33cm radio suggestions

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CommJunkie

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Are the only 900mhz radios out there commercial radios? I've seen the 220/900mhz portable out there from Alinco, but I was hoping for something mobile.
 

mmckenna

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There are some older radios (1990's era), I think Kenwood was one, that had a multi band mobile that you could install band modules in. I seem to remember they had a 900MHz and 1.2GHz module.

Might be hard to find.

While the commercial gear can be expensive to program, they usually are top notch radios. Newer ones often have a large number of memories and Operator Selectable Tone (OST) options that allow you to select CTCSS tones. Between the two you can enter enough simplex and repeater frequencies to cover a lot. Not the best solution for an Amateur, but it IS an option. I know a couple of Hams that are using Motorola 900MHz gear.

BatLabs.com has a section on their discussion board devoted to converting commercial gear to 900MHz.

Good luck on your search!
 

N4KVE

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Are the only 900mhz radios out there commercial radios? I've seen the 220/900mhz portable out there from Alinco, but I was hoping for something mobile.
When I spoke to the Alinco rep at the Orlando Hamfest he said they were considering making a 900 mobile radio similar to the single band mobiles they already make. I guess they want to see how many of the 220/900 portables they sell. GARY N4KVE
 

CommJunkie

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Thanks for the replies.

As I sit here thinking, it would probably be beneficial to buy an HT first, to gauge how active the band is before I spend the money on a commercial radio.
 

fineshot1

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There are some older radios (1990's era), I think Kenwood was one, that had a multi band mobile that you could install band modules in. I seem to remember they had a 900MHz and 1.2GHz module.

Might be hard to find.

While the commercial gear can be expensive to program, they usually are top notch radios. Newer ones often have a large number of memories and Operator Selectable Tone (OST) options that allow you to select CTCSS tones. Between the two you can enter enough simplex and repeater frequencies to cover a lot. Not the best solution for an Amateur, but it IS an option. I know a couple of Hams that are using Motorola 900MHz gear.

BatLabs.com has a section on their discussion board devoted to converting commercial gear to 900MHz.

Good luck on your search!
You must be thinking of the kenwood 641/642/741/742/942 series but there was never a 902-928Mhz
band module for that(at least not in the usa). Band modules - 10mtrs, 6mtrs, 2mtrs, 220, 70cm, 23cm
and there was a mod on the older 70cm band module to cover 800-1000Mhz RX also. There was a
band module from the Japan market for the 2.4Ghz band but supposedly you would have to do another
mod to get the usa models to recognize it.
 

AK9R

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The hams on 902 MHz in my area swear by the Kenwood TK-981 mobile. A Google search will turn up the necessary mods.
 

mass-man

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You can get a TK 981 mobile in the "around $100 range" or the same for the TK 481 HT. In my opinion cheap enuf to see if 900 interests you. If you go Kenwood you can get the programming software FREE, buy a $15 cable, hook it to a PC and off you go. As a matter of fact the TK 981 can currently hold ALL the 900 mhz repeaters in the country in memory. Not terribly practical, but doable.
 

mmckenna

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You must be thinking of the kenwood 641/642/741/742/942 series but there was never a 902-928Mhz band module for that(at least not in the usa).
That must have been it. My dad has one sitting in his garage he got from a friend. Couldn't remember if it had 900MHz or not. Thanks for the correction.
 

N4KVE

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You must be thinking of the kenwood 641/642/741/742/942 series but there was never a 902-928Mhz
band module for that(at least not in the usa). Band modules - 10mtrs, 6mtrs, 2mtrs, 220, 70cm, 23cm
and there was a mod on the older 70cm band module to cover 800-1000Mhz RX also. There was a
band module from the Japan market for the 2.4Ghz band but supposedly you would have to do another
mod to get the usa models to recognize it.
There was also an Icom IC 900A which had a control head, & modules which stayed in the trunk. On the Kenwood radios, you could only add 1 more module which was inserted in the radio. On the Icom, you could add 10, 6, 1.25 mtrs, & 23 cm, but not 900 MHZ.. The modules stacked on top of each other, & if the owner had enough cash, could have 6 different bands. All the band modules,& the control head were connected by fiber optic cables. I only ever saw 1 of these radios. Do you remember that radio Tom? GTX portables, & mobiles are under $100 now, & work great in the ham 900 portion w/o any mods to the radio. While they only have 10 memories each, there's not many places in the US that have more than 10 900 repeaters in 1 city. While the 981 has lot's more channels, they are only 12 watts, while the GTX came as a 12 or 30 watt radio. While the extra power doesn't do much on VHF, or UHF, it really does help on 900 to get over the noise caused by the baby monitors, & cordless phones. I do have a 30 watt MCS2000 type 3 coming to me this week for the car, as I do need more than 10 memory channels. GARY N4KVE
 
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Skypilot007

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Is there any hardware modifications or retuning that'seed to be done to the TK981 or TK481 for Ham band use? How about software modification to allow it down into the Ham band.

I've bee using a Motorola mcs2000 only because I have the software and from researching it seemed to be the only way to go without having to open the radio up or re-tune. There is a requirement to modify the programming software but its not that hard.

The mcs2000's do work very well on 900MHz, at least the two e-bay radios I have do.
 

k7ng

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Personally I use the kenwood TK-981 mobile/base and the TK-481 handheld. They are very well made and still in production, so you can get accessories and batteries for the portable. It requires Kenwood software to program them (same program, KPG-49, works for both, as well as all other TK-x80 models).
These radios are as close to 'Plug and Play' for the 900 band as there are.

Some people don't like the TK-981/481 because of the way the scan works, but I manage.

I have used the EF Johnson 242-8655 mobile radio also (MUCH older) but I don't like it due to some deficiencies in design.
 

k7ng

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I should have given more info the last post than I did.
Regarding the Kenwood TK-981, they do not theoretically require anything other than reprogramming to work just fine on the 902-928 MHz band. I have found that occasionally a radio might need to have the synthesizer VCO readjusted just a smidge - I have 5 and one needed it, another I did just because I wanted to keep the adjustment near the center of the window. There are several methods but really all you need is a DMM and a very very small jewelers' screwdriver. Several webpages have the technique. I put my radios in the freezer for a couple hours (after adjustment) and then check them to see if the VCO is still locked, then I wrap them in plastic and let them get fairly hot, after which I check again. If the VCO is locked at both extremes of temperature you're sure to be good to go.

TK-981's with serial numbers higher than 6 Million or so could possibly be adjusted to have higher output power than they come from the factory (again, there's a good webpage for the whole story), but in general I have found I don't need more than 15W that often. If you're used to 2M FM radio, you may be shocked and disappointed on how short a reach into repeaters you get from a handheld radio. 900 MHz portables run about 1 watt, not 5 or 6 like on 2M, and the attenuation with distance is hugely more on 900 than on 2M. But don't let that discourage you, you may find a repeater close to you that does great with a handheld.

But to state in agreement with mass-man, you should be able to get a mobile AND a portable for about the cost of a decent, new 2M mobile, and if you decide you don't want to do 900 any more, you should be able to sell them for about what you paid.
 

Skypilot007

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I should have given more info the last post than I did.
Regarding the Kenwood TK-981, they do not theoretically require anything other than reprogramming to work just fine on the 902-928 MHz band. I have found that occasionally a radio might need to have the synthesizer VCO readjusted just a smidge - I have 5 and one needed it, another I did just because I wanted to keep the adjustment near the center of the window. There are several methods but really all you need is a DMM and a very very small jewelers' screwdriver. Several webpages have the technique. I put my radios in the freezer for a couple hours (after adjustment) and then check them to see if the VCO is still locked, then I wrap them in plastic and let them get fairly hot, after which I check again. If the VCO is locked at both extremes of temperature you're sure to be good to go.

TK-981's with serial numbers higher than 6 Million or so could possibly be adjusted to have higher output power than they come from the factory (again, there's a good webpage for the whole story), but in general I have found I don't need more than 15W that often. If you're used to 2M FM radio, you may be shocked and disappointed on how short a reach into repeaters you get from a handheld radio. 900 MHz portables run about 1 watt, not 5 or 6 like on 2M, and the attenuation with distance is hugely more on 900 than on 2M. But don't let that discourage you, you may find a repeater close to you that does great with a handheld.

But to state in agreement with mass-man, you should be able to get a mobile AND a portable for about the cost of a decent, new 2M mobile, and if you decide you don't want to do 900 any more, you should be able to sell them for about what you paid.
I appreciate the information. Thank you.
 

krokus

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Adding to the theme, I would like to add 900 MHz SSB capability to the club VHF/UHF station. I have not seen many options for that; what are others using?
 

k7ng

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There is no 'one box' solution for 902 MHz Ham SSB.
Transverters are available using 28 or 144 MHz IFs, and the same manufacturers of the transverters make amplifiers up to the 100W level.
Transverters can also be homebrewed but without a large 'junk box' there won't be a significant cost savings in doing so.
There is no realistic conversion to SSB for commercial surplus 900 MHz FM radios.
 

krokus

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I figured a transverter was going to end up being the solution. I just have not approached the club, to see if there is a consensus on which way to go with it.

I guess this will be a project for next contest season, as I don't see it being done for this year.
 
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