KINGSQUEAK.ORG & KC2RGW.COM

So, I’ve had this device for about two years now and have mentioned it to several people on the air, describing just how effective it is.

What is it? This is an active DSP audio noise eliminator filter manufactured by BHI Ltd.. As simply as possible, it wipes out background hash band noise. It isn’t a pulse noise eliminator like a noise blanker, though it will drastically soften the edge of pulse noise as well.

This is an AF (audio frequency stage) DSP unit. It plugs into the audio output of _anything_ you want to feed through it and you in turn loop it’s output into the speaker or other destination audio feed of your choosing.

The unit has either 4 or 8 steps of increasing DSP elimination effects. In stronger conditions you can back it off easily so it isn’t as heavy handed on processing the signals, or in lousy conditions with weaker signals, you can really clamp it down for the maximum effect.

The best way to show you what this does is simply an mp3 file I created to demonstrate its effectiveness.

Here is a 40m SSB clip with the filter being toggled in and out

The clip was made with some high noise levels and relatively low signal levels at or below the noise peaks, using my vertical on 40m SSB.

The DSP setting was on maximum 8/8 so there is some minimal artifact on the audio signal and a very slight audio level drop. Keep in mind the completely annoying original signal. With the DSP engaged it would be easily possible to maintain a pleasant extended contact with any of the stations in the recording, vs only wanting a brief ‘in and out’ style contact before getting sick and tired of the noise level. A slight bit of the ‘under water’ artifact is much more tolerable.

These units are available in a few configurations from BHI Ltd.. They come in built-in modules designed to be hard wired into the audio circuit of a radio or to be built-in to the internal of a speaker cabinet. They also come in self contained powered speakers with the module included internally. Lastly and my personal favorite are the ‘universal’ inline modules. These allow you to use whatever source or speaker you choose by simply plugging in different inputs and outputs to the unit. It’s the most flexible option.

These modules aren’t cheap, but they are worth every cent if you like to spend a lot of time listening.

W4RT.com is one source in the US for this product.

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This map shows ham station beacons and the trails of moving vehicles on APRS

Well my IF tap worked great for a few hours and after I shut down my rig….signals were not right. I learned what seems to be a fundamental lesson about JFETs…they don’t like static much. I’m 99% sure that I zapped the JFETs in the buffer amp I installed after doing some reading on how static sensitive they are. At least my rig is just fine otherwise.

So I got an alternative design buffer amp that’s sitting here waiting for me to pop the hood again and install it. This one doesn’t use JFETs, so my gorilla paws without a static mat won’t be as likely to cook it.

In other news, I’ve rewired myself again for packet radio and APRS operations. Using Xastir on Ubuntu linux, I’ve had APRS up and running a few days consecutively here and there. Pretty neat stuff and can be _very_ handy for any mass deployment events.

In a nutshell, APRS takes GPS coordinates or other information and sends it out as a beacon via radio. So if I’m running the mapping and client software and you are in the field with a handheld running APRS, I can see your position as it is beaconed every few minutes overlaid on a map.

If you are providing event support over an entire marathon course as an example, as the control operator or other field station, at a glance you would be able to see the location of all your operators. This becomes important when you get a call that a runner or rider has been injured and needs first-aid. The closest support vehicle can be instantly located. Not only that, but you can follow that vehicle on the map and know when it arrives at the hospital or control point.

You can beacon most any data up to a limit of 40 characters per beacon. Commonly people beacon their position and then a frequency they are listening to. This way when you see them up close, if you see them you know how to reach them. It can be fun while traveling around just to make contacts as you ‘run into’ them.

Generally this is all done on the 2m ham band for local coverage. But even with that system, there are facilities to repeat or ‘digipeat’ the traffic a station hears. So if I beacon, a station within range will hear it, and then transmit again. Yet another station further out will pick that up and repeat it again, and so on. Add that it is also possible to send the data out to the internet from home stations and you can reach pretty much anyone on the network, world wide.

There are even low frequency links that will broadcast the traffic hundreds or thousands of miles in a single hop. This can all be incredibly useful in the even of a major disaster that knocks out telecommunications services. Hams have the ability to set up field stations with these capabilities in a matter of hours. It’s something not often remembered about this ‘hobby’ as witnessed here ARRL article about the Haiti earthquake

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It’s indeed been a scanner day here at the shack. After having it annoy the hell out of me for several years, I finally got around to replacing the EL (electroluminescent) back light for the display on my old Radio Shack Pro-2006 scanner.

Found the tips on how to do it at Radio Reference thanks to one of their forum users. The part was all of $3.50 from All Electronics one of my favorite quick grab parts-bin sites.

Now it’s as bright, if not a bit better than it was new, 15+years ago.

The surgery to do it was a bit deeper than I’d expected with a few annoying ribbon connectors to un-wedge and the usual myriad of small retaining screws, but once the adhesive blob was cut and the two leads desoldered, it was a piece of cake getting the new EL panel in there. Worth doing.

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I’ve always liked scanning receivers, radio of any type really but scanners are an addiction. For some reason I’d taken a break from running scanners for a number of years and recently I dusted off some of my old reliables and remembered how much I enjoyed general public service monitoring.

I decided to take the plunge and get the latest and greatest digital and trunking capable model to augment the old reliable Radio Shack Pro-2006 that is still humming along. This gives me the capability to monitor the newest radio systems as they come on line in the area.

Currently in my part of NJ there are not that many digital systems, but across the country they are coming on line very rapidly, so if I was doing any traveling this new portable would come in quite handy.

I’ve only had this for a few days now and it’s taken a few days just to get a basic handle on all of the features. This thing has any feature I could have imagined missing on the old banks based scanners I’ve owned before. For anyone considering either the Uniden 396/996 or GRE PSR500/600 series, you simply *must* anticipate using software to manage the memory systems and also anticipate using an online database for frequencies if you truly want any ease of use.

So what are some of the advancements vs my scanners of olde?

Sheer capacity. My Pro-2006 was considered a very high capacity scanner when I purchased it with ten banks (selectable groupings) of 40 channels for a total of 400. I used to think I would never be able to fill that up. The 396XT has a capacity of 25000 Channels! Suffice it to say I think I could program most of the entire East coast with the capacity this thing has. With programming software linked to the on line frequency databases, you can put an awful lot into the unit in a very short time.

Memory management. In the old days you had the bank system. Ten banks of 40 channels as an example. You use the banks to turn scanning categories on and off. Putting police or the local town in bank 1 and adding neighbouring towns or other categories in the other banks. This is a fairly simple system, though if you only have ten channels in bank 1 that you want, you wind up leaving 30 unused memories blank. This is very wasteful. Also the old scanners only showed you the frequency information on the display. This made it hard to know who was talking as you had to memorize them.

The new world has gone to an object oriented approach that takes a bit of fiddling to get one’s head around. There is a hierarchy of categories. System/Site, this is the top of the chain, generally a regional name, though you can make it a top level category of frequencies as well. Next up is the Group, a sub category, a township name as an example or “fire analog” or “fire digital” if you wanted to group in that way. Then finally inside the groups are the frequency entries.

There is then a ‘cross index’ of sorts. So you have your System->Group->Channel hierarchy, you can then tag those with ‘quick keys’ or index numbers that serve to enable or disable them on the fly. This allows you to do a quick select of a global category for monitoring. In trunked system mode you have System->Site ->System Frequencies->Channel Groups->Channels.

An example that I’m using

For daily scanning I have two main System categories, “Home” and “Locals”. Home consists of my immediate town and the singular bordering townships. The groups underneath “Home” are named for the neighboring townships or miscellaneous categories of other immediate resources like “ham repeaters” Locals are the next ring of neighboring towns, two or three towns ‘out’ from where I live. Places I can clearly hear on the portable and may be of interest. The groups inside Locals are also townships or general categories.

Now, Home and Locals have a quick key of 0 and 9. So while scanning I simply enable those two quick keys and those two systems are in turn actively monitored. Inside the Systems, I have the groups. Each of those group assignments have their own ‘quick keys’, the purpose of this is that I can enable Home and then enable and disable the groups inside Home itself. Example, enabling Home and the group quick key for my township only if I don’t want to hear the immediate neighbors for some reason.

O.k. so you have that control…what if you have say a public works frequency in the local town grouping but you don’t normally want to hear that? You simply use the old style lock out function. This just blanks the channel while scanning…skips right past it. You can manually queue it up if you like or unlock it if you want to hear it for a specific reason. Alternately you can make groups like mayberry-PD mayberry-FD mayberry-MISC and assign each of those a GQK (group quick key) so you can simply enable or disable them with the group quick key.

This is a bit complex, but it is extremely powerful and leads to fantastic flexibility if the user just takes some time to adjust to it and figure out how they want their own categories laid out. After four days or so now, I’m still in the process of optimizing the layouts for my general preferences.

As mentioned earlier, software is absolutely *key* for managing all of these categories. I am using Freescan , a free application that is under rapid and current development and supports all the features of the very new XT model that I own.

One of the huge functions that Freescan provides is the ability to import files locally, save your configuration locally and the big one…use an internet connection to an online database and load frequency plans that way. I highly recommend Radioreference.com they have free access as well as a subscription that permits online loading directly from their database. The site is also a fantastic source of information on most models of scanners and information on the monitoring hobby in general.

Enough rambling, I tried to keep this as much to the point as possible, but it’s a ton of information to cover. Suffice it to say, if you are looking for something to entertain you for days at a time, the newest scanning receivers from Uniden and GRE are simply incredible.

A few links on the topic:

Some Vendors:
Scannerworld.com A vendor that provided quick service that I recommend.
Universal Radio Another vendor that I use as well, also recommended and have a great site for pictures of the products.
Uniden/Bearcat Main Product Site
GRE America Main Site

General Information Resources:
Radioreference A site with a frequency database, live audio feeds of scanners, a wiki and active forums…highly recommended!
Uniden Product Wiki Reference The home of a lot of their on line info on scanner operation.
Eham.net Scanner Reviews Take with a grain of salt
For publications, there are Popular Communications and Monitoring Times both have been around for quite a while.

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