epfdtracktrunker
Member
What kind of modulation does this use? How is the voice encoded, and is encryption supported?
-
To anyone looking to acquire commercial radio programming software:
Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.
If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.
To obtain Motorola software see the Sticky in the Motorola forum.
The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.
For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).
This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.
Aegis
- Thread starter epfdtracktrunker
- Start date
- Status
CVSD (Continuously Variable Slope Delta) modulation.
It can be implemented with or without encryption.
It's basically the GE / Ericsson / M/A-Com / Tyco (whatever they are this week) version of what Motorola calls Securenet.
It can be implemented with or without encryption.
It's basically the GE / Ericsson / M/A-Com / Tyco (whatever they are this week) version of what Motorola calls Securenet.
Wasn't the encryption marketed as Voice Guard?
N
N_Jay
Guest
mancow said:
I am very sure AEGIS was not CVSD, seems it was one of the early DVSI vocoders.
Now you have me curious. :roll:
:lol:EDIT: OK, did some looking.
It was generally called MBE.
It might have been DVSI (or a predecessor to DVSI), or something somewhat proprietary.
It used GSMK like ProVoice.
Voice Guard was an earlier product that competed with early Securnet.
Aegis competed with early Astro.
Last edited:
I reference to AEGIS:
Does it have to be turned on in a talkgroup all the time, or can it be used only when wanted, possibly using a option key to toggle it on and off? Can it be used for I-Calls?
Does it have to be turned on in a talkgroup all the time, or can it be used only when wanted, possibly using a option key to toggle it on and off? Can it be used for I-Calls?
I don't believe AEGIS can be toggled on and off... remember AEGIS is a voice modulation, not an encryption scheme. For them to switch between AEGIS and clear (analog) voice on the same talkgroup, I would imagine they would have to have the same talkgroup programmed in twice... Once using AEGIS, ones using analog. I can't see this being very practical or useful though. And yes AEGIS can be used on I-Calls. A police department local to me uses AEGIS extensively on all their communications, with the exception of a provincial common analog inter-agency channel.
I found a neat paper describing EDACS and it give a bit of an explanation as to how it all works.
I was thinking that Voice Guard was unencrypted and the encrypted version of it was just called Aegis but now I realize that it's actually another format in between Voice Guard and Pro-Voice.
I thought (Voice Vuard which I thought Aegis too) was just their version of Securenet but it's GFSK. Interesting......
I wonder how the audio quality differs between Voice Guard and Aegis?
http://hamradio.arc.nasa.gov/EDACS_Whitepaper.pdf
2.12 Aegis Digital Voice
Encrypted Aegis digital voice provides a totally secure
communications system even against the most sophisticated
eavesdroppers.
In EDACS Aegis digital voice communications, analog voice is
converted into digital signals prior to transmission, using digital
vocoder technology.
Aegis digital voice is transmitted using GFSK digital modulation over
working channels at 9.6kbit/s, which is the same transmission rate as
that of the control channel. This uniform design provides every
EDACS radio base station with the inherent capability for supporting
Aegis, as well as clear voice and data.
Aegis provides an additional level of security because ordinary
scanners cannot decode it. It also offers a uniform digital
communications solution. In multi-site systems, the digital signal is
maintained throughout the transmission route and decoding is only
performed in the radio units or at the dispatch center. This end-toend
digital transmission design makes EDACS ideally suited to digital
voice encryption.
I was thinking that Voice Guard was unencrypted and the encrypted version of it was just called Aegis but now I realize that it's actually another format in between Voice Guard and Pro-Voice.
I thought (Voice Vuard which I thought Aegis too) was just their version of Securenet but it's GFSK. Interesting......
I wonder how the audio quality differs between Voice Guard and Aegis?
http://hamradio.arc.nasa.gov/EDACS_Whitepaper.pdf
2.12 Aegis Digital Voice
Encrypted Aegis digital voice provides a totally secure
communications system even against the most sophisticated
eavesdroppers.
In EDACS Aegis digital voice communications, analog voice is
converted into digital signals prior to transmission, using digital
vocoder technology.
Aegis digital voice is transmitted using GFSK digital modulation over
working channels at 9.6kbit/s, which is the same transmission rate as
that of the control channel. This uniform design provides every
EDACS radio base station with the inherent capability for supporting
Aegis, as well as clear voice and data.
Aegis provides an additional level of security because ordinary
scanners cannot decode it. It also offers a uniform digital
communications solution. In multi-site systems, the digital signal is
maintained throughout the transmission route and decoding is only
performed in the radio units or at the dispatch center. This end-toend
digital transmission design makes EDACS ideally suited to digital
voice encryption.
N_Jay said:I am very sure AEGIS was not CVSD, seems it was one of the early DVSI vocoders.
Now you have me curious. :roll:
EDIT: OK, did some looking.
It was generally called MBE.
It might have been DVSI (or a predecessor to DVSI), or something somewhat proprietary.
It used GSMK like ProVoice.
Voice Guard was an earlier product that competed with early Securnet.
Aegis competed with early Astro.
Last edited:
Muxlow
Super Secret
I have 2 MRK's one is 800mhz and the other is a vhf. Also have a orion aegis. I have to program my freqs in twice if i want one for digital unencrypted voice and one in the clear. No way to turn it on or off.
But if you are listning on either channels and the other radio transmitts aegis you will hear the digital sound on the one chan, and the decoded voice on the other programed for aegis. And if you transmitt on the "clear" channel you will hear the voice call on both channels.
We haw
But if you are listning on either channels and the other radio transmitts aegis you will hear the digital sound on the one chan, and the decoded voice on the other programed for aegis. And if you transmitt on the "clear" channel you will hear the voice call on both channels.
We haw
For its age and the technology at the time, I always thought Aegis sounded pretty decent.
Sent from my Nexus 7 using Tapatalk
Sent from my Nexus 7 using Tapatalk
RayAir
Member
- Joined
- Dec 31, 2005
- Messages
- 1,930
Company literature states AME vocoder has 8 bands in the 0-2900 Hz audio range and bit allocation is directly proportional to the energy at the instant of the audio sampling.
I have some M/A Com MRK 2's that have one analog channel and one DES encrypted AEGIS channel.
Encrypted AEGIS sounds (to me), a bit better than the old Motorola Securenet. Securenet sounds scratchy.
I wish my radios had a clear AEGIS channel so I could compare the audio quality between the two ( clear AEGIS and enc. AEGIS).AEGIS being digital I don't think you would get the degradation like you do with old Securenet radios.
Another nice feature is that DSD cannot decode clear AEGIS. Use encrypted AEGIS and you are safe from everyone but the Big G.
I have some M/A Com MRK 2's that have one analog channel and one DES encrypted AEGIS channel.
Encrypted AEGIS sounds (to me), a bit better than the old Motorola Securenet. Securenet sounds scratchy.
I wish my radios had a clear AEGIS channel so I could compare the audio quality between the two ( clear AEGIS and enc. AEGIS).AEGIS being digital I don't think you would get the degradation like you do with old Securenet radios.
Another nice feature is that DSD cannot decode clear AEGIS. Use encrypted AEGIS and you are safe from everyone but the Big G.
Yep... Kind of like using VSELP.
- Joined
- Jan 11, 2008
- Messages
- 1,079
Encrypted AEGIS is the same quality as DES/VGS. They all use the same vocoder it's just the way they encrypted the bits that is different.
Same modulation as ProVoice (even uses the same sync bits for the most part). No error correction tho and the weak signal "pops" can be deafening at times.
Same modulation as ProVoice (even uses the same sync bits for the most part). No error correction tho and the weak signal "pops" can be deafening at times.
RayAir
Member
- Joined
- Dec 31, 2005
- Messages
- 1,930
DES vs. VGE
Does anyone know which algorithm would be considered stronger, DES or VGE?
My guess is DES because old GE literature seemed to state DES was restricted for export and VGE was exportable with a license in their time.
However I read that in addition to a 64 bit VGE key, customers can also add a 64 bit word (CUE- Customer Unique Encryption) so that even if someone had your crypto key they still could not monitor a VGE coded message unless they also had the CUE.
Does anyone know which algorithm would be considered stronger, DES or VGE?
My guess is DES because old GE literature seemed to state DES was restricted for export and VGE was exportable with a license in their time.
However I read that in addition to a 64 bit VGE key, customers can also add a 64 bit word (CUE- Customer Unique Encryption) so that even if someone had your crypto key they still could not monitor a VGE coded message unless they also had the CUE.
Hmmm
FYI, that would be "GMSK", not "GSMK". Gaussian Medium Shift Keying, a fairly common and well defined method of encoding data on an RF signal.
- Joined
- Jan 11, 2008
- Messages
- 1,079
I know that VGE+CUE data is technically a longer KEY than DES, but I can't speak for its actual cryptographic strength. If i were to throw out a wild guess, I would say that VGE is some flavor of DES that has been tweaked a little to make it less secure to get around the export restrictions.
It would be interesting to see the actual analysis and compare their operation but VGE is proprietary and not subject to peer review like DES.
It would be interesting to see the actual analysis and compare their operation but VGE is proprietary and not subject to peer review like DES.
RayAir
Member
- Joined
- Dec 31, 2005
- Messages
- 1,930
That's what I was thinking. The algorithm couldn't be analyzed by any academic community,etc so who knows how secure it is.
There's a lot of VGE equipped radios on eBay.
- Status
