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Looking for old Batboard review of 900MHz radios ???

This forum is for the discussions targeted at converting various models of Motorola equipment to operate in the 900MHz Amateur Band.

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g8tzl2004
Posts: 1082
Joined: Wed Sep 08, 2004 10:13 am

Looking for old Batboard review of 900MHz radios ???

Postby g8tzl2004 » Wed Mar 26, 2008 6:39 am

I've been searching but cannot find a very useful Batboard review of the RX/TX performance of different 900MHz radios - GTX / LTS2000 / MCS2000 etc etc.

Have early posts "dropped off the end" or am I not looking in the right place??

Thanks
Last edited by g8tzl2004 on Thu Mar 27, 2008 6:57 am, edited 1 time in total.

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MSS-Dave
Posts: 767
Joined: Mon Jun 30, 2003 6:02 pm
What radios do you own?: XTL5K, NX300, PD782, Spark Gap

Re: Looking for old Batboard review of 900MHz radios ???

Postby MSS-Dave » Wed Mar 26, 2008 10:59 am

g8tzl2004 wrote:I've been searching but cannot find a very useful Batboard review of the RX/TX performance of different 900MHz radios - GTX / LTS2000 / MCS2000 etc etc.

I think it was done by kcbooboo a few years ago.

Have early posts "dropped off the end" or am I not looking in the right place??

Thanks

I think this is what you are looking for.....

http://batboard.batlabs.com/viewtopic.php?f=3&t=21222

Dave

g8tzl2004
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Joined: Wed Sep 08, 2004 10:13 am

Re: Looking for old Batboard review of 900MHz radios ???

Postby g8tzl2004 » Wed Mar 26, 2008 12:54 pm

Thanks - but unfortunately the start of the thread (with the review) seems to be missing !!!

Batwings21
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Re: Looking for old Batboard review of 900MHz radios ???

Postby Batwings21 » Wed Mar 26, 2008 1:09 pm

All of r0F's posts were removed at his request leaving wonderful holes in the board.

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MSS-Dave
Posts: 767
Joined: Mon Jun 30, 2003 6:02 pm
What radios do you own?: XTL5K, NX300, PD782, Spark Gap

Re: Looking for old Batboard review of 900MHz radios ???

Postby MSS-Dave » Wed Mar 26, 2008 4:29 pm

Sorry 'bout that. I remembered the title and found it. Just didn't click to read it again.. there was some great info in there, lots of time spent on testing for sure.

Dave

fineshot1
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Joined: Wed Oct 12, 2005 5:13 am

Re: Looking for old Batboard review of 900MHz radios ???

Postby fineshot1 » Wed Mar 26, 2008 4:45 pm

OK - I am not not sure but the below thread I saved may be what you are looking for. I hope its ok for me to re-post. see below:

At 01:21 AM 10/14/2004, you wrote:

>Well we got a pair of GTX mobiles working now. (Thanks for everyones help).
What I now wonder (since I don't have access to a service monitor) what are
some typical receive specs on this radio in various parts of the ham band.
>


Well, it's been a busy week. All sorts of testing and hacking going on. Myself
and a group of experimenters have been busy playing up on the 900 MHz ham band.
Our prerogative was to determine if it was worth putting up a 900 MHz repeater
in town.

Our initial test involved GTX, and MTS2000 portables. Both had been aligned to
TX approx 2.9W in the 927-928 MHz area. Sensitivity tests yielded average
results of 0.19-0.22uV for 12dB SINAD. Myself and another member of the group
made arrangements to "borrow" the roof of the tallest building in town, which
is about 430 feet up. The other participant went out for a drive in his vehicle,
with the MTS2000 using a duckie. How did we fair? Not bad actually. We found
that 900 MHz worked FULL QUIETING right up until the line-of-sight factor
hampered us. We managed to talk from Winnipeg to 5km north of an indian
reservation called "Scanterburry". This is about 65km as the crow flys. (Maybe
40mi or something?) The mobile station was able to use the low-power setting on
the MTS2000 for 1W and talk back to us. Very impressive.

I've been using a Motorola R-2001A service monitor to set everything up, and
measure specs. Here's what I've found so far:

- GTX Portables -

Very reliable for the most part. Sensitivity is typically better than 0.25uV for
12dB SINAD. Most times around 0.20uV. I've had one so far out of 10, that is
completely deaf. I suspect a hardware issue with this one, as they are all used/
ebay radios. TX power is easily set up for 2.5-3.0W output for 927-928 MHz, and
they also yield 2.0-3.0W in the 902-903 MHz repeater input area. (We use 927-928
MHz for talk-around, as the radios are COMPLETELY deaf in 902+ MHz Sensitivity
picks up again (sharply) at 926 MHz, but it's not acceptable until about 927.4MHz)
We were aiming for deviation of about 4.0 - 4.5 KHz through the 902-903 MHz
spectrum, and 927-928 MHz. They aren't stable in this regard, and the best I've
been able to do is 4.2-4.3 KHz deviation for 927-928, and 2.3-3.4 KHz in the
927-928. That's still not too bad. You can set them up for 4.5 KHz deviation in
902-903, but then it's either over deviated in the 927-928 MHz area (10KHz!!)
or under deviated. (less than 1KHz)

- GTX Mobiles -

They are about the same as the portable. I've been able to get 11.2W - 13.0 W TXPO
for 902-903 and 927-928. Deviation is slightly more stable (avg of 4KHz) and
sensitivity is about 0.25uV for 12dB SINAD. Again, they are DEAF on 902-903 MHz,
but it doesn't matter as this is repeater input spectrum.

- MTS2000 -

This portable has proven to be slightly more tricky to set up. They have issues (so
far) with squelch hanging open, or being too high, regardless of what I do in the
soft-pot menus. We use tone-squelch, so it's not that big of a problem. Deviation
is low with the built-in mic, but is fine with a speaker-mic. It's almost as if the
gain for the built-in mic is disabled. Yes, I've checked/played with the gain
settings in the service menu. No go. TXPO is a healthy 2.9W, and sensitivity was
0.26uV for 12dB SINAD. "Stable" deviation (across the band) is about 3.4 KHz. Good
enough - we can always turn it up later, and sacrifice talk-around once the
repeater is up.

- MCS2000 -

Now this radio IS THE BOMB. I've been working on a 25W version over the last 24
hours. It is by far, the best sounding beast I've played with. The audio quality on
this thing is killer. It is a model I. I had to do a few mods to it to get it to
operate how I wanted, but they weren't scary. First of all, I didn't have an
accessory plug, so I had to get the service/install manual, and look at the pinout.
I had to jumper pins 1/2 to get the internal speaker working, 4/9 to disable the
"tx on powerup" issue (emergency button) and I installed a jumper in the control-head/
faceplate to always enable the mic hang-up feature. This enables the tone/dpl decoder
at all times. Ready for this? TXPO on 927-928 MHz was 31.8W. TXPO on 902 MHz was
slightly less, around 24W. The only issue was with the squelch, which seems to have a
lot of hysterisis, regardless of how low I go (improvements noted) with the squelch
level. If I set squelch to open for 12dB SINAD, it won't close until the signal is
completely gone. If I turn it up a value or two, it gets really tight, and won't open
until I inject a signal of about 0.4uV. I set it for the lower value, and we use
tone-squelch, so no big deal. The radio is DEAF at 902-903. Sensitivity was 0.19uV
for 12dB SINAD at 927.5 MHz, so it's a decent beast. Deviation is about 4.0 KHz, and
stable. It sounds AWESOME with a desk-mic.

- LCS2000 -

This radio sucks. TXPO on the inputs (902-903) is a max of 5.6W. Sensitivity at 927-
928 is about 0.33uV for 12dB SINAD. Deviation is not stable (I can get it to 4.1 KHz
on the talk around, but it goes from 1.8 KHz to 11 KHz in one digital pot setting
increment) Further exploration is needed before we use this radio. Hardware mods too,
most likely. I was kind of surprised, as I thought it was basically a GTX. Maybe it's
a bad radio?? I only have one to work on, so I can't play with any more.

- LTS2000 -

Another disappointment. I thought it was going to be a great HT, but the sensitivity is
about 0.36uV for 12dB, and TXPO while good on talk-around (2.4W) is only 0.8W on the
902-903 MHz repeater input spectrum. Deviation was low too, in the order of 1.8 KHz.
More experimentation is needed with this HT before we make use of it.

Anyway, the MCS2000 is a killer base-station/mobile, and the GTX portables seem to be
really decent for the most part. If any of you guys are getting in to 900 MHz, those
are the killer radios. The GTX mobile also performs quite well, but has lower TXPO. I
haven't tested any spectras yet, but I hear they can get quite sensitive after some
basic mods.

Next week is a bigger test. We're hauling up the MCS2000, and connecting it to a 21dB
omni at 450+ feet (tower on the roof) and doing another range test. This should be fun,
and I'll keep you guys updated.

900 MHz is working out better for us than 440 MHz, in terms of range. Play people, play!

Shaun
fineshot1
NJ USA

g8tzl2004
Posts: 1082
Joined: Wed Sep 08, 2004 10:13 am

Re: Looking for old Batboard review of 900MHz radios ???

Postby g8tzl2004 » Thu Mar 27, 2008 6:34 am

Many thanks - its exactly what I was looking for !!

Pity that the original was removed - I'm surprised that informative posts which are a useful reference source are allowed to be removed !! The original author should be proud of his post !!

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W6JK
Posts: 339
Joined: Mon Jan 31, 2005 7:18 am

Re: Looking for old Batboard review of 900MHz radios ???

Postby W6JK » Thu Mar 27, 2008 8:49 am

This brings up a question I've been pondering. These are all 2.5 kHz radios, but every once in a while I run into someone who wants his to do 5 kHz. I think that's silly, and don't want any part of it, which really seems to annoy these guys. I realize they're not in L.A., but what are they going to do when the coordinator puts someone on the adjacent channels some day? And why do they want to put up with modulation acceptance issues in the mean time? It might work OK when the signals are full quieting, but hams usually want to be able to work with weaker signals too and that's going to be a problem. Not only that, but if you're a tiny bit off frequency, the problems are magnified. So what gives?


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