Quick question about Input and Output frequencies

[LSD4me]

Just a quick ?.....I noticed that by each frequency, there is an INPUT freq listed. WHAT IS THIS FOR? DO i need to monitor this as well as the 1st freq?

500.61250 503.61250 BR 364 Springfield Twp secondary FM

I have programmed 500.6125 in the scanner. Should i also program 503.6125? What is this for? ANy help will be appreciated!!

Also, if you know what TYPE BR, BM or M or no what the TONE is for, can you explain as well... THANKS ALOT!!!!!!

 

[grem467]

its the frequencies the radios use to access the repeater, you dont need to program those in to a scanner, unless you want to hear them when they are extremely close to you.

 

[scannerfreak]

Just a quick ?.....I noticed that by each frequency, there is an INPUT freq listed. WHAT IS THIS FOR? DO i need to monitor this as well as the 1st freq?

500.61250 503.61250 BR 364 Springfield Twp secondary FM

I have programmed 500.6125 in the scanner. Should i also program 503.6125? What is this for? ANy help will be appreciated!!

Also, if you know what TYPE BR, BM or M or no what the TONE is for, can you explain as well... THANKS ALOT!!!!!!

BR= Base Repeater

B=Base

M=Mobile

BM=Base/Mobile

R=Repeater

F=Fixed

The tone, PL-Private Line and DPL-Digital Private Line, are used to keep other users of the same frequency from being able to hear each other...

 

[SAR923]

Input frequencies are used to activate the repeater. You always want to have the output frequencies programmed since that way you'll hear both sides of the conversation.

There are systems that that do use the input frequency for a "talk around", or car to car frequency. If you happen to be close enough to the units transmitting, you can hear some interesting things.

 

[nmfire10]

I've heard of very very very few instances of using the INPUTS for talk-around. It's very stupid. Usually, talk-around is on the output.

 

[LSD4me]

Would it hurt to program both INPUT and OUTPUT? Seems like both would be better....

 

[jastx]

To hear both sides of a conversation, I normally have just the output with a delay set in the scanner. Monitoring the input with a delay could cause you to miss some of the conversation. But adding the inputs without a delay won't damage your radio. Try it. If you don't like it, you can change it. I've found my scanner program improves over time as I learn.

 

[SAR923]

I've heard of very very very few instances of using the INPUTS for talk-around. It's very stupid. Usually, talk-around is on the output.

I don't recall saying this was common. However, systems can and do use input frequencies for talk around purposes. It's not stupid. Our system has the ability to use either the output or input frequencies for talkaround. Since almost no one has input frequencies in their scanners, it's a good frequency for close-in, car to car communications that are less likely to monitored by the press, for example.

 

[nmfire10]

And I don't recall saying that you DID say it was common. I was simply stating how it is rare and dumb. Using the input with a different or no PL will accomplish nothing but interfere with someone who is trying to use the repeater as normal. They have no way of knowing that someone is talking on the input and you will end up with a bunch of garbled crap. If it is on the output like most everyone else, the other mobile and portable units can still hear it within a reasonable range.

 

[SAR923]

And if you've ever tried to talkaround on an output frequency, you'll know how frustrating it is when you're constantly being covered by other output traffic. Our system uses no PL for talkaround on input and our radios drop to two watts for input talkaround. It doesn't cause any "garbled crap" since the input freqency isn't even picking up the traffic. I agree that it's rare but our comms director would not agree it's "dumb". Of course, he only has 25 years experience setting up radio systems. You may be better qualified than he is to make such judgements.

 

[OpSec]

Yes, you have to contend with repeated audio using the output as the T/A channel. However, you should only be using it when in the immediate area of the other car(s) and therefore the receiver -should- capture the T/A traffic over the repeater. Yes, I know this is not always the case.

The problem with using the input is once a car on F1 with PL keys up, the system can hear your radio on the input without PL, since the repeater has already been keyed by the radio transmitting PL...this opens up the possibility of the system receivers hearing both radios and allowing them to cover each other.

Using the input as a T/A is rare and 25 years experience or not, it is still a bad idea.

 

[Voyager]

The problem with using the input is once a car on F1 with PL keys up, the the system then can hear your radio on F2 without PL, since the repeater has already been keyed by the radio trasmitting PL...this opens up the possibility of the system receivers hearing both radios and allowing them to cover each other.

Not quite. Due to capture effect, one of the two radios will be 'heard' by the repeater receiver. If it's the one with PL, the repeater will activate and pass the audio of that mobile. If the non-PL'ed mobile (or portable) is stronger, the repeater will never see the PL and will not activate - period. If the repeater sees the PL mobile, then the non-PL mobile becomes stronger, the RX will mute and the repeater won't pass any audio (or shouldn't - some repeaters are CSQ audio and PL COS which is the wrong way to set them up).

Granted, capture effect isn't absolute, but if the signal is strong enough for the repeater to see the PL, it is strong enough to hear the audio on the PL'ed transmitter.

Joe M.

 

[OpSec]

The problem with using the input is once a car on F1 with PL keys up, the the system then can hear your radio on F2 without PL, since the repeater has already been keyed by the radio trasmitting PL...this opens up the possibility of the system receivers hearing both radios and allowing them to cover each other.

Not quite. Due to capture effect, one of the two radios will be 'heard' by the repeater receiver. If it's the one with PL, the repeater will activate and pass the audio of that mobile. If the non-PL'ed mobile (or portable) is stronger, the repeater will never see the PL and will not activate - period. If the repeater sees the PL mobile, then the non-PL mobile becomes stronger, the RX will mute and the repeater won't pass any audio (or shouldn't - some repeaters are CSQ audio and PL COS which is the wrong way to set them up).

Granted, capture effect isn't absolute, but if the signal is strong enough for the repeater to see the PL, it is strong enough to hear the audio on the PL'ed transmitter.

Joe M.

Re-reading my post, I left out info that I shouldn't have. It is:

If the situation is one that if radio "A" with PL on F1 is keyed up, and a radio "B" without PL keys up on F2 during the middle of A's transmission and captures the receiver, then it will cover A's transmission and drop the repeater unknown to the user of A...which is not good and poses an officer safety issue.

In my post, I made it rather vague...my apologies. You did mention it though.

Also, I realize that if the F2 radio doesn't have a PL, it won't key the repeater....but it does create nuisance issues like above with F1 traffic if it's non PL signal is strong enough.

some repeaters are CSQ audio and PL COS which is the wrong way to set them up

Been there, seen that...in both ham and public safety. They wondered why it was so easy to interfere with them, even though the suspect radio was not transmitting PL :roll:

Regardless, it is still better to use the output for a T/A channel...less chances of interference or missed info due to the problem mentioned above.

 

[nmfire10]

And if you've ever tried to talkaround on an output frequency, you'll know how frustrating it is when you're constantly being covered by other output traffic. Our system uses no PL for talkaround on input and our radios drop to two watts for input talkaround. It doesn't cause any "garbled crap" since the input freqency isn't even picking up the traffic. I agree that it's rare but our comms director would not agree it's "dumb". Of course, he only has 25 years experience setting up radio systems. You may be better qualified than he is to make such judgements.

Well you must have one of those "magic" radio systems that allow more than one radio transmit on a frequency at the same time and not cause interference. :roll: If someone is talking on the input CSQ, somone keying up to use the repeater will have no clue that is taking place. The result will be two untis at once on the input.

The "capture effect" may not happen at all if they are both close to the same strength which is highly probably. In that case, they will mix. If the PL happens to not get distorted to much, it might even still open the repeater and pass the garbled crap. Regardless of capture or no capture, no one is going to understand either end of the conversation.

I don't give a rat's ass if your comm director is jesus christ. You don't need to be a rocket scientist to figure out why this is not a great idea. I've always looked at agencies that do this as "too cheap to license a seperate talk-around channel" rather than "really smart". :roll:

As far as getting stepped on by "output" traffic... you have a better chance on the output than the input. At least other mobile and portable units might be able to hear you and will not step on you. Dispatch will never be able to hear you on any talk-around mode unless you install receivers on them for dispatch to monitor.

 

[Voyager]

The problem with using the input is once a car on F1 with PL keys up, the the system then can hear your radio on F2 without PL, since the repeater has already been keyed by the radio trasmitting PL...this opens up the possibility of the system receivers hearing both radios and allowing them to cover each other.

Not quite. Due to capture effect, one of the two radios will be 'heard' by the repeater receiver. If it's the one with PL, the repeater will activate and pass the audio of that mobile. If the non-PL'ed mobile (or portable) is stronger, the repeater will never see the PL and will not activate - period. If the repeater sees the PL mobile, then the non-PL mobile becomes stronger, the RX will mute and the repeater won't pass any audio (or shouldn't - some repeaters are CSQ audio and PL COS which is the wrong way to set them up).

Granted, capture effect isn't absolute, but if the signal is strong enough for the repeater to see the PL, it is strong enough to hear the audio on the PL'ed transmitter.

Joe M.

Re-reading my post, I left out info that I shouldn't have. It is:

If the situation is one that if radio "A" with PL on F1 is keyed up, and a radio "B" without PL keys up on F2 during the middle of A's transmission and captures the receiver, then it will cover A's transmission and drop the repeater unknown to the user of A...which is not good and poses an officer safety issue.

In my post, I made it rather vague...my apologies. You did mention it though.

Also, I realize that if the F2 radio doesn't have a PL, it won't key the repeater....but it does create nuisance issues like above with F1 traffic if it's non PL signal is strong enough.

some repeaters are CSQ audio and PL COS which is the wrong way to set them up

Been there, seen that...in both ham and public safety. They wondered why it was so easy to interfere with them, even though the suspect radio was not transmitting PL :roll:

Regardless, it is still better to use the output for a T/A channel...less chances of interference or missed info due to the problem mentioned above.

Agreed 100%.

I've also seen cases where businesses were licensed for simplex on the input frequency of a repeater. They never seemed to receive interference from the repeater users, but certainly caused interference to the repeater users. Different PL - same result. They almost always captured the repeater RX since they were line-of-sight to the repeater and used 100W mobiles with gain antennas on the top of busses. They chose to use normal biz freqs rather than the frequencies specifically reserved for their type of operations. (shuttles at an airport)

Joe M.

 

[n4yek]

Can't we all just get along...

The man asked a simple question and thats it.
Arguing over who is right , wrong, or experts
of radio wave technology had nothing to do
with his question.

Program both freqs into your scanner and let the
two guys argue over this trivial matter of 'talk-around'.

Danny

 

[eyes00only]

Can't we all just get along...

I agree, but it's not a good idea to put the input freq. in, except for maybe an xperiment. If you heard someone say "switch to talkaround", give it a try. In my approx. 15 years in the hobby, I have never needed to monitor an input.

Jerry 8)

 

[Voyager]

Can't we all just get along...

The man asked a simple question and thats it.
Arguing over who is right , wrong, or experts
of radio wave technology had nothing to do
with his question.

Program both freqs into your scanner and let the
two guys argue over this trivial matter of 'talk-around'.

Danny

Yep. Question was asked. Question was answered. Related discussion ensued. What seems to me to be trivial is complaints about the discussion. I mean, it's not like you are being forced to continue to follow the thread. If someone wants to take the topic and put some finer points on it, what's the big deal? I don't know of anyone who knows everything about radio. Some of us want to continue to learn, and discussing points like these is a great way to do that.

If the thread offends you that much, DON'T READ IT. If you already know everything and don't wish to participate in the discussion, DON'T READ IT. I hope my hints came through well.

There are some valid points for talkaround on the input (mostly privacy), but there are also valid points for NOT having TA on the input (mostly officer safety and interference concerns). Please don't try to stiffle the learning process for everyone else.

By the way, there are four of us discussing the pros and cons of using inputs for talkaround, and I think the discussion has been pretty civil. (until your post)

Joe M.

 

[INDY72]

OK here is a simple answer,... for a Lo Band set up,.. sure put both in, for Hi Band, UHF, and 800/900, Its just so much simpler to go with the outputs only,... But you can go ahead and run the inputs to see just how it will work,... If your scanner is PL/DPL capable, remember to put the outputs with proper PL/DPL in one chan, and then again in a seperate chan, and inputs in another chan.....this way you will get the difference if talkaround is used on iether one.

 

[Voyager]

OK here is a simple answer,... for a Lo Band set up,.. sure put both in, for Hi Band, UHF, and 800/900, Its just so much simpler to go with the outputs only,... But you can go ahead and run the inputs to see just how it will work,... If your scanner is PL/DPL capable, remember to put the outputs with proper PL/DPL in one chan, and then again in a seperate chan, and inputs in another chan.....this way you will get the difference if talkaround is used on iether one.

Since you're going to have the input and output in CSQ anyway for possible TA use, why bother putting the repeater in with the correct PL/DPL? Seems a waste of a channel. Just asking.

One use that I don't think has been mentioned yet is that you can guage how close a unit is to you if you have the input in. If you are going to put the input and output in your scanner, be sure to put the input in FIRST, THEN the output or your scanner will always stop on the output. Of course, if your area uses TA on the input without PL/DPL, and this is your only concern, reverse the order. That way, you will hear everything, and only hear the input TA if they are using it. (or they start talking JUST after your scanner passed the output frequency, but not the input.

On GRE scanners, take scan direction into account, too.

Joe M.