even program narrow but would not generate 2.5 Khz deviation in some early models. This is all from MA/COM directly and the only way to know for sure is call them with the FCC ID and serial number of the unit.