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Author Topic: Building your own digital network  (Read 8370 times)

WA4STO

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Re: Building your own digital network
« Reply #15 on: July 24, 2013, 04:56:56 PM »
Wally - my apologies for not having seen this for a couple of weeks.  Good info, and it's got me thinking.  Again. 

What I've been wondering now is how the guys who scan multiple bands do so with regard to antennas.

In my case, I've got things set up such that I'd have to manually twist and twiddle  my Palstar tuner every time I want the 270' loop to miraculously become 'resonant' on the new band.

I'm guessing that the guys who are more or less successful do it by way of a multiband vertical which kinda/sorta works although not very efficiently.  No tuner needed there.

Or perhaps a fan dipole of some sort.  Anything that doesn't require a tuner.

O.T.O.H. my IC-7000 does have an automatic tuner, and I THINK I can set it up so that it will always 'tune' whenever it transmits.  Would that work, maybe?

Still, it would have to be resonant somewhere.  Say 40 meters at a given time.  Meaning that it wouldn't hear (not very well anyway) something coming in on 80.

I'm confused.  Being a ham for 43 years will do that.  Maybe I should pretend I'm a newbie again.  Wait, that was no fun either.

73

Luck, WA4STO

Quietguy

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Re: Building your own digital network
« Reply #16 on: July 24, 2013, 06:19:42 PM »
All of my scanning has been done with wire antennas and an LDG RT-11 auto-tuner (hereinafter called "auto-coupler" to keep RadioRay's teeth from being ground down completely) that is controlled by an IC-706MkIIg. I have used an 80m dipole/doublet fed with window line as well as a coax fed 80/40/20 fan dipole.  Right now I'm using the 80m legs of the 80/40/20 fan dipole because the 40 and 20 meter legs fell.  Time for some maintenance I guess; it works fine on 80 and 20 but high SWR on 40 (even multiple of 80).

I have lots of trees but not lots of help, so I am usually putting these things up by myself.  So, I have cut the wire lengths to be reasonably close but rely on the auto-coupler to bring it in.  That hasn't been a problem - when the station is scanning and a call comes in, the radio will automatically go into "Tune" mode when it keys up.  The RT-11 finishes matching quickly enough to allow the connection to be established normally.  When the connection is finished the system resumes scanning.

The RT-11 auto-coupler has been discontinued but current LDG models are superior, in that they have memories and will recall match settings for frequencies they has seen before.  That (allegedly) shortens the cycle considerably, but the time delay has not been a problem for me.

When my antenna was in good shape scanning 80, 40, 30  and 20 meters was no problem.  30 sometimes gave a little RF in the shack and if I were going to do another fan dipole I might consider adding 30 m legs to it.  What I'm actually planning is a 110 foot window line fed doublet per the DX Engineering recommendations for one of their baluns.  They say it is good for all bands if the feedline length is correct and it is mounted less than 1/2 wavelength above ground - which for 80 m is about 130 feet.  I'll only be up about 50 feet, which is where I was before.

Wally

WA4STO

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Re: Building your own digital network
« Reply #17 on: July 24, 2013, 07:28:47 PM »
Wally -

I never would have guessed that the LDG (which is what I have as well) would do such a wide amount of tuning.

I really should put it back in line and see what happens.  I'm guessing that I'll have to come up with a balun first.

All of this is pushing me to the point where I may opt for the SCS modem rather than the HF amp.

Since you brought up Airmail previously, here's a change of topic for ya:

I've been looking for a way to run a 2 meter packet BBS and I wasn't too keen on the idea of going with something as complicated as BPQ, although that was at one time my favorite choice.

Today, however, while digging through Airmail, I discovered that there's a "VHF Packet Server" setup routine.  Hmmm!  What do you know about that?  Should I expect to be able to use Airmail (already familiar...) for that?

Trying to think down the rut a piece, I can't help but wonder how 'automatic' such a BBS would be.  And I'm wondering if, somehow, it's smart enough to know how to take traffic in on the VHF packet side, and magically format said traffic so that it will somehow be OK on the HF Pactor side.  Think that might be possible? 

I have no difficulty with the notion of having to manually format what little traffic I might get before it gets transported over to the HF side, but I am puzzling over what value there would have been if the Airmail coder(s) did NOT make that occur automatically.

Best 73

Luck, WA4STO

Quietguy

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Re: Building your own digital network
« Reply #18 on: July 24, 2013, 09:00:05 PM »
I don't know about Airmail's packet server - I have used the Airmail packet client and it works like the HF client only maybe a little less stable.  A local friend was trying to set up a peer to peer vhf network and had problems.  He and I tried several experiments linking through a digi-peater and had limited success.  It turns out my signal to the digi-peater is marginal; sometimes it works and sometimes it doesn't. 

However, he set up two stations at his home and had problems consistently linking between the two using Airmail.  Sometimes it worked flawlessly but occasionally it would go deaf and wouldn't connect.  The only way to recover was to shut down both instances of Airmail and restart.  Then it would be fine - for awhile.  While we were trying our experiments we experienced the same failure but it was hard to get a feel for what was going on since I didn't have a reliable link to the digi-peater.  As far as I know he was trying to use Airmail Packet client peer to peer; I don't know if he tried the packet server.

I don't have VHF simplex paths to any locals running Airmail so I haven't explored it too much.  It works with WL2K if my signal is good to the VHF-RMS, but that is hit and miss.  I'm surrounded by lots of hills and trees.

I haven't gone through the specs of the new SCS modems, but my PTC-IIex does both HF and VHF but not at the same time.  I have to shut down the HF terminal to open the VHF window (actually, Airmail does that automatically).  Fortunately, no cable changes are required because Airmail automatically switches the IC-706 to the right band/frequency.  The PTC-IIpro would do both simultaneously with two radios, but it required adding another module to the base modem, which upped the price noticeably.

Anyway, it looks like the VHF packet capability of Airmail could use some improvement, but it is not likely to happen.  Airmail has been flawless - for me - on HF and that seems to be what the author was concerned with.  The WL2K people have moved away from Airmail and strongly endorse RMS Express... but RMS Express does not support peer to peer on VHF packet, although it does on HF.  That's what put my friend in a bind - RMS Express doesn't support VHF peer to peer but Airmail does... but Airmail seemed to be buggy on the VHF side.

I have not worked with RMS Express or any other WL2K-developed software so I don't know what their capabilities are or how they would fit in with a "private" mailbox system.  I guess I should load RMS Express and quit guessing about it.  It's just that Airmail on HF has met my needs for so long that I don't often think about alternatives.

Wally

Rob_ma

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Re: Building your own digital network
« Reply #19 on: July 25, 2013, 11:38:27 AM »
Are there any good newbie books/websites available? I know someone who would like to get into digital comms but will be starting on the ground floor. They would like some basic info to build up their knowledge base.

- Rob

Rob_ma

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Re: Building your own digital network
« Reply #20 on: July 25, 2013, 12:13:40 PM »
Thank you. That is a good start for him and I'll pass along your offer. He has technical experience but not in radio (which I am slowly correcting ;) ). He's the type who reads a mountain of information before he jumps in to get his hands dirty. I told him that real techies don't RTFM (Read The "Fabulous" Manual). :D

Any other recommendations are appreciated.

- Rob

K0DEN

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Re: Building your own digital network
« Reply #21 on: July 25, 2013, 11:40:06 PM »
Anyway, it looks like the VHF packet capability of Airmail could use some improvement, but it is not likely to happen.  Airmail has been flawless - for me - on HF and that seems to be what the author was concerned with.  The WL2K people have moved away from Airmail and strongly endorse RMS Express... but RMS Express does not support peer to peer on VHF packet, although it does on HF.  That's what put my friend in a bind - RMS Express doesn't support VHF peer to peer but Airmail does... but Airmail seemed to be buggy on the VHF side.

My humble self just pulled up his RMS Express client and was able to select Packet P2P under his Open Session dropdown. In fact, it appears the only P2P they haven't (finally) implemented is Telnet.

Or am I misunderstanding? I haven't used it, yet, I don't know anyone else here who would use P2P packet as they would either use Winmor P2P or WL2K, or they would use Packet WL2K.

Quietguy

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Re: Building your own digital network
« Reply #22 on: July 26, 2013, 03:54:32 AM »
No, I don't think you are misunderstanding - either I misunderstood my friend (although I don't think so) or his version of RMS Express is older and that function has been added.  I probably should load RMS Express myself and see what it looks like.

Thanks for the comment; it has me curious what happened on his end.
Wally