Daniels P25 Repeater

[ASTROMODAT]

If anyone is familiar with the Daniels P25 repeater, I have a couple of quick questions:

1. Is the IMBE vocoder contained in the repeater, so the link to/from a remotely located console is carried via recovered analog audio?

2. Does Daniels support encryption? If so, is the encryption/decryption accomplished locally at the repeater (rather than remotely/outboard, such as Motorola does it with their DIU)?

Thanks, in advance, for any help on this.

[wavetar]

We looked at Daniels a little while back. At the time, it was strictly a 'transparent' repeater...no VOCODER at all. Which makes sense...the Quantar is transparent as well. Not to mean it treats the signal the same as a Quantar...it just didn't 'break it down' and rebuild it...along the lines you might be thinking. I do believe a DIU was required for console operation.

Can't answer the encryption question as it wasn't in our scope at the time.

Todd

[ASTROMODAT]

On the Daniels web site, they show an extremely high level abbreviated system diagram that includes an IP connection between their repeater and a standard tone remote. It appears (but does not actually address) that there may be a vocoder in the repeater, as otherwise how would the IP connection to the tone remote be able to carry recovered audio? Clearly, it can not be done on the PC, as DVSI does not supply such a capability for a PC to encode/decode IMBE (other than a $2,200 circuit card that is meant strictly for experimentation and evaluation). Same dilemma exists for encryption. The web site deos not say anything about carrying mixed mode traffic to/from the repeater, nor encryption, so I thought I'd ask. I did not see anything at all akin to a DIU on their site, so I was left wondering. Seems a bit strange that such fundamental stuff like this would not be at least briefly addressed on their site.

[515]

As far as I know, the Daniels P25 repeaters still use Astro Saber or XTS3000 vocon boards in their transmitter and receiver modules. I understand they do have custom/modified firmware in them, though.

All of the Daniels P25 repeaters I've worked with had vocoding capabilities built in. I believe their first generation P25 repeaters simply double-vocoded the voice, but within the last couple of years they were able to do completely transparent repeater operation. On these newer ones, I know that DES/AES, conventional talkgroups, and unit ID's pass through fine.

It seemed they always had a 600 ohm audio input/output on their backplane for wireline control of their P25 repeater/base. I don't believe tone remote was supported in the standard configuration, but I'd imagine they have an optional card for that.

Within the last year, I know they've supported the option of loading a DES/AES key into their transmitter and receiver modules for use as a base station.

I've never really messed with the wireline control functions of a P25 Daniels repeater since they're almost always used at solar powered sites where there wouldn't be any phone lines or IP network.

The Daniels P25 stuff is really easy to make repeaters with cross-band links, so linking or controlling repeaters with VHF/UHF is easily done. The encryption, talkgroups, individual calls, and unit ID's are all transparent on the links.

In my situation/experience, a basic Daniels P25 repeater is priced pretty similar to a Quantar, so I only use them in solar powered applications.

Last I checked, the Daniels P25 repeaters did not pass special Astro signalling such as the phone dialing or page packets.

Also, the P25 "hang time" or "drop out delay" they use on their latest P25 repeaters isn't all that great. It looks like they're trying to send P25 frames of silent audio. So when you unkey, you see your own unit ID on your radio's display... Also, if a P25 radio keys during the hang time, usually the first second or two of their audio is doesn't make it through the repeater, which sucks. So I always have to set the hang time to 0 for P25 Daniels repeaters...

[ASTROMODAT]

That makes a lot of sense. That means the IMBE vocoder must be located in the repeater. But this also means that if you want to connect it to a console that is remote from the repeater, the audio would have to be encrypted/decrypted at the repeater, so the wireline audio would necessarily have to be analog clear.

I believe virtually all Fed LEA's require encrypted streams to be decoded only at the console, and NOT carried in the clear to/from the repeater. Seems like this locks Daniels out from the 3 and 4 digit Federal LEA's. I suppose forrestry and natural resource guys, and FD's, could use it.

[515]

Yeah, that's pretty much how I understand it...

It seems most of their market is natural resource agencies that often don't require much encryption and have a lot of solar powered sites. I think they even call most of their repeaters "mountian top repeaters".

If I had to use a VHF Daniels P25 repeater (solar powered site), and had to have encrypted control of it, I'd try and set up a full duplex UHF link to control it. That way, the encrypted audio would pass through the UHF link to/from the dispatch center, and the repeater/link would never have to be loaded with the encryption keys. Chances are, if you have a solar powered site, you don't have any phone lines at the site for true wireline control either...

Or just use an encrypted VHF control radio for dispatch, which could be a Quantar base at an AC powered site in range of the repeater with phone line access. Then the DIU could be in the dispatch center where it's supposed to be. Still not as good as real wireline control, but solar sites usually require compromises.

[ASTROMODAT]

Very interesting. I still am a little baffled, though. I think the Daniels machine is the same price as a Quantar, and yet the Daniels machine doesn't have the capability of the ASTRO modem, nor even wireline control. On the other hand, you can buy the Quantar and turn the power down for a nice solar set-up. And, with the ASTRO modem, you don't need telco phone lines from the Quantar to the console. You could simply set up a solar powered microwave link, or even a full duplex UHF link, as it only needs an analog 4 wire PL (Type 5 VG-32 3002 4 wire circuit).

[Hartley]

Hi,

I don't think you would find that a Quantar would be useful solar repeater, regardless of how low you turn the power. The Quantar draws over 3 amps @ 12 VDC in receive standby, and this is a HUGE load for the average solar site. The Daniels draws something like 150 ma in standby..

3X24 = 72 ah per day, which would require a minimum of 12 amps of panel to keep running - before you transmit at all!

73 DE Hartley

[ASTROMODAT]

Guess we'll just have to wait a few more months for the low power version of the Summit! BooYah!

[RKG]

Actually, my book shows a draw of 60-65 watts unkeyed, which would be closer to 6A at 12VDC. The unkeyed draw is not sensitive to whether or not the receiver is squelched, since it is dominated by the CW exciter.

[ASTROMODAT]

Let's remember that the Quantar was the first P25 repeater released, way back in 1993. It was designed in the mid to late 1980's, some 20 years ago. It's amazing that it's still the best thing going in terms of a P25 repeater, albeit it may draw almost 3 amps on standby. I think we can rest assured that the Summit will knock our socks off! BooYah!