CB isue i have

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followspot2

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Hi all thanks for all the help so far.

* the next but i talk about is illegal what I did should you should not do what I have done!

So I got my hands on 2 UHF CB radios which i liked to together, with the speaker out of one into the microphone in on the other. one being on CB 25 and the other being on CB 28. Also other information about the radios is that they were operating at 7W and had bigger antennas put on them. I them gave it a test while it was all in front of me, where it worked perfectly. After that I took this repeater and some rope and took it to the high spot that i has selected from http://link.ubnt.com (yes i know it is not the best but it worked for finding the high spot)

I then strung the repeater up in a tree, and gave it a test where it was still working correctly. so i then wend to the station where i knew i needed to get coverage to, and gave it a test there where it worked. so then i went on my route home where i tested it all the way. but i ran into a huge issue, there a building in the way and my single would drop to nothing and i would only about 500m from the repeater. so then i tryed moving the repeater to new place with no better luck i move it 8 times. there was only one place i did not move it to which was the phone tower at the top of the hill, because 1 i had nowhere to put it into a tree, and 2 i did not want to cause any interference.

So what i have come to now is that it was a lost cause, and that i am giving up.

Thanks for every ones help and it was greatly appropriated, and i learnt a lot.
 

RFI-EMI-GUY

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Hi all thanks for all the help so far.

* the next but i talk about is illegal what I did should you should not do what I have done!

So I got my hands on 2 UHF CB radios which i liked to together, with the speaker out of one into the microphone in on the other. one being on CB 25 and the other being on CB 28. Also other information about the radios is that they were operating at 7W and had bigger antennas put on them. I them gave it a test while it was all in front of me, where it worked perfectly. After that I took this repeater and some rope and took it to the high spot that i has selected from http://link.ubnt.com (yes i know it is not the best but it worked for finding the high spot)

I then strung the repeater up in a tree, and gave it a test where it was still working correctly. so i then wend to the station where i knew i needed to get coverage to, and gave it a test there where it worked. so then i went on my route home where i tested it all the way. but i ran into a huge issue, there a building in the way and my single would drop to nothing and i would only about 500m from the repeater. so then i tryed moving the repeater to new place with no better luck i move it 8 times. there was only one place i did not move it to which was the phone tower at the top of the hill, because 1 i had nowhere to put it into a tree, and 2 i did not want to cause any interference.

So what i have come to now is that it was a lost cause, and that i am giving up.

Thanks for every ones help and it was greatly appropriated, and i learnt a lot.
I think it still has merit and the rules do not specifically prohibit linking stations in this way.

You might try using channels that are further apart, say 750 KHz if possible. Or channels 12 or 39 more practical. You are probably getting desense from the TX antenna being so close to the receive antenna.

For a fixed installation I would recommend YAGI or corner reflector antennas.
 

RFI-EMI-GUY

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Yes they do.

R
Show me the specific rule prohibiting this.

Also the new rules had prohibition on linking removed and the ACMA webpage states such relaxation if rules. This is linking via remote base, not a repeater.


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RFI-EMI-GUY

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A careful read of this document reveals they have removed the prohibition on linking CB channels. Instead should there be interference they will use enforcement tools to curb it. See discussion on page 5.

The change is outlined in Page 7, see second bullet:

"Considering this, the ACMA is proposing to:
> remove paragraph 5(1)(b) of the 2015 CBRS Class Licence, having the effect of permitting the continued use of wideband equipment after 30 June 2017
> remove paragraph 6(i) of the CBRS Class Licence, which provides that CB stations must not be used to link CB repeaters or CB channels."


https://www.acma.gov.au/Home/Citize...~/media/F969D7801E61473DBC5A571F6A6D524C.ashx

My read is that if you do this without causing interference (Use CTCSS on the link) they will not bother you. If you do cause interference they will ask you to shut it down and may take action if you don't. If you do it, do it carefully and make sure it does not bother anyone on the channel chosen for the link. As far as "non standard transmitter" under the act. If you can make the link without modification of the radios you should be fine.

Getting COR from each radio might require shopping for a radio that either gives you a COR directly from an option pin or where you can derive COR from an unsquelch indicator lamp/photo cell arrangement or from DC voltage change on the speaker leads. Otherwise you could use VOX but that sucks. None of this is impossible, just takes care in the design. To be honest, running a COR wire from the receiver of each radio out the back panel does not seem to be a very substantial modification to the radio and doing such in itself would not normally cause interference. If the radios have a time out timer, by all means engage it.

There are a lot of commercial controllers that can interface and set levels, and provide remote DTMF control, but you need one for remote base. Otherwise this can be done with a couple relays or opto-isolators for COR/PTT level translation and resistors to match speaker levels to mike input levels. A caveman can do it.
 
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RFI-EMI-GUY

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Thanks for the update on this, sorry it didn't work out for you.
I don't know what happened to the OP. But he was testing with two channels only 75KHz away from each other. It will never work that way without a TX desensing an RX. Legality isn't an issue as the rules were relaxed in 2017 to permit linking of channels.
 

GregW67

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I have been able to receive 5 watt simplex UHF transmissions (railway, business) at distances in the 5-10 km range with fairly large hills in the way simply by using a very low noise preamp and a high-gain collinear antenna - and in some cases even just using a very low-noise preamp in my car with a 4.5 dBi mobile antenna. If reception of 5 watt transmissions in this distance range is possible, then wouldn't two-way communications also be possible, as long as both parties used this type of equipment for the receive part? Regarding the 100 metre hill in the way, yes that's a major obstacle but it may still be possible if both parties used either a tilted or angled-beam collinear or a Yagi aimed at the top of the hill.
 

RFI-EMI-GUY

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That would seem to be sort of a best case scenario. Not practical for this one guy trying to participate with an established group that likely is mobile.
I have been able to receive 5 watt simplex UHF transmissions (railway, business) at distances in the 5-10 km range with fairly large hills in the way simply by using a very low noise preamp and a high-gain collinear antenna - and in some cases even just using a very low-noise preamp in my car with a 4.5 dBi mobile antenna. If reception of 5 watt transmissions in this distance range is possible, then wouldn't two-way communications also be possible, as long as both parties used this type of equipment for the receive part? Regarding the 100 metre hill in the way, yes that's a major obstacle but it may still be possible if both parties used either a tilted or angled-beam collinear or a Yagi aimed at the top of the hill.
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GregW67

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That would seem to be sort of a best case scenario. Not practical for this one guy trying to participate with an established group that likely is mobile.

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Sorry, I had not read the posts thoroughly. I had assumed he wanted to talk to one fixed operator. I agree that talking to a group that is likely mobile would make it much harder - at the very least he would experience deep fading and dropping out of the signal.
 

followspot2

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Just for a update. I have now found a solution for my issue. I will not be explaining how i did it in case someone from the ACMA is reading this. All i am willing to say is that it is a very janky solution, and when i say very i mean very.

Thanks for all the support that you game me.

RFI-EMI-GUY you're page which you found seems to be a propose and that there is nowhere where it says that it leagel.
 

RFI-EMI-GUY

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Just for a update. I have now found a solution for my issue. I will not be explaining how i did it in case someone from the ACMA is reading this. All i am willing to say is that it is a very janky solution, and when i say very i mean very.

Thanks for all the support that you game me.

RFI-EMI-GUY you're page which you found seems to be a propose and that there is nowhere where it says that it leagel.
The new ACMA rules reflect the deletion of that prohibition that is described in the proposal which was apparently adopted .

PM me about your JANKY solution. I am in the US. Just trying to help, have no legal interest in that ACMA.




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