Switching to the 10MHz frequency plan
Hi, Can I hear any objections to switching to the 10MHz frequency plan? We'd be retaining the 5MHz bandwidths for now to keep the power spectral density high, it would just be moving the center frequencies onto the 10MHz plan. This switch would let us keep those center frequencies through 2 upgrade cycles sometime in the future: 1) Expansion from 5MHz to 10MHz channels 2) Expansion from 10MHz SISO to 10MHz MIMO Presently our speeds are limited to 10Mbit/sector. Upgrade phase 1 would bring us to 20Mbit/sector without any additional hardware costs. Upgrade phase 2 would bring us to 40Mbit/sector with a hardware replacement of sector antennas and sector modems. Hardware in phases 0 (present), 1 and 2 can happily co-exist within the same region if we take this change. If we stick on the 5MHz plan, any 10MHz hardware will interfere. The 20MHz plan collides with other radios present at some of our sites, so expansion to 20MHz will be difficult, if it ever happens at all. The 10MHz plan should be good for the next few years until we find some better solutions should the need for speed be there. Portland is thinking of bringing up a compatible system so that users can roam up and down the coast without re-programming and they've asked for confirmation on the frequencies. The other benefit of coordination onto the same channel plan is the border between the Washington and Oregon systems will not be full of interference. Users could roam between the systems seamlessly. If there are any objections to switching to the 10MHz plan, please speak up. --Bart
When persons have asked me about the process to switch from the 5 mhz to the 10 mhz bandplan, they voiced the same concern here in Memphis. This sounds like a great solution. Instead of adopting the 10 MHz plan, I recommend that we update the 5 MHz plan to share the same center frequencies as 10 MHz's plan. That way, the configuration you've recommended is concisely documented and recommended to other groups as well. On Wed, Jun 25, 2014 at 1:27 PM, Bart Kus <me@bartk.us> wrote:
Hi,
Can I hear any objections to switching to the 10MHz frequency plan? We'd be retaining the 5MHz bandwidths for now to keep the power spectral density high, it would just be moving the center frequencies onto the 10MHz plan.
This switch would let us keep those center frequencies through 2 upgrade cycles sometime in the future:
1) Expansion from 5MHz to 10MHz channels 2) Expansion from 10MHz SISO to 10MHz MIMO
Presently our speeds are limited to 10Mbit/sector. Upgrade phase 1 would bring us to 20Mbit/sector without any additional hardware costs. Upgrade phase 2 would bring us to 40Mbit/sector with a hardware replacement of sector antennas and sector modems. Hardware in phases 0 (present), 1 and 2 can happily co-exist within the same region if we take this change. If we stick on the 5MHz plan, any 10MHz hardware will interfere.
The 20MHz plan collides with other radios present at some of our sites, so expansion to 20MHz will be difficult, if it ever happens at all. The 10MHz plan should be good for the next few years until we find some better solutions should the need for speed be there.
Portland is thinking of bringing up a compatible system so that users can roam up and down the coast without re-programming and they've asked for confirmation on the frequencies. The other benefit of coordination onto the same channel plan is the border between the Washington and Oregon systems will not be full of interference. Users could roam between the systems seamlessly.
If there are any objections to switching to the 10MHz plan, please speak up.
--Bart
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-- Ryan Turner
On Wed, Jun 25, 2014 at 11:38 AM, Ryan Elliott Turner <ryan.e.t@gmail.com> wrote:
Instead of adopting the 10 MHz plan, I recommend that we update the 5 MHz plan to share the same center frequencies as 10 MHz's plan. That way, the configuration you've recommended is concisely documented and recommended to other groups as well.
This is precisely what Bart is proposing, and once it is accepted (maybe earlier) it will be properly documented. Tom
Ryan, This is precisely what Bart is proposing. As a board member, this plan provides running operations for the forseeable future, provides potentials for higher client speeds in the future, and improves compatibility options with other HamWAN networks. As an admin for the network, this plan provides for the above, plus a small amount of work now, warding off larger amounts of work later. +1 from me. Nigel K7NVH
Shouldn't the 10 MHz Plan be bumped down by 5 MHz(or some other amount) to allow 5MHz as a Guard at the top of the Ham Band Plan? I don't know what is on the other side of 5.925GHz; but I'd assume it could be an issue to us. Has that been discussed before and I just missed it? Maybe just 1 or 2 MHz would be sufficient? We are starting to move forward with the Portland HamWAN. While our frequencies don't have to be the same; it will be simpler if they are. At the ORRC meeting Sunday we discussed the 6cm Ham Band Plan. I am to give a report and recommendation at or before the next meeting. I'll follow your lead on which plan to use. On my initial request I had added the 5MHz for Guard at the upper edge. 73 Ken Tolliver K7ICY Portland HamWAN FYI: Your current HamWAN 10 MHz Plan 10MHz Sector Plan 10MHz guarded 10MHz channels CH Low Center High Bearing 1 5.915 5.920 5.925 0 2 5.895 5.900 5.905 120 3 5.875 5.880 5.885 240 5.925 is the very top edge of the 6cm Ham Band.
On Wed, Jun 25, 2014 at 12:27 PM, Kenneth Tolliver <ktolliver@hotmail.com> wrote:
Shouldn't the 10 MHz Plan be bumped down by 5 MHz(or some other amount) to allow 5MHz as a Guard at the top of the Ham Band Plan? I don't know what is on the other side of 5.925GHz; but I'd assume it could be an issue to us. Has that been discussed before and I just missed it? Maybe just 1 or 2 MHz would be sufficient?
The guard bands were sized by testing. 10 MHz was decided on because that was where throughput speeds were good even with 3 sectors colocated. There aren't going to be nearby transmitters on 5.926 GHz, so we have no reason to bump the guard band down. We might as well use the full ham band. Tom KD7LXL
OFDM is a pretty rectangular emission spectrum (unless you're over-driving your amps), so it keeps pretty tightly to its own frequencies. For example: http://www.dsplog.com/db-install/wp-content/uploads/2008/02/ofdm_tx_spectrum... We haven't experienced issues with anyone above 5925 to date. The spectrum up there is for fixed microwave (think: point-to-point dishes) and earth-to-space (think: giant dishes pointed up). Both types of usage are highly directional, so even if there is some spill, it's unlikely to affect anything. I'm reluctant to pro-actively give up already limited spectrum on the off chance that some day we'll co-locate with a licensed transceiver that does use a frequency low down near 5925 and our sideband is strong enough and the antenna gains are correctly directional enough to interfere. We do spectrum surveys of our sites before we install anything, so that we can better predict if there will be issues. Good point though, and it has been considered during initial planning. Aside from emission frequencies, there's also the consideration of directionality (eg: F/B ratio). That's an area that we can use lots of improvement in. I'm not happy with our present performance there. I heard you guys are planning to use UBNT sectors. We might use them too. Just be aware of their very narrow vertical pattern. It means setting proper down-tilt is critical. I really gotta measure them in full 3D, and with WaveGuards. --Bart On 06/25/2014 12:30 PM, Tom Hayward wrote:
On Wed, Jun 25, 2014 at 12:27 PM, Kenneth Tolliver <ktolliver@hotmail.com> wrote:
Shouldn't the 10 MHz Plan be bumped down by 5 MHz(or some other amount) to allow 5MHz as a Guard at the top of the Ham Band Plan? I don't know what is on the other side of 5.925GHz; but I'd assume it could be an issue to us. Has that been discussed before and I just missed it? Maybe just 1 or 2 MHz would be sufficient? The guard bands were sized by testing. 10 MHz was decided on because that was where throughput speeds were good even with 3 sectors colocated.
There aren't going to be nearby transmitters on 5.926 GHz, so we have no reason to bump the guard band down. We might as well use the full ham band.
Tom KD7LXL
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participants (5)
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Bart Kus -
Kenneth Tolliver -
Nigel Vander Houwen -
Ryan Elliott Turner -
Tom Hayward