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Re: [RFI] DSP for a noisy environment

To: rfi@contesting.com
Subject: Re: [RFI] DSP for a noisy environment
From: Leonard Halvorsen <lhalvors@pppl.gov>
Date: Fri, 21 Feb 2014 18:15:31 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Is the station to which you refer located in some sort of local Federal
Building up there in Albany?
Maybe you could put some sort of small shield-room enclosure up on the roof.
Put the station in there, and do a remote access kind of thing.

You might be able to get some funding from DHS.

If there is a COTHEN facility in the area, you might be able to access that
via the web, or maybe install your station there with the other comm.
equip. and access it independently of the other COTHEN Resources.

Is there a HFGCS Facility on Stewart ANGB down in Newburgh?
Maybe you could remote some equipment there.

A local organization of some sort put a non-Federal-owned NOAA WX Broadcast
outlet up on one of the ski slope mountains some years ago, up near the
Chestertown or Warrensburg area, I think. A remote there? (KW2Q, ex-N2LAQ
was involved with that.)

Or maybe over on Albany Airport - they CERTAINLY can't tolerate RFI there!

On RPI Campus, maybe?

Or, one of the facilities of the Champlain & Hudson Canal?

Heck, the State Police Barracks outside of town.


On Fri, Feb 21, 2014 at 5:25 PM, Dale <svetanoff@earthlink.net> wrote:

> Bruce,
>
> You certainly have difficult circumstances.  The usual suggestions are to
> get rid of (or reduce) the external interference.  I understand that you
> can not.  Two thoughts come to mind:
>
> 1.  Use digital HF communications, rather than voice.  If the noise floor
> is as broad and as high as what you say, S/N ratios will be very poor and
> even good DSP may not be able to handle the problem.  I'd suggest seeing if
> someone in the group has a state-of-the-art rig you could borrow to see if
> DSP can solve the problem in voice mode.  If not, then using a compatible
> digital mode might work, but the stations at the other end of the circuit
> would also need to run the selected mode(s).  The idea is that required
> bandwidth for some of the current digital (non-voice) modes is narrow
> enough to produce usable S/Ns, which is the key to communicating.  Some
> ARES ops in Iowa are currently experimenting with this approach on 75m.
>
> 2.  Consider a remote base operation if your op center location is
> relatively free of RFI on 2m and above.  Use VHF or UHF from your operating
> location in the high noise HF district and handle voice communications via
> a remote base that can (hopefully) be tuned to whatever HF band and
> frequency you need.  This approach at least has the advantage of not
> requiring the station at the other end of the circuit to have non-voice
> data capability.  You need only have an assured line-of-sight path from
> your operation center to the remote base site.  I believe that there are
> several rigs on the market capable of this duty, one of them being Kenwood
> TS-2000.  I have made several 10m contacts with West Coast hams using a
> '2000 up in the hills or mountains and the op being in his car or walking
> with a VHF/UHF HT somewhere and running the '2000 as a remote base.  It
> seems to work well.
>
> Let us know what you decide to try and how it works (or not).  Best wishes.
>
> 73, Dale
> WA9ENA
> EC for Jones County, IA
>
>
> -----Original Message-----
> >From: wa3afs@nycap.rr.com
> >Sent: Feb 20, 2014 12:05 PM
> >To: rfi@contesting.com
> >Subject: [RFI] DSP for a noisy environment
> >
> >I am the Regional SKYWARN Coordinator for the NWS, Albany NY which serves
> 4 states, 19
> >counties.  Mountains prevent much access via UHF/VHF and we want to be
> able to
> >communicate without IRLP, etc if there is something major.  Also HF
> access to other NWS
> >stations would be nice.
> >
> >At this point, HF (80 and 40 meters) is totally unusable due to RF hash
> likely generated by
> >plasma monitors, computers, miscellaneous weather equipment, and nearby
> 'stuff' from the
> >Nanolabs that are in the same building and surrounding buildings.  (Can't
> change the
> >environment)
> >
> >We presently have an older Ten-Tec that has no DSP and are now searching
> for something
> >better.
> >
> >Any suggestions for a modern rig that is:
> >*   Probably less than about $2000 or so (I have no idea how much funding
> we will have...it
> >    may even be less)
> >*   Easy to use by operators that may have little or no experience with
> HF rigs
> >*   Great DSP to cut through the hash
> >*   Built-in antenna tuner would be nice, but we do have a small LDG
> tuner already.  Antenna
> >    is an off-center fed dipole.
> >_______________________________________________
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> >RFI@contesting.com
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>
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