Another TX916/RX916 question.

[tcs-5]

I was thinking of adding a wirless link between my SG7 microwave oscillator output and the counter unit. Can the TX916/RX916 units serve this purpose?

John

[Ramsey Tech Z99]

No, the microwave oscillator board is sending audio to display board. The TX/RX units transmit data. The wireless link you use must be able to transmit and receive audio. You also will need to find a way to power the microwave board since it normally receives its power from the Display Board via the interface cable.

[tcs-5]

Z99,
Do you have any suggestions for a TX/RX to use with my SG7? I looked in the Ramsey Catalog that would suit the purpose.
As for powering the oscillator, I figured on using Lithium Polymer cells. They have the highest current density available.

John

[Mark W]

John,
We used to have a little policy of "if you have to ask, it can't be done!" , but this is interesting. The audio the tech is speaking of is actually pulses which are a result of the mixing of outbound microwaves vs. incomming. The counter unit counts these pulses.

However the pulses coming out of the unit are quite small in amplitude and need to be amplified, which is done in the counter unit. If you wanted to send these pulses via the wireless link, you would have to boost the pulses to TTL levels (0 and 5V) first before sending to the TX. Then on the RX end, you shouldn't need to knock the level back down. You will also need to power the hand-held unit seperatly.

I can't really tell you how to hack the kit up, but remember you will be voiding the warranty.

-Mark W.

[tcs-5]

Mark,
Thanks for your reply.

I'm sure you have those asking to do things that are beyound their and the kits ability. This is not the case here. I just thought there might be a nice little low power TX/RX package that would work here.

Also the idea is not to "hack" the SG7 kit but to use as designed while eliminating the cable. The RF link would be invisible to the SG7, in that it would function the same with the cable or with the RF link. Either one could be used.

Yes, you are correct that the few milliwatts of doppler hetrodyne audio would not be enough for some RF TX inputs to modulate so some preamplification would be needed. I thought of useing the Relm or Standard TX/RX link modules. They have preamplified inputs on the TX module as well as dual conversion RX modules. AT aprox 2 watts and $100 for just the TX unit, it seemed a wee bit out of line for a $59.00 radar gun kit. Overpowered and over priced!

I will do a little more research for a suitable low cost TX/RX link and if one is found would be happy to post the results here, if working of coarse. I will not post a competitors unit unless I had the approval of the Ramsey Co.

Thanks again,
John

[Mark W]

We have TX/RX wireless links that would work for your purpose. TX433... Take a look!

[tcs-5]

Wait a minunte, did I miss something? If the TX916 woun't work for my project why would the TX433. Arn't they basicly the same only on different freqs.? Please explain.

John

[Ramsey Tech Z99]

The output of the oscillator board is a low level Sine Wave from zero to 800 Hz depending on the speed of the object being tracked (frequency = 7.76 * MPH).

You could use the TX/RX unit if you amplified and shaped the wave as Mark W. suggested. This will require you designing and building your own circuit.

Another option would be to find an audio transmitter and receiver system. You will want to make sure that any system will be able to handle the low-end frequencies near zero hertz. This will limit the low speed response of your SG7. You may consider the MR6 as the transmitter and a scanner for a receiver. I am not sure about the low-end frequency limits of the MR6. We have never tested it for an application like yours.