I'm looking at doing some site linking/reporting in the licenced 931/942 band.
Is there any legal mobile radio type product available?
I'm open to Motorola, Kenwood, Icom. I only need 5 to 10 watts TX power. Needs to TX 931 and RX 942 (or reverse). narrowband.
Thanks for any suggestions.
Any radios (Motorola or other) that are legal in 931/942 bands?
Moderator: Queue Moderator
Re: Any radios (Motorola or other) that are legal in 931/942 bands?
For Motorola probably your best bet is to review this portable and mobile gear.
http://www.qsl.net/kb9mwr/projects/900mhz/plan.html
http://www.qsl.net/kb9mwr/projects/900mhz/plan.html
fineshot1
NJ USA
NJ USA
Re: Any radios (Motorola or other) that are legal in 931/942 bands?
Hello:
I'm actualy doing a mod on a maxtrac 900 privacy plus trunking mobile to the 33cm ham band now.
Maxtrac 10/10/10 and is a 12 watt mobile.
In the earlier stages of the modification I did do testing on 931 MHz tx and rx both and radio with out mods just blanked and reiniated as a 16 ch conventional with scan the rx at 931 was decent sensitivity that I personaly wouldn't have done any improvements on as it was pretty good.
Tx at 931 MHz from my 12 watt mobile actualy hit 12 watts on my bird watt meter so spot on .
At 941 MHz I still had decent rx sensitivy at 941 MHz but tx wattage did drop to 7 1/2 watts but probably could have turned it up but didn't bother trying as I was headed to full tx/rx rights from 902 thru 928 MHz as my ending mod.
So I have since modified my steering voltage to get tx wattage of 14 watts 902 thru 928 MHz but also had to mod the vco pin shift to allow middle tx freqs from 903 MHz up to and thru 929 MHz to tx and txd rest of the way to 941 MHz where my test sheet info shows me where I stopped testing .
I was able to eventualy get rx from 902 to 941 MHz but only after removing the factory rf front end murata filters which stopped rx at aprox 903 MHz rx until up around as I recall about 929 or 930 ish.
Ham toko filters opened up the rx so all was good for a entire 902 thru 941 rx per my tesing results.
The tx was in the 903 and below till you got up to 930 MHz as factory but vco mod for pin shift gained the 902 to 941 tx plus the steering line voltage was needed to get radio to lock up on freq.
A bit of a task but can be done if you really want a maxtrac on the 900 Mhz 33cm ham band.
But again as factory no mods other than I turned the radio into a 16 ch conventional the radio as was did tx/rx at 931 MHz with decent results and also tx/rx at 941 MHz was decent as well.
931 mhz tx wattage without adjusting was 12 watts on my radio and 941 MHz without adjusting came in at 7 1/2 watts.
Id definitely keep the 10 MHz split from rx to tx thoo and factory spread actualy is more than 10 MHz and for a good reason id suspect.
Its my understanding that originaly the ham 900 band was set up for 12 1/2 MHz spread and most I'm told don't do 12 1/2 MHz but rather 25 MHz spread for seperation to get better results which I'm inclined to agree with myself.
Id consider if it works out for you to add what id think will be much appreciated tx to rx spread larger than your proposed 10 MHz unless you have one heck of a good low noise floor and duplexers to give you the rejection youll need.
I think I could do it though as you spec but be tougher to do but could do it I think.
The 942 MHz tx or rx you spec is within the factory 900 MHz maxtrac radio as is .
The normal factoru spec for tx /rx on talk around is 935 MHz to 941 MHz so that ones in spec.
However your 931 MHz tx and rx are 4 megs outside the factory normal specs but as I stated my testing still reached down to 931 MHz as was.
Only thing I could see might be other radios might not lock up down to 931 MHz but if so then adjusting the steering line voltage should correct the issue .
My radio steer line voltage for 931 rx was 1.68 volts with 931 MHz tx steer line voltage reading 1.95 volts.
So my lowest freq steer line voltage per my testing to get radio to work was 1.68 volts on 902 mhz but no higher than 4.8 volts on my highest tx freq which was 941 mhz.
So if you were to program your radio for middle of spread at 921.500 MHz the tx voltage should be aprox 1.81 volts id suspect as an aprox value.
I not sure why now I went through all the mods to do the ham 900 now as theres not much for 900 ham around me but I had the itch to give it a whirl for just wanted to do it .
So sold the one have another to the point of mods for ham repeater inputs and outputs and simplex and simplex radio to radio 902 to 903 tx and rx 927 to 934 at the moment so if I'm wanting full tx /rx from 902 thru 934 ill need to do the pin shift mod too.
But that's where I have progressed to thus far until I look at it later.
Satelite
I'm actualy doing a mod on a maxtrac 900 privacy plus trunking mobile to the 33cm ham band now.
Maxtrac 10/10/10 and is a 12 watt mobile.
In the earlier stages of the modification I did do testing on 931 MHz tx and rx both and radio with out mods just blanked and reiniated as a 16 ch conventional with scan the rx at 931 was decent sensitivity that I personaly wouldn't have done any improvements on as it was pretty good.
Tx at 931 MHz from my 12 watt mobile actualy hit 12 watts on my bird watt meter so spot on .
At 941 MHz I still had decent rx sensitivy at 941 MHz but tx wattage did drop to 7 1/2 watts but probably could have turned it up but didn't bother trying as I was headed to full tx/rx rights from 902 thru 928 MHz as my ending mod.
So I have since modified my steering voltage to get tx wattage of 14 watts 902 thru 928 MHz but also had to mod the vco pin shift to allow middle tx freqs from 903 MHz up to and thru 929 MHz to tx and txd rest of the way to 941 MHz where my test sheet info shows me where I stopped testing .
I was able to eventualy get rx from 902 to 941 MHz but only after removing the factory rf front end murata filters which stopped rx at aprox 903 MHz rx until up around as I recall about 929 or 930 ish.
Ham toko filters opened up the rx so all was good for a entire 902 thru 941 rx per my tesing results.
The tx was in the 903 and below till you got up to 930 MHz as factory but vco mod for pin shift gained the 902 to 941 tx plus the steering line voltage was needed to get radio to lock up on freq.
A bit of a task but can be done if you really want a maxtrac on the 900 Mhz 33cm ham band.
But again as factory no mods other than I turned the radio into a 16 ch conventional the radio as was did tx/rx at 931 MHz with decent results and also tx/rx at 941 MHz was decent as well.
931 mhz tx wattage without adjusting was 12 watts on my radio and 941 MHz without adjusting came in at 7 1/2 watts.
Id definitely keep the 10 MHz split from rx to tx thoo and factory spread actualy is more than 10 MHz and for a good reason id suspect.
Its my understanding that originaly the ham 900 band was set up for 12 1/2 MHz spread and most I'm told don't do 12 1/2 MHz but rather 25 MHz spread for seperation to get better results which I'm inclined to agree with myself.
Id consider if it works out for you to add what id think will be much appreciated tx to rx spread larger than your proposed 10 MHz unless you have one heck of a good low noise floor and duplexers to give you the rejection youll need.
I think I could do it though as you spec but be tougher to do but could do it I think.
The 942 MHz tx or rx you spec is within the factory 900 MHz maxtrac radio as is .
The normal factoru spec for tx /rx on talk around is 935 MHz to 941 MHz so that ones in spec.
However your 931 MHz tx and rx are 4 megs outside the factory normal specs but as I stated my testing still reached down to 931 MHz as was.
Only thing I could see might be other radios might not lock up down to 931 MHz but if so then adjusting the steering line voltage should correct the issue .
My radio steer line voltage for 931 rx was 1.68 volts with 931 MHz tx steer line voltage reading 1.95 volts.
So my lowest freq steer line voltage per my testing to get radio to work was 1.68 volts on 902 mhz but no higher than 4.8 volts on my highest tx freq which was 941 mhz.
So if you were to program your radio for middle of spread at 921.500 MHz the tx voltage should be aprox 1.81 volts id suspect as an aprox value.
I not sure why now I went through all the mods to do the ham 900 now as theres not much for 900 ham around me but I had the itch to give it a whirl for just wanted to do it .
So sold the one have another to the point of mods for ham repeater inputs and outputs and simplex and simplex radio to radio 902 to 903 tx and rx 927 to 934 at the moment so if I'm wanting full tx /rx from 902 thru 934 ill need to do the pin shift mod too.
But that's where I have progressed to thus far until I look at it later.
Satelite