MX1000/Saber 1 - a few questions

[g8tzl2004]

I have an MX1000, the European version of the Saber 1. The set covers 440-470Mhz. I have RSS version 02.04.00 which should work OK with a 486 laptop running pure DOS. Here are my questions:

- Does anybody have any views on the MX1000 RX sensitivity at 430-433Mhz?? I have read that the Saber 1 can only work about 6 MHz out of band. I plan on using the MX1000 about 7-9 MHz out of band? I have previously hex edited the RSS for a 438-470MHz GP300 down to 430MHz and that has excellent sensitivity 8 MHz out of band!!

- How do you program the 3 side keys? I've looked through the RSS but can't figure it out. At the moment, the top side button is programmed as CTCSS/PL defeat. I want to set it to squelch open ie white noise. The bottom 2 side keys just bleep - I don't think they are currently programmed.

- Is it possible to have a scan option with the MX1000?

As a note to others, there is a European ham version of RSS 02.04.00 where the band limits have already been extended down to 430MHz from 440MHz. BUT, the RSS is just in one big folder - for the RSS to work you need to create 5 sub folders and copy the relevant files into each folder!!! When I did this , it worked OK. I used an earlier unmodded version (R02.02.00) to work out the required sub folders. However, I will initially use an unmodded version of RSS to initially program the MX1000 in order to safely extract the original codeplug before experimenting

Thanks

[Tom in D.C.]

I can help you with three of your questions:

1. Your MX1000/Saber I will not scan, ever, even though in the case of
the Saber I the ID number might end in "CN" which indicates a scanning radio.

2. The top button is a monitor button. Go into you RSS and change the
setting of Silent Monitor to OFF, then you'll hear noise when you push the
button. If you're hearing transmissions but no noise the Silent Monitor is turned on.

3. The other two buttons at the bottom, below the PTT button, are used
for emergency signalling only, which means they're seldom used. In the
Astro Saber radios they can be programmed to initiate scanning and other
things but in the standard Sabers they're just for signalling.

Hope this helps. Others will jump in to help with your other questions.

[g8tzl2004]

Tom - thanks very much for the feedback.

When you say the bottom 2 side buttons are used for signalling, does this mean that they can be used to generate a 1750Hz tone burst? The European version has "5 tone/selcall" capability but I think it also does a single tone?

A couple of other questions:

- can you just have TX CTCSS/PL encode (ie NO RX decode)?
- if you select CTCSS encode , do all channels need to have a CTCSS encode tone , or can you just leave some channels with no CTCSS?

Thanks

[Tom in D.C.]

[quote="g8tzl2004"]Tom - thanks very much for the feedback.

When you say the bottom 2 side buttons are used for signalling, does this mean that theycan be used to generate a 1750Hz tone burst? The European version has "5 tone/selcall" capability but I think it also does a single tone?
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I don't know the answer to that; they're called RAT buttons which stands for repeater
access tone. Look at you RSS's features list and see if these are listed.
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A couple of other questions:
can you just have TX CTCSS/PL encode (ie NO RX decode)?
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Yes, you can have CTCSS/PL encode and CSQ decode on the standard Saber.
---------------------------------------------------------------------------------
- if you select CTCSS encode , do all channels need to have a CTCSS encode tone , or can you just leave some channels with no CTCSS?
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No, CTCSS/PL is selectable by channel, either transmit only, receive only, or DPL which
is almost always both--or just CSQ tx and rx.
---------------------------------------------------------------------------------
Again, all of my experience has been with the versions 6 and 7 of the standard Saber RSS.

Regards,

[g8tzl2004]

Thanks again!! Saber RSS is definately not as user friendly as newer stuff

More questions :

- Do you actually need to align the radio when you change freqs ie. tweak VCO, TXCO, Warp Osc etc?? The current freqs are around 461Mhz so I will be moving down in freq by around 30MHz to 431-433Mhz.

- Are there any other things I need to watch out for when programmimg a Saber I ?

- Is there a Programming/Alignment guide floating round the internet - I can't find anything and the Help Pages in the RSS are not that clear!!! Will save me asking lots of basic questions!!!

Thanks

[g8tzl2004]

I've just found "Saber Portable Radios RSS User Guide" - over 100 pages of useful info

[Tom in D.C.]

Many of the modular chassis components in the Saber and MX radios have a limited
bandwidth and will not operate at all outside those limits, so your intended 30 mHz
excursion may be difficult to achieve. However, with study of those components you
can get the correct ones for your new frequency range and change them out. The
only overall problem is that these radios are no longer manufactured so you'll have to
find secondary sources for the parts, which would include cannibalizing other radios
for the right subassemblies.

[g8tzl2004]

Thanks Tom - my MX1000 is currently programmed on 461MHz BUT the set covers 440-470MHz. I am only planning on extending the freq range down to around 431-433MHz ie 7 to 9 MHz out of band.

Hopefuly the MX1000 will not be completely deaf at 431MHz. However, I'm not sure whether I will actually need to realign the radio given that the current freq is 461MHz??

With US Saber UHF sets , when you put them on the 440MHz ham band , do you need to start tweaking SQ , VCO , Osc warp settings etc OR do you just program in new freqs ?? I am still trying to understand the RSS but it looks like there is an option to "Extract Tuning Data Out of Radio" - if you select Yes , then the Programmer will use existing values rather than default value???

73

[Tom in D.C.]

Pushing a 438-470 mHz (the actual specified bandsplit) to 431 mHz is just over the line
for making the unit work at that frequency, and it probably will not work unless it's realigned.

As for your second question, when you program the radio the RSS will ask you if you want to use the tuning values in the codeplug you've written OR the tuning values that are currently in the radio. If you're working within the radio's specified bandsplit you probably always want to stick with the tuning values already in the radio. In your case, if you're trying to jump down to 431 mHz you probably have to have the radio realigned anyway so which setup you use does not make any difference.

Best way to get to 431 mHz with a Saber these days is to get a US-spec 403-433 mHz Saber. They are really cheap and readily available. I use one for monitoring repeater links in my area
that are on 420/425 mHz for both 440 and 927 mHz repeaters.

[Keygun]

UHF-MX1000 radios are very "friendly", but below 433/434MHz sensitivity starts to suffer.
TX will do 431MHz fine. No problem with unlocking VCO`s. So duplex/repeater frequencies
are no problem; simplex-frequencies on the lower end of the band are. If you really need
simplex-frequencies that down below, better look for a UHF-low-split radio.

It is possible to programm the two buttons which are located below the PTT with Singletones,
Select 5-sequences or a mixture. First you have to define the needed singletone via option
H742. Then enter option H692. The sequencial for a 1750Hz singletone is always
J. Don´t forget to adjust the duration. I never had any problems with a duration of
1500ms.

For the second call-button the Option "Call Code" can contain a Select5-sequence or another
singletone, "K" for example, which is 2135Hz.

After programming the new frequencies you have to check/retune Squelch-sensitivity, Deviation-
linearity, output-power and reprogram the radio. Thats all. MX1000`s are excellent pieces of radio.

Keygun

[g8tzl2004]

Thanks Tom/Keygun

Keygun - UK repeaters have a new "widespaced" allocation eg. 430.900MHz RX and 438.500MHz TX. The old allocation at 433.000MHz RX and 434.600MHz TX should hopefully definately be OK - as well as simplex at 433.5Mhz.

Thanks for the info on the tone burst keys - very useful - some UK repeaters still use 1750Hz access .

Is power output realignment critical? My MX1000 is currently TXing on 461MHz. I was hoping I could just build a simple programming cable (GND, pin 3 and 6) without having to include an external antenna connector for power alignment. There is no GND connector on the set top antenna socket - so all I can really use is a simple relative power meter.

Is there any risk in just leaving the output power setting at the 461MHz level? ie. will I be running too much or hardly any power at 431/433MHz?

[Keygun]

Hi.

The MX1000/Saber PA-modules are extremely widebanded. I`m always
impressed to see, how far they can go behind their official band-limits.
So there will be not too much difference in output power between 431MHz
and 461MHz.

But it is useful to know the exact actual outpower. Some guys tending
to crank up the power till the radio is glowing in the dark. Keep always
in mind: There is not much inside the radio, which can be used as an
adequate heatsink for the PA.

On my personal radios i keep the output power as low as possible:
1 - 1.5 watts on low-power models and 2 - 2.5 watts on high-power
models. That is enough for stable communications. A nice side-
effect: I can use those beautifull small NiMH batteries. Not to mention
that i never had a problem with a fried PA-module.

Keygun

[g8tzl2004]

Thanks Keygun.

I have now successfully programmed the MX1000 onto 70cms Sensitivity at 433.0 MHz is OK - maybe 4/5dB down from my most sensitive set. At 430.9 MHz , sensitivity is well down - but would still be OK for a local repeater.

My MX1000 is a low power 12.5KHz submersible radio - model H34SAN9509_N from the RSS and MDH34YBN9509AN on the back of the radio.

The MX1000 is aligned as follows:

High Power- 1A
VCO Mod - 0D
Ref Osc Mod - 07

I have increased the mic gain to +6db (it was originally set to -3dB!!). However, the dev is still a bit low - especially given that UK repeaters are 5Khz dev/25KHz spaced (not 2.5KHz/12.5KHz).

Do you have any "typical" values for ham freqs for the VCO Mod and Ref Osc Mod to increase the dev to , say , 3.5KHz??

Also, any typical values for TX power - does 1A = 2W?? If so , what is a typical setting for 1.5W? I used a homebrew prog cable which does not have an external antenna connector for power measurement!!

Thanks 73

[Keygun]

Hi.

There is no such thing like "typical values". The values differ from radio to radio. The maximum setting for deviation (7F)should give you something betwween 3.5 and 4kHz of deviation on narrow-band radios. But this should be verified with an service monitor.

Maybe the radio was used in a noisy envirenment, so a gain of -3db was OK for that use.

Keygun

[g8tzl2004]

Any idea if I need to change the Ref Osc Mod value (currently 07) when I increase the VCO Mod (currently 0D)?

Thanks

[Keygun]

Let alone the Reference oscillator! If it is once set correctly, no more to tweak there!

Keygun

[g8tzl2004]

Its the Ref Osc "Modulation" adjustment not the Ref Osc (ie. used for freq tweaking).

The Ref Osc Modulation and VCO Modulation adjustment seem to be linked and adjust the dev and mod.

Can I just leave the Ref Osc Modulation DAC setting the same and just adjust the VCO Mod for getting higher deviation?

Thanks

[Keygun]

OK, it seems i need new eyeglasses.

The Ref Osc Modulation setting has to do with signallings
(PL or DPL for example), and is used to adjust them for
clean waveforms. On older radios it is called "Compensation".
So also no retuning necessary.

Keygun