PL/DPL/CSQ Detect on Spectra

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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w1ksz
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PL/DPL/CSQ Detect on Spectra

Post by w1ksz »

Can you set one of the accessory pins on a Spectra (900 MHz) for a PL/DPL/CSQ Detect output ? I need to get a switch in output state to drive a PTT circuit.

Thanks, Dick, W1KSZ
thehead7
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Joined: Wed Oct 22, 2003 4:35 pm

Post by thehead7 »

Dick,

This can be done, but not through the RSS. I've got the receiver for my 900 machine doing that, but I had to place some internal jumpers. I've actually got it coming off of the audio enable line. I can give details if you like...

-John
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k4wtf
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Post by k4wtf »

I'd love to hear more about this. Where are you grabbing the audio as well?

Thanks,

John
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thehead7
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Post by thehead7 »

k4wtf wrote:I'd love to hear more about this. Where are you grabbing the audio as well?

Thanks,

John
John,

It looks like I may be doing this on a couple of A4 spectras for a link in the VERY near future. I intend to document everything with pictures and post it here.

You have to sacrifice a VIP pin, for one. The next part is, in essence, installing the "Data" option of the spectra, which involves moving around some 0 ohm jumpers on the command board... You can either have straight detector audio passed out, or audio that is de-emphasized.

Some spectras come this way. All of about 28 E7 900 spectras that I've been working on seem to have this option already. You might look at what spectras you have and probe their Det Audio line on the accy connector with an oscilliscope and see if you can see the static. If it's there, you've got the option, and should at least be able to triger ptt from the rear as well, possibly even TX Audio (as opposed to mic hi, which I believe to be there on all spectras, could be wrong).

Anyhow, if there's interest, I'll write up a page on the conversion process and post it on a web server somewhere... It could probably be useful, as It seems that every several weeks or so someone has this question.

Oh, just a quick off-topic note: K4WTF, now that's an outstanding call (leave it to a fellow gun-club alumnus to come up with that...)

Oorah
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k4wtf
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Post by k4wtf »

Great. I look forward to the documentation. What I want to do (I know - this is way overkill but) is take two 900Mhz spectras and put on one side of a rick and be able to switch them selectively between my other VHF and UHF spectras. This would allow me to:

(1) Put some energy into the air on the 900Mhz amateur band. Use it before we use it.

(2) Use my MTX9000 to get on VHF/UHF.

The reason for the TWO 900Mhz spectras is that I want to be able to preempt from the MTX9000 side so, a "transceiver" on the 900Mhz side won't do. It has to be a duplex operation or I can't preempt.

Anyway, does this sound like a pipe dream or is it "do-able" given the proper motivation and a bit of time?

Oh, and Oorah right back at ya Marine.

John
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thehead7
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Post by thehead7 »

John,

This is doable, however this is not neccasarily the way to go. If you already have a RICK, I'd say go for it, but the circuitry to make everything work together would be pretty simple... Of course, I think the RICK can be configured to work without a DPL detect line, it would just sense the increase in audio output or something. I'd have to look into that a bit more...

I'm planning on doing something similar. I want to use the 900 spectra in my car to crossband to either VHF or UHF on a syntor 9000. It can do this as a transceiver just fine, though. I'm also debating whether to do some more extensive hardware hacking to be able to change modes on all of the radios via DTMF sequences. That's a bigger, better, and later project though.

I'll keep you posted on my progress.

Stay Motivated,
Head
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