Radio Transmission Delay on Radio to Smart Device

[lrdchivalry]

I have a question and would like to see if anyone has any answers or suggestions. My work uses these tiny little hand held radios, the volume sucks and I have a hard time hearing it in noisy environments. Some employees use a smart phone like device that has a walkie talkie feature that will transmit to the little radios and receive from them as well. With permission I started using my own radio. Had the freqs and correct privacy tones programmed into it. The problem is with the smart phone type device. I can receive transmissions from this device instantly, however, when I transmit, I have to key the mic between 6-10 seconds before the smart phone type device will open up and someone can here me. It does not do that with the little radios and I do not have that problem talking with the little hand held radios. Anyone have an idea what the problem might be and how to fix it? Thanks!

 

Respectfully,

D

[WRAK968]

To better help you we would need to know the make and model of radio you are using. To me it sounds like you are using a split network/conventional radio, which I am not sure there are any that are part 90 accepted (required for commercial radios)

 

Depending on how its transmitting, either via VHF/UHF signal, or through the cell network, will dictate any delays. It is common for cell network connections to take a little time to connect to the base radio and be transmitted, poor signals and poor internet connections to the base radio will further extend said delay.

[rdunajewski]

This could be one of several issues. Sounds like they're using a gateway to take the RF radios and send the audio to an app like Zello running on network radios (the smartphone style) as a bridging of two systems. Zello is known to have audio delays because the audio is sent to the server first, then it's delivered to the client (app) once it's able to. This way if you lose network connectivity, once you get it back you'll still get the message (you didn't miss it). So there's always a little delay there based on the network. They guarantee delivery but not real-time communication. This is a problem with bridging busy networks because the RF side could be replying but now Zello is behind the game and trying to step on the RF traffic. We have the same issue with Zello users on our myGMRS Network, nets are especially problematic.

 

However, it could be that there's something on the RF or gateway side that isn't detecting your signal for a while (although 10 seconds is way too long, so I doubt that). Some repeaters for instance take a while to decode your PL tone, begin transmitting, and start passing the audio. But this is usually a second or less.

 

Any info you can pass along on the types of radios or the app can help us figure out where this delay could be coming from.

[lrdchivalry]

This could be one of several issues. Sounds like they're using a gateway to take the RF radios and send the audio to an app like Zello running on network radios (the smartphone style) as a bridging of two systems. Zello is known to have audio delays because the audio is sent to the server first, then it's delivered to the client (app) once it's able to. This way if you lose network connectivity, once you get it back you'll still get the message (you didn't miss it). So there's always a little delay there based on the network. They guarantee delivery but not real-time communication. This is a problem with bridging busy networks because the RF side could be replying but now Zello is behind the game and trying to step on the RF traffic. We have the same issue with Zello users on our myGMRS Network, nets are especially problematic.

 

However, it could be that there's something on the RF or gateway side that isn't detecting your signal for a while (although 10 seconds is way too long, so I doubt that). Some repeaters for instance take a while to decode your PL tone, begin transmitting, and start passing the audio. But this is usually a second or less.

 

Any info you can pass along on the types of radios or the app can help us figure out where this delay could be coming

.

 

The small radios are from Advanced Wireless Communications and is either their AWR Advantage or AWR Advantage Plus model. Funny, this delay does not happen when using the Advanced Wireless radios. The smart device is the Zebra Industries TC77. As for the app used, I would have to look and see if it shows it. 

[lrdchivalry]

To better help you we would need to know the make and model of radio you are using. To me it sounds like you are using a split network/conventional radio, which I am not sure there are any that are part 90 accepted (required for commercial radios)

 

Depending on how its transmitting, either via VHF/UHF signal, or through the cell network, will dictate any delays. It is common for cell network connections to take a little time to connect to the base radio and be transmitted, poor signals and poor internet connections to the base radio will further extend said delay.

 

I am using an Ailunce HD1. My employer is using UHF frequencies and DPL's.

[JLeikhim]

I am using an Ailunce HD1. My employer is using UHF frequencies and DPL's.

If your modulation is weak, the radio to IP gateway may be slow to respond to your voice. Also there could be a problem with your DPL being decoded reliably. Have you compared performance with a company issued radio?

 

Sent from my SM-T350 using Tapatalk

[lrdchivalry]

If your modulation is weak, the radio to IP gateway may be slow to respond to your voice. Also there could be a problem with your DPL being decoded reliably. Have you compared performance with a company issued radio?

 

Sent from my SM-T350 using Tapatalk

 

The company radios work fine with no delays. Could it be a power issue, I have it set on low (1 watt)? I am not sure what transmission power level the company radios are transmitting at.

[JLeikhim]

Do the company radios transmit any preamble tones like MDC1200?

 

No the power level should not make much difference.

 

Sent from my SM-T350 using Tapatalk

[Radioguy7268]

Chances are that the device is having trouble decoding your particular DPL, as generated by your radio. 

[lrdchivalry]

Do the company radios transmit any preamble tones like MDC1200?

 

No the power level should not make much difference.

 

Sent from my SM-T350 using Tapatalk

 

I have no idea, not being radio savvy I had to look up MDC 1200. I didn't see anything in the specs for the radios that mention MDC 1200.

[lrdchivalry]

Chances are that the device is having trouble decoding your particular DPL, as generated by your radio. 

 

If that is the case, what would be the solution? I am using the the correct DPL.

[Radioguy7268]

If that is the case, what would be the solution? I am using the the correct DPL.

 

Simplest solution would be to just try a different radio (prefer a Part 90 type accepted radio of proven design/performance) and program in the same frequency/code combination.

 

Beyond that, you could put your current radio on a Service Monitor & see how well it's actually performing, ie: How stable is it? How well does it hold the programmed center frequency - what's the amount of drift? What's the deviation level and stability of the DPL? What's the total deviation?

 

When you programmed your radio - did you set it for narrowband 12.5 kHz?  Pretty much any UHF business band frequency would be a 12.5 emissions mask.

[lrdchivalry]

Simplest solution would be to just try a different radio (prefer a Part 90 type accepted radio of proven design/performance) and program in the same frequency/code combination.

 

Beyond that, you could put your current radio on a Service Monitor & see how well it's actually performing, ie: How stable is it? How well does it hold the programmed center frequency - what's the amount of drift? What's the deviation level and stability of the DPL? What's the total deviation?

 

When you programmed your radio - did you set it for narrowband 12.5 kHz?  Pretty much any UHF business band frequency would be a 12.5 emissions mask.

 

 

I do have a AT AT-D878UV I could try. I did notice that the bandwidth on the HD1 was set at 25. I changed it to 12.5. I have carried issued radios in a previous job but when it comes to the the behind the scenes operations of radios I am pretty clueless. Hopefully I can get this issue figured out since the work radios are junk and I am allowed to carry my own if I can get the issue fixed.

[JLeikhim]

Have you tried talking to and from a company issue radio? Is there any delay in that mode?

 

This is a common problem with cheap Chinese radios. Users cannot get them to work reliably with other radios or repeaters. They may be totally out of tune or have a defect because they are not engineered to the standards that more expensive radios are.

 

Then we have the programming using "Chirp" software which is intended for ham radio operators, who may or may not have technical savvy to sort out the potential problems. If they cannot, its not a problem because they are playing in the ham radio "sand box" not a business or public safety environment (hopefully).

 

Frankly I am surprised your employer is letting you use your own radio on the job. Your company selected a vendor, that admittedly is offering some pretty low end stuff, but it is perhaps well sorted out by their technicians before putting into service.

 

How did you get the frequencies and DPL? Did your employer hand you the information or did you monitor it off the air? If off the air you may have frequencies transposed or erroneous, the DPL may be the wrong one because cheap radios respond with multiple solutions, two or three of which are probably wrong.

[lrdchivalry]

Have you tried talking to and from a company issue radio? Is there any delay in that mode?

 

This is a common problem with cheap Chinese radios. Users cannot get them to work reliably with other radios or repeaters. They may be totally out of tune or have a defect because they are not engineered to the standards that more expensive radios are.

 

Then we have the programming using "Chirp" software which is intended for ham radio operators, who may or may not have technical savvy to sort out the potential problems. If they cannot, its not a problem because they are playing in the ham radio "sand box" not a business or public safety environment (hopefully).

 

Frankly I am surprised your employer is letting you use your own radio on the job. Your company selected a vendor, that admittedly is offering some pretty low end stuff, but it is perhaps well sorted out by their technicians before putting into service.

 

The company radios do not have this issue. I am not sure what constitutes a cheap Chinese radio, I paid about $189 for the HD1, which is a lot for me and never had an issue reaching a repeater or radio until now. My supervisor and managers had no issue with it, however, I had to go back to using a company radio while trying to figure this issue out.

[Radioguy7268]

Back up to the issue that WPXM352 brought up - how did you get the Frequency and Code?

 

There are certain PL codes that can "false" as a DPL - and if you read the DPL off the air with your radio, it's possible that you're close, but not quite there. The idea that it's taking so long for your Gateway device to recognize your particular radio as a Valid User indicates that there's something not quite right with the way your radio is presenting itself.

 

I hate to say, but there's also shops within the industry that will NOT give out PL tones correctly if a customer calls in looking for system information.

[lrdchivalry]

Back up to the issue that WPXM352 brought up - how did you get the Frequency and Code?

 

There are certain PL codes that can "false" as a DPL - and if you read the DPL off the air with your radio, it's possible that you're close, but not quite there. The idea that it's taking so long for your Gateway device to recognize your particular radio as a Valid User indicates that there's something not quite right with the way your radio is presenting itself.

 

I hate to say, but there's also shops within the industry that will NOT give out PL tones correctly if a customer calls in looking for system information.

 

I got the freqs from the fcc website and the DPL tones off of radio reference since management had no clue what I was talking about when I mentioned freqs and DPL's. If the DPL was off or wrong wouldn't my radio's squelch not open up? If my radio is not a valid user would I still be able to receive transmissions from the smart devices or even the company radios since they all use the same gateway? If it doesn't recognize my radio I shouldn't be able to transmit at all to the smart device correct?

[Radioguy7268]

Without getting into the weeds of technical jargon - there are design specifications that determine the size of the "window" that a radio receiver will recognize as being a properly configured DPL code. That design window allows you to not quite be exactly on target, but still close enough to the bullseye to count as valid.

 

As long as your radio stays within that window, you're going to operate. Deviate off center a little to the edges, and the receiver might decide that you're not really a valid user. Start outside the window, and then drift into spec, and the receiver might take a while until it decides that you're really supposed to be there, and opens up the audio circuitry.

[lrdchivalry]

Without getting into the weeds of technical jargon - there are design specifications that determine the size of the "window" that a radio receiver will recognize as being a properly configured DPL code. That design window allows you to not quite be exactly on target, but still close enough to the bullseye to count as valid.

 

As long as your radio stays within that window, you're going to operate. Deviate off center a little to the edges, and the receiver might decide that you're not really a valid user. Start outside the window, and then drift into spec, and the receiver might take a while until it decides that you're really supposed to be there, and opens up the audio circuitry.

 

Thanks for the patience and the help. As someone who is not radio savvy, how would I do that? 

[Radioguy7268]

If you don't have the tools for testing, your choices are limited. You can take your radio to a local shop to be bench checked - but checking isn't necessarily fixing.

 

If you've got another radio to try, then you should program that up & see if you have a different experience. If both radios are doing the same thing (but those cheap company radios are not having trouble) - then I think you need to look at the idea that the DPL information on Radio Reference probably isn't correct - it's just what someone's scanner read out.

[lrdchivalry]

If you don't have the tools for testing, your choices are limited. You can take your radio to a local shop to be bench checked - but checking isn't necessarily fixing.

 

If you've got another radio to try, then you should program that up & see if you have a different experience. If both radios are doing the same thing (but those cheap company radios are not having trouble) - then I think you need to look at the idea that the DPL information on Radio Reference probably isn't correct - it's just what someone's scanner read out.

 

I will try using my D878UV and see if I have the same issue. Thanks for the help.

[n1das]

The small radios are from Advanced Wireless Communications and is either their AWR Advantage or AWR Advantage Plus model. Funny, this delay does not happen when using the Advanced Wireless radios. The smart device is the Zebra Industries TC77. As for the app used, I would have to look and see if it shows it. 

 

This system sounds exactly like what (The) Home Depot uses.  The portables I've seen at (The) Home Depot in my area are from Advanced Wireless and have a bridge from the conventional analog portables to the smart devices.  There is nothing unique about the Advanced Wireless portables.  They are conventional UHF portables.  They are low end UHF business band portables.  They are really low end, like the Motorola CLS series UHF analog portables.

 

(The) Home Depot near me uses 467.7625MHz D331N.  "(Musical bleeps) Attention associates!  New order!"

 

The OP should know that the HD1 is a ham radio portable and is not FCC certified for Part 90 use.  The HD1 is not legal for transmitting outside the ham bands in the USA, even if Part 90 licensed and the boss says it's OK.

 

The OP should check that the radio is exactly on the correct frequency.  DPL is sensitive to frequency errors in the transmitter and receiver.  A signal received a couple of kHz off-frequency will cause DPL decoding problems because this introduces a DC offset in the FM discriminator output in the receiver.  The decoder sees a step function instead of the DPL data for a few seconds and causes slow decoding or failure to decode.

[lrdchivalry]

This system sounds exactly like what (The) Home Depot uses.  The portables I've seen at (The) Home Depot in my area are from Advanced Wireless and have a bridge from the conventional analog portables to the smart devices.  There is nothing unique about the Advanced Wireless portables.  They are conventional UHF portables.  They are low end UHF business band portables.  They are really low end, like the Motorola CLS series UHF analog portables.

 

(The) Home Depot near me uses 467.7625MHz D331N.  "(Musical bleeps) Attention associates!  New order!"

 

The OP should know that the HD1 is a ham radio portable and is not FCC certified for Part 90 use.  The HD1 is not legal for transmitting outside the ham bands in the USA, even if Part 90 licensed and the boss says it's OK.

 

The OP should check that the radio is exactly on the correct frequency.  DPL is sensitive to frequency errors in the transmitter and receiver.  A signal received a couple of kHz off-frequency will cause DPL decoding problems because this introduces a DC offset in the FM discriminator output in the receiver.  The decoder sees a step function instead of the DPL data for a few seconds and causes slow decoding or failure to decode.

 

Your spot on about the system and the company. The HD1 is part 90 certified by the FCC, it's certification can be found here. My understanding is part 97 is Amateur/HAM radio, Part 90 is for commercial/business and Part 95 is for FRS/GMRS. If I understand that correctly, the HD1 can be used for commercial/business use. We use 467.7625 as well and DPL 065 is what I got off of radio reference and seems to work except for that delay in the first phone receiving my transmission. The DPL's listed on radio reference are 065 for 467.7625, 331 for 467.8500, 263 for 467.8375, 413 for 467.8750 and 466 for 467.9000. All the freqs listed are all that HD is licensed to use. I pick up that annoying "Attention Associates- New Order" and a few others. Just trying to get that delay worked out.

[n1das]

Your spot on about the system and the company. The HD1 is part 90 certified by the FCC, it's certification can be found here. My understanding is part 97 is Amateur/HAM radio, Part 90 is for commercial/business and Part 95 is for FRS/GMRS. If I understand that correctly, the HD1 can be used for commercial/business use. We use 467.7625 as well and DPL 065 is what I got off of radio reference and seems to work except for that delay in the first phone receiving my transmission. The DPL's listed on radio reference are 065 for 467.7625, 331 for 467.8500, 263 for 467.8375, 413 for 467.8750 and 466 for 467.9000. All the freqs listed are all that HD is licensed to use. I pick up that annoying "Attention Associates- New Order" and a few others. Just trying to get that delay worked out.

 

D065N and D331N are the DPLs I've found the most often.  I'll take a look at the Part 90 cert.  I'm skeptical of the Part 90 cert because the one area where it would violate Part 90 is programmability from the keyboard by the end user.  Under Part 90, the radio can't be anything more than a channelized radio for the end user.  I know some higher end commercial radios have FPP (front panel programmability) but they also include a way in the programming to disable FPP for the end user.  The HD1 would be required to have the capability to disable programming from the keyboard in order to be Part 90 compliant.  I own an HD1 and so far I have only programmed it from the keyboard.  The CPS may have a Part 90 mode for it.

 

I've noticed the deviation in narrow bandwidth mode is a little on the low side compared to other radios I have in narrow mode.  The deviation in wide bandwidth mode is OK.  As for receive performance, the carrier squelch level in wide bandwidth mode is so tight even when set at the threshold that it's practically unusable.  Received signals have to be near DFQ to unsquelch the receiver in wide mode.  Narrow mode works good and reliably unsquelches on weak signals.  The HD1 is a CCR (Cheap Chinese Radio) and works OK for ham use and unfortunately that's about where it ends.  I already knew that when I got the HD1.  The HD1 is one of my throwaway radios.

[lrdchivalry]

D065N and D331N are the DPLs I've found the most often.  I'll take a look at the Part 90 cert.  I'm skeptical of the Part 90 cert because the one area where it would violate Part 90 is programmability from the keyboard by the end user.  Under Part 90, the radio can't be anything more than a channelized radio for the end user.  I know some higher end commercial radios have FPP (front panel programmability) but they also include a way in the programming to disable FPP for the end user.  The HD1 would be required to have the capability to disable programming from the keyboard in order to be Part 90 compliant.  I own an HD1 and so far I have only programmed it from the keyboard.  The CPS may have a Part 90 mode for it.

 

I've noticed the deviation in narrow bandwidth mode is a little on the low side compared to other radios I have in narrow mode.  The deviation in wide bandwidth mode is OK.  As for receive performance, the carrier squelch level in wide bandwidth mode is so tight even when set at the threshold that it's practically unusable.  Received signals have to be near DFQ to unsquelch the receiver in wide mode.  Narrow mode works good and reliably unsquelches on weak signals.  The HD1 is a CCR (Cheap Chinese Radio) and works OK for ham use and unfortunately that's about where it ends.  I already knew that when I got the HD1.  The HD1 is one of my throwaway radios.

 

Ah! I see what your saying in regards to Part 90. Strange that the HD1 is FPP yet still has a Part 90 certification. I haven't seen anything in the cps to disable fpp. Wouldn't want HD to get into trouble for using a non compliant radio. I guess I will just use the crappy radios they have.