Motorola Low-Band Syntor X

[joefoss]

I have a Low-Band Motorola Syntor X. It works fine. I have it connected to a PIEXX software which changed-out the personality board and was replaced with the PIEXX equivalent so you can control the Syntor frequency range and scan via a lap-top computer. All works well 29 to 53 Mhz. However, I want to take one down to 25 Mhz. No one make any equipment there anymore. I am able to get the Syntor to operate as low as 26.10 Mhz. It would seem easy to get that to move one Mhz. lower. There is nor VCO adjustment as there is on the GE rangers to change ranges with a slight tweek. I would guess that if I were to program the factory EE Prom, the radio would only get it to 26.10 Mhz as well. I be leave the problem is in the VCO. There are a lot of good business frequencies on 25 Mhz I would like to monitor; many radio broadcast remotes operate there as well as some old business users who have kept their old radios. This is a good day-time frequency where you can communicate hundreds of miles (constant skip). Can anyone help me to get this unit on 25 MHz or on the 24 Mhz ham band? Thanks,
Joe
WD8BVL
Battle Creek, MI

 

[kd7kdc]

FM is not allowed below 29 MHz.

 

[mancow]

Sure you can, as long as you don't exceed 3kHz.

 

[joefoss]

Syntor X Range Extension.

FM is allowed in the commercial 25 Mhz bands as well.

 

[mm]

24.985MHz FM is being used daily by hams across the US and has been for years.

 

[joefoss]

Is this 24.985 wide or narrow FM?? Thanks,
Joe

 

[nd5y]

24.985MHz FM is being used daily by hams across the US and has been for years.

That would put part of their signal outside of the ham band which ends at 24.99. Not a good idea.

 

[joefoss]

Syntor X

Why a bad idea??. The Syntor is a fine monitor receiver, especially so with a properly tuned noise blanker.
Joe

 

[nd5y]

Why a bad idea??. The Syntor is a fine monitor receiver, especially so with a properly tuned noise blanker.
Joe

I has nothing to do with the quality of the radio.
If you are running 3 kHz deviation with the audio frequency limited to 3 kHz your signal is about 12 kHz wide.
If your carrier frequency is only 5 kHz from the edge of the band then part of your signal will be outside the ham band.

 

[joefoss]

Syntor X

Yes, I see. Therefore, on that ham band, you will have to stay with the new narrow-band standard of 2.5 or 3 Khz max, which is a 12 Khz bandwidth in order t stay within the defined band plan. Got it!
Joe

 

[kd7kdc]

Syntor X radios run at about 5kc deviation, they were not designed for 2.5kc deviation and with that being the case your looking at at least 20kc wide signal.

Transmitting a radio signal outside of your band privileges is not only bad practice, ill advised but illegal.

 

[mmckenna]

Back to the original question:

Shifting the VCO. I don't know about the low band units, but I used to have a VHF Hi Band unit with the Piexx controller. There was a VCO strip that had to be cut or lengthened to stretch the VCO to work down into the 2 meter ham band. I lost some of the top end, but I seem to recall it covered the 154MHz work frequencies just fine, as well as down into the 145MHz range just fine. I don't recall exactly, as it was many years ago.

Again, not sure if the low band unit is set up the same way or not, but it might be worth some research.

 

[joefoss]

Syntor X

I can easily cut back the deviation. If needed, I can change on the filter for a 2.5 Khz band pass. I have been receiving 2.5 KHz on my VHF unit with slightly reduced audio. I do not have the low-band manual, but I think the VCO is the same. I don' care about the higher frequencies. 10 meter is as high as I want to go on this one. I do have one all set up for 6 & 10. Seems these Syntors work very efficiently on 10 as I am getting out about 125 Watts with 90 watts on 6. I think I will adjust the final filter so it will pass the 6 meter power better. Thanks for the input.
Joe

 

[mmckenna]

Yeah, I knew a guy that had one of those in his truck running 10 meters and 6 meters. Nice set up if you can deal with the limited channel capacity.
I remember tweaking my VCO pretty easily and it turned out well. Hope it works for you!

 

[mancow]

In my opinion the X9000 is the best product they have ever built. I wish I was as talented as some here at coding. I would love to see an Arduino or Netduino interface with a remote display like the Uniden project. Coupling a modern user interface with these things things would be amazing.

 

[mmckenna]

Yeah, except they weigh a ton, and I can't even begin to imagine where you would mount one in a modern compact car. Those things were great when cars had a trunk the size of a small apartment. Dropped one on my foot once. Really lucky I didn't break all the bones in my foot. Ended up walking funny for a few days though.