Batboard

http://www.storm.ca/~nand/990/RICK/rptr.pdf

The above link is for a simple “RICK” interface that nearly anyone can build for under $10.00. It has excellent audio if properly adjusted. Actually, it can be adjusted to “taste” if you like. Keep the wiring less than 12 inches if possible. Shielded wire generally is not needed.

Nand.

Thanks Nand! I'm gonna try this out soon. I'll report back when I do it.

Nand... You da' Man! I've been wanting something like this to connect my CDM and Icom together (or anything else for that matter). No way in hell I was buying a R.I.C.K. for just playing around. I'm sure I can find a couple hundred uses for this around the firehouse too.

Only thing I'm a little lost on is the PL Hook Jumper. What is that? Maybe it is something I already know and just never heard it worded that way?

Matt,
Motorola sells a "plug" that plugs into the mic jack to jumper the mic hook circuit together when you don't have a mic plugged into the radio. Most commonly used for a "RICK" created repeater that doesn't have mic's plugged into it.

Haydn

Oh, ok. So this is what makes it think the mic is "on-hook" and doesn't go into monitor? Can't you just disable that feature in the RSS??

yes and yes

Perhaps the PL hook jumper should not have been drawn in the same diagram as the rest. It merely is the jumper plug that makes it look like the MIC is on hook when using PL with the repeater. If you use the rear accessory connector for the cable, you will need to use a MIC connector with a jumper between pins 3 and 4 and plug it in the RX radio. If you use the MIC connectors for the cable, you have to incorporate this jumper in the cable, but only if you plan to use PL at some time.

Suzan157 always suggest you permanently jumper the hook switch wires inside the radio. That is fine too, because you can always press the MON button if you need to check for other incoming signals without the correct PL.

And as Haydn says, you can do this with the RSS, but only in some Maxtrac radios. The radio wide screen in the Maxtrac has a setting for OffHookPL/DPL that needs to be flipped one way or the other.

I should mention that the first four people that looked at this diagram here downloaded a version with an error in it for the RX audio MIC pin number. That is corrected now.

http://www.storm.ca/~nand/990/RICK/rptr.pdf

Nand.

I split the diagram into two different pages, one for the 16 pin accessory connector and one for the MIC connector hookup. I also provided some information on where to find COR in radios without the 16-pin connector. If you like, you can mix and match!

http://www.storm.ca/~nand/990/RICK/rptr.pdf

Nand.

That is NEAT Nand! This gives me something to tinker with next weekend!


- Nick

Removed previous content.

I made an error here as HumHead pointed out below. You can use the same simple cable as above for CDM models instead.

Nand.

The jumper plug for the receiver radio's mic jack IS included with my Repeater Module as well as the timer/drop-out delay AND fail safe circuits.

Otherwise that (Nand's drawing) is the same simple circuit I forwarded to BatLabs a couple of years ago.

I can't get this link to work. Is it the right one?

http://66.46.218.199/990/rick/rptr.pdf

Nand:

Not to question someone who obviously has more experience and knowledge than myself, but are you certain about the lack of the bias voltage on the CDM accessory connector?

Here is why I ask:

On a project that I recently completed (finally), I had to split the audio output from a Zetron Model 38 to simultaneously feed both an MTR2000 and a CDM750. When I first fired up the system, I found that I was getting audio off of the CDM only. The MTR was transmitting PL only, no audio. When I unplugged / power off the CDM, The MTR2000 would pass TX audio.

To make a long story short, I put a scope on the CDM750 and found what looked a lot like a DC bias voltage, switched with radio power, on the mic input pin that was screwing up the op-amp on the MTR2000 interface board.

I installed a blocking capacitor on the input of the CDM750, and now all is well.

Am I missing / misunderstanding something here?

Thanks!

I am on vacation, but will be back this week. The http://www.storm.ca/~nand/990/RICK/rptr.pdf link should work. The other ones are off because at the last moment, I didn't like to take the lightning risk. The content is the same.

As far as no DC, I was very sure about this when I looked for it, but will post the relevant diagram areas when I get back.

I am working from a public computer here that uses a track ball and two buttons like a arcade game.

Nand.

HumHead wrote:Nand:

…. but are you certain about the lack of the bias voltage on the CDM accessory connector?

You are correct HumHead. The bias voltage is present on both the front and rear mic connectors. I originally looked at the PDF files for the CDM radios and saw exactly what I wanted to see. When I looked at the actual diagrams in the manual, I noticed my mistake.
Thanks for the info; I will remove the cable for the CDM since it now is pointless. The ones I built at the time did have a capacitor and the variable resistor in them.

Nand.

Hello Everyone,

I'm just curious, But has anyone tried this application out and can you share your findings with everyone. I'm thinking of trying this out with a pair of GM300's

Thanks

Nand wrote:http://www.domtoren.com/990/RICK/rptr.pdf

The above link is for a simple “RICK” interface that nearly anyone can build for under $10.00. It has excellent audio if properly adjusted. Actually, it can be adjusted to “taste” if you like. Keep the wiring less than 12 inches if possible. Shielded wire generally is not needed.

Nand.

I have now built up 6 or so of these units for use on a recent Professional Cycling race here in Australia.

I used 5 as standard repeaters and made up a set of 2 to make a really great Crossband Bi-directional repeater

All used either Gm300's or M120's and they worked like a dream for me

Thanks for the head's up on these in the first place Nand they work a treat.

For what it's worth, we ran them all at 5 watts and they didn't miss a beat

Thanks again for a simple circuit that works like a really complex one !

Regards
mike

Thanks mrtor,

That's All I needed to hear.

Have a Great Weekend.

Nand amd Group,

The diagram shows a 2.2uf cap that is polaruty sensitive. Is there anyway to use a 2.2u cap that is non polarized. I can not find a 2.2uf cap that is polarized anywhere around here. Is there another value cap I can use in it place??? Thanks for the help.
Kyle

You can easily use any capacitor from 1 to 10 uF, either polarized or not. Polarized (electrolytic) capacitors are physically smaller than their non-polarized counter parts, that is the reason for using these. The variable resistor is not critical either. Use anything from 2K to 10K and you should be fine. The 1.5 K resistor can be omitted if you like.

The values used in the diagram are identical to the parts used in the Motorola RICK but are not critical at all.


http://www.storm.ca/~nand/990/RICK/rptr.pdf

Nand.

Great, now if somebody can just tell me how to tune an 800 Maxtrac receiver down to something around 815.xxx, I could take this pile of maxtracs I have here and make something useful out of them!

None of the links are working...anyone have this? I printed it,but can't find it now that I need it!
mod

None of the links are working...anyone have this?

Ditto... I would love to have a copy.

I have it on my desktop.. but it ain't working right now. Once it's up I'll post them. No ETA on that though, short on $$ right now.

http://69.156.220.119/990/RICK/rptr.pdf

just worked for me.

Thanks Nand for fixing the link

Simple, BUT you forgot the GROUND lead between the two radios.

Only problem here is if the receiver radios looses power or fails, the transmit radio keys up forever!!!!

Question...

Have a VHF CDM1250 mounted in cars dash. Can I use the above mentioned RICK to connect a UHF GM300 (mounted in trunk) and connect it to the VHF CDM 1250 for crossband operation. All while still being able to use the dash mounted VHF CDM 1250 in normal non repeater mode when needed.

I plan on using the 16 pin connector on the CDM 1250, and the mic socket on the GM300.

Would there be a way to enable/disable the crossband operation with the VHF CDM1250?

Thanks guys

No, that circuit is for a simple one way repeater. you would have to build two of those circuits and the cables to go inbetween the radios. There are serious ground loop problems with that circuit, and it does not have any failsafe protection in it.

What you need is a Extender Module for a remote mount radio.

see http://www.webimaging.com/echocomm/

Will wrote:Simple, BUT you forgot the GROUND lead between the two radios.

Only problem here is if the receiver radios looses power or fails, the transmit radio keys up forever!!!!

Will wrote:No, that circuit is for a simple one way repeater. you would have to build two of those circuits and the cables to go inbetween the radios. There are serious ground loop problems with that circuit, and it does not have any failsafe protection in it.

Ground loop problems???

The additional ground wire between the two connectors (pin-7) is intentionally not there. Since the two radios both have their power wiring connected to the same source with fairly heavy wire that has a low resistance and low impedance for the audio signals involved, the two radios can be considered as sitting on the same chassis even though they are not.

Adding a ground wire between the two accessory connector grounds (pin-7) actually could cause damage if the TX radio ever lost it’s main power ground and started drawing current through the signaling ground wire from the RX radio instead. This actually is a possibility with the real Motorola RICK if doing sloppy work.

To be really safe, both radio frames should be bonded together, either with a strap or through a metal cabinet with the proper mounting brackets.

As for the TX radio staying keyed when the RX radio fails or is turned off, that is what the timeout timer in the TX radio programming is for. It prevents the TX radio from staying keyed the same way it would as if somebody shoved the mic between the car seats with the PTT button pressed in.

It is true when some RX radio models when turned off cause the TX radio to transmit. Both the 2 and 8 channel GM300 model will not cause this problem because both of these use an open collector output transistor for COR on pin-8.

Also, the likelihood of the RX radio failing is about the same as the likelihood that an external controller fails and causing an identical problem. The built in time out timer prevents all the above problems and is required by regulation. And if for some reason it is needed that the TX radio gets disabled when the RX radio is turned off, then wire the RX radio’s switched B+ pin to the TX radio’s ignition control line and remove the TX radio's internal fuse. Now the TX radio will turn off when the RX radio is turned off or DC power.

Others and I built repeaters based on this simple diagram in both one-way and bi-directional cross band configurations without any problems.

Nand.

Will wrote:No, that circuit is for a simple one way repeater. you would have to build two of those circuits and the cables to go inbetween the radios. There are serious ground loop problems with that circuit, and it does not have any failsafe protection in it.

What you need is a Extender Module for a remote mount radio.

see http://www.webimaging.com/echocomm/

Ya, that sounds like the better choice - thanks for the link Will

This is a project for the spring - I can't wait

This link is down! please do something nand...

Nand wrote:http://www.domtoren.com/990/RICK/rptr.pdf

The above link is for a simple “RICK” interface that nearly anyone can build for under $10.00. It has excellent audio if properly adjusted. Actually, it can be adjusted to “taste” if you like. Keep the wiring less than 12 inches if possible. Shielded wire generally is not needed.

Nand.

Hello zahidan :

I just accessed the link at the top of the page and it went through just fine for me.

If you need it opened and forwarded by email = id be happy to do it for you.

Just drop me a PM with your email address and ill email the info from the site.

EKLB

http://www.domtoren.com/990/RICK/rptr.pdf

http://www.storm.ca/~nand/990/RICK/rptr.pdf

All the above links work.

Nand.

Thanks EKLB

Nand.

Hi Nand. Good to see you back.

I'm willing to bet that anything produced by echocomm will cost you a bit more that $10 an a little of your time.


Nand, thanks for posting this.

Yes by using used component we can still make it work. Less than USD5 thank to NAND for the idea.

Thank you ELKB for offering me a support. I already managed to get it somehow but this site http://www.domtoren.com/990/RICK/rptr.pdf still down.