Hi Al, and the group,

I have spent some time in the parking lot of the nearby HRO store in Salem NH, and my measurements agree with your results. One advantage is that it sits in the TCP stack, so "everything" works with it, but some serious disadvantages are there if you try to do anything requiring speeds comparable to (home) broadband performance. On the other hand, most AX25 applications require a dedicated software interface between the computer and the AX25 hardware, and then you get into the Windows/Mac/Linux problem, and other configuration issues that are app-specific.

I have not been able to do any tests with hidden transmitters, much less multiple users, but my guess is that your estimate is correct as well. One of the reasons why I can't do any more testing is because of the dearth of ID-1 users in this part of the US. And that is sort of a chicken-egg problem because of the lack of 1.2 GHz DSTAR repeaters, and their lower range, here in the New Hampshire hills.

If you decide to sell yours, let me know. I might want to put it in my XYL's car, and we can text each other. It should be fast enough for that.....

During my testing I was capturing everything coming and going from my laptop using tcpdump(8), and I duplicated the tests with a Windows machine using Wireshark. I was surprised with the amount of incidental TCP and UDP traffic that was coming and going from background (hidden) apps and the OS, in both cases. This is not a big deal with broadband or fiber speeds, but when you are slightly faster than dialup, it starts to be a significant percentage of the total, not to mention causing the transmitter to engage without apparent reason (and thereby adding to the channel congestion).

73,
Dave
KZ1O

--- In D-STAR_23cm@..., "let_cyber" <kb2ayu@...> wrote:
>
> I must say I agree with the assessment by KB9MWR regarding the so called high speed digital data. [...]
>
> I have done some tests to a DD gateway and used several internet speed tests to get a throughput of about 70 to 90KBps. That was with me as the only user. Add more users, especially hidden users, and I'm sure the speed would drop like a rock.
> [...]

> Sorry for such a negative post. I might be selling my ID-1 soon.
>
> Al
>

I must say I agree with the assessment by KB9MWR regarding the so called high speed digital data. The DD is so poorly impemented that hacking into the modem and running AX25 would probably be better. Full duplex would certainly help, but why bother, off the shelf WiFi gear is much cheaper, much faster, and much easier to configure.

I have done some tests to a DD gateway and used several internet speed tests to get a throughput of about 70 to 90KBps. That was with me as the only user. Add more users, especially hidden users, and I'm sure the speed would drop like a rock.

Worst of all, there is no way to tell what the quality of the link is. Strong signals don't necessarily mean good signals, but with this system you absolutely need a strong signal.

Sorry for such a negative post. I might be selling my ID-1 soon.

Al

The question is not if the unit has failed, but if the unit is in range
of an "access point" (DStar repeater, Mesh node, or 4G wireless tower)
at any moment in time.

I've uploaded a diagram of the proposed system. This entire setup is
going to be installed on my pickup truck along with hard mounted
antennas, and a 30ft pneumatic mast for the rare occasions where I can't
establish a link with the antennas mounted to the overhead rack.

Hehehe (let the flame wars begin) The portal computer is going to be a
windows box running IIS with all the portal software written in C#..
I'll do my best to keep it clean enough to port over to a Linux/Mono
server if anyone is interested. The portal database will be MySQL so
that will not be an issue. I've been programming C# and ASP.NET for the
last 5 years and I am quite sick and tired of having to do all the low
level grunt work in PHP that gets done for me automatically when I'm
working in C#.... especially when it comes to accessing databases.
Hyperlinks are DEAD -- give me AJAX :) RAD to the HILT :)

When I talk about services on the portal, I mean things like a webmail
system tied into Winlink, a Weather Radar web app that downloads and
caches the imagery so that instead of 20 people downloading an image
every 5 minutes, the server downloads it once, and then serves it out as
needed to the 20 users (thus reducing the on air traffic to a minimum).
A full blown DotNetNuke content managment server with forums, news/RSS
feed capability. The "mini" server will be the one built into the public
access router in case the portal server fails, and it will not be
capable of granting access to the backhaul networks unless I decide to
add an SD card to store the login and service databases.

99% of the time, end users will have access to everything they need on
the portal. Only on rare occasions will an end user be allowed any sort
of direct access to the backhaul links. When backhaul access is granted,
it will be handled by opening holes in the firewall specifically for the
services that the specific end user is allowed to access, as defined in
the portal servers database.

erwestgard wrote:
>
>
>
>
> --- In D-STAR_23cm@...
>
> wrote:
> >
> > Has anyone put together a program that will periodically test data
> > connectivity to the current "access point" (dstar repeater), and if
> that
> > repeater is non-responsive, automatically switch through a list of
> > repeaters round robin until it finds an active connection ??
> >
> I'd need to see a diagram here. BTW we have never seen one of these
> units fail. How I might set this up is to have the mini web site on
> the Linux computer behind the repeater. The Linux box would have
> connectivity to various services and each would be a hyperlink. If
> your goal is to reach the Internet, you could try several ways= try
> each link in turn, which might each be a proxy server.
>
> Mini Portal Web Site
> - Internet via 3G
> - Internet via WiFi
> - Internet via DSL
>
> I have convinced our group to not put Internet on our primary access
> points. This way they cannot be hacked, and routine Internet access
> via this system is not part 97 friendly by my reading of it.
>
> If you *have* to have Internet, you can bounce via the repeater to an
> ID-1 someplace that is on someones cable modem, etc- and set up a
> remote gateway. Mixing Internet traffic into our limited half duplex
> links risks overloading them, but if you control it you can be OK.
>
> If you have Linux at both ends you could develop some scripts, etc
> that would test this.
>
>