DF recommendations

[BigMojo]

I outrange the L-Per almost every time, by at least a 1/4 to a 1/2 mile. I'm guessing you aren't pairing the Sniffer with a good antenna when you are searching for AOS.

In Broward County Florida (my main AO) we have 4 airports and thousands of boats along with a Sheriff's Dept that issues PLBs for Domestic Abuse victims....I dare say we are one the more active AOs in the country for ELT/EPIRB/PLB shutdowns (I've had 25 thus far this year, and haven't been on all the missions).

The creator of the Sniffer is very close to a 243MHZ solution and I hope to be Beta Testing a prototype very soon...Once he has that, there's nothing an L-Per can do in relation to our work that the Sniffer can't.

[_]

Please do not read the below thinking I am trying to give you attitude.  My experiences with the equipment is different and I think it was DNall's idea to get multiple views of the equipment.

The sniffer is excellent when used in support of a l-per, not in place of.  A sniffer does not have the range the l-per has.

Wow - I have to wonder how you are concluding this.  I did extensive testing of the L-Per and the Sniffer with several different antennas and the Sniffer always matched/exceeded the L-Per's performance -- on the same antenna.    I get AOS at 2-3+ miles usually with each against a training beacon with new batteries using the L-Tronics mag-mount vertical.

That's based on practical experience by multiple teams on multiple real and training missions.  The difference between performance can possibly be explained by the geography and general make up of the area or where the beacons were physically located in comparison to the ones you did your testing with.  We normally use the dual antennas for the l-per and a whip antenna for the sniffer.  Also most of the beacons I end up going after have expired batteries and are not transmitting at full power.  We don't get many beacons that have fresh batteries.  We've found that l-pers have a max range about 5 miles and sniffer about 1.5 miles.

A sniffer is in the same league as a scanner, tracker, or jetstream radio.  Like those things, you can df a beacon with them but you have to make a lot of allowances for it's deficiencies.

If I had to pick something to disagree with you the most on, this would be it.   A scanner:

1. Does not convert signal strength into a variable-pitch tone, allowing you to discern subtle changes in signal strength

2. Does not feature auto attenutation

My view is that a sniffer, like a scanner or the other items listed, is a close-in piece of equipment.  They work in different ways but I view them as being used in similar situations.

I have to believe that the antenna you are trying to get AOS on is ill-suited to the task or has some other issue.    My experience with the Sniffer is the opposite of yours -- I have no need for the L-Per.

And that is why I said my preference is to favor getting a l-per as opposed to a sniffer.  In my squadron and most of the ones in this area we use both pieces of equipment to complement each other.  I wanted to add my experience into what has already been said.  If you can get away with using only a sniffer then go with a sniffer.  I could probably get away with a sniffer but it would mean completely changing our tactics and would make for more difficult and much longer missions.  If I have to choose one of the two I'd go for the "sure" thing as opposed to the thing that has worked for other people in some areas but not others and should work for you.

I live in a totally different area so your millage will vary.

[DNall]

My experiences with the equipment is different and I think it was DNall's idea to get multiple views of the equipment.

That is correct.

I would probably prefer to go with the new LPer system, but cost is a serious concern. Sending a team out with both an LPer & Mk4 is not even an option.

I got one broke old-school LPer, maybe can raise $750-1000, and I need three DF systems. This is my immediate need. I will probably need 1-2 additional systems within the next 18mos.

I have my experienced unit (2GTs on a bad day), and this off-shoot flight (1GT) an hour SSW of us near the Gulf. They've been operating about a year, starting to mature into ES now. I also have the two after-school programs small but building. It totals out 142 folks on the books.

My Group has about 16Sqs with over 1000 personnel. Geographically, we cover a little under a quarter the state of TX, which includes the whole Houston Metro are, and runs from just west of Victoria in the west to LAWG in the East & Gulf of Mexico to College Station in the North. It's a massive area, with 100k+ epirb equipped boats, 2 major international airports, a military airfield, dozens upon dozens of airports of every shape & size, and thousands of helos spread all over the place.

In other words, a crap ton of missions. I have geographic coverage for roughly 20% of that space on the SW corner between my unit & the attached flight, and right now we're completely INOP for lack of functional DF gear.

Sooo... I need 3 functional systems right now. Fixing the broke LPer is a no-brainer. That still leaves me needing two more at a minimum. I'll throw $200 on this, but the rest has to come from our members, cadets fundraising (which isn't really fair to them to use it for this), or corporate donations.

I agree with the proven technology argument versus taking a chance on a system I don't have a lot of experience with & have only seen a couple times in person, but I'm not sure that's an option financially. If it were possible to equip teams with both systems, I would have just done that & not bothered to ask for input.

[RiverAux]

I'm just about convinced that the sniffer is the way to go based on the testimony here and in other threads.  Although your local tactics may vary, in almost all ELT cases you're either going to a site that has been more or less pinpointed by an aircraft or you get sat hits that direct you to an airport or marina. 

So, even if sniffer range is lower (which I'm not convinced of), the number of times we actually need to groiund DF from miles away is so low as to not worry about.  However, the time that might be saved by quickly pinpointing ELTs the rest of the time seems very real to me.  When you factor in the low cost its about a slam dunk if you're trying to outfit multiple teams. 

[JoeTomasone]

Well, just for completeness' sake, let me describe the testing I did to compare range on the L-Per vs. the Sniffer.


1.  Place the beacon.   This was conducted on top of a vehicle, in a vehicle, laying on it's side inside a vehicle, inside a house, and inside a hanger.

2.  Drive away, with the L-Per connected to the antenna under test (a vertical, mag mount, airband antenna - of which I tried three different antennas, a Radio Shack mag-mount scanner antenna, a 2M 5/8 wave vertical, and a dual-band 2m/440 antenna).   Drive until the signal can no longer be discerned and log the distance.  Connect the Sniffer, verify signal, drive more until the signal can no longer be discerned, and log the distance.   

3.  Switch antennas and repeat the exercise.


In each case, the Sniffer matched or outperformed the L-Per.   Obviously I used these tests to determine which was the best antenna for getting AOS, and it turned out to be the cheapest -- the L-Tronics mag mount.    The Sniffer/L-Tronics antenna combo sniffed a real-life ELT at 3.43 miles (as described earlier).  We tracked it to an airport.  5 minutes after we put boots on the ground, we IDed the aircraft in a hanger with 7-8 other aircraft.    That would NOT have happened with the L-Per -- not in my experience, anyway.

Tonight I assisted one of my Squadrons in conducting UDF training.  We placed a beacon between the tires of a flatbed truck, broke the Cadets and Seniors into 3 groups, and had them search for it.  One had the Sniffer, one had the "old" L-Per, and one had the $2000 Seimac ProDF unit.   Periodically, we would switch.  The 3 teams found the beacon with the Sniffer and could NOT find it with the L-Per or the ProDF.  The ProDF was the most brain-damaged, sending the teams (including me, when I tried it) on wild goose chases.   Even when using it against a known beacon location, we could not figure out how to get it to steer us in to it.   Very disappointed in that unit.   The L-Per teams at least got close.

[JoeTomasone]

I agree with the proven technology argument versus taking a chance on a system I don't have a lot of experience with & have only seen a couple times in person, but I'm not sure that's an option financially. If it were possible to equip teams with both systems, I would have just done that & not bothered to ask for input.

I can understand your dilemma.   Let me say that until you actually use the Sniffer yourself, you cannot and will not have the proper appreciation for it.   I bought mine largely on Ben's recommendation and my own research, and it was a gamble - although relatively minor due to the research I had done and a ham's understanding of the principles involved.   Still, I was amazed when I started using it.   It has exceeded my every expectation, which is why I recommend it with zero hesitation.

I've played with the old and new L-Pers, the Seimac, handheld radios, and the Sniffer and to me there's no question as to which the best SYSTEM is.   Couple that with the fact that it's the CHEAPEST and I can't in good conscience not urge you to strongly consider it.   


BTW, Ben: Were you aware that you can hear reflections with the Sniffer?  It's true. 

[RiverAux]

Maybe I'm asking too much, but shouldn't it be the job of the folks at the CAP National Technology Center to be doing high quality testing of such equipment that is so vital to the most common ES mission performed by CAP?  Of course they are primarily focused on Communications issues, but the DF issue is so similar that they should be able to do such work in their sleep.  

Look at it this way, when we send out a ground team they've probably got several thousand dollars worth of nearly brand new radio equipment with them (mobile and handheld VHF as well as ICOM-type radios), but the DF equipment they're using is probably 25 years old and made in someone's garage with an antenna that looks like a curly straw.  

We've got several brand new DF systems out there that CAP should be testing in a formal situation (multiple units of each system, multiple practice beacon, repeatable tests) so that they can made some solid recommendations on this issue, or better yet, start buying the best model for our units in the field.  

[NC Hokie]

Maybe I'm asking too much, but shouldn't it be the job of the folks at the CAP National Technology Center to be doing high quality testing of such equipment that is so vital to the most common ES mission performed by CAP?  Of course they are primarily focused on Communications issues, but the DF issue is so similar that they should be able to do such work in their sleep.  

:clap:

I've been wondering when this was going to come up.  I try not to be cynical but discussions like this support the idea that local squadrons succeed in spite of the national leadership.  I have high hopes that this will be addressed during Maj. Gen. Courter's tenure.

[_]

Joe what was the terrain and building makeup in the area you tested the equipment?  Our area is many small peninsulas with rolling hills and high building density, being a mix of homes and businesses.

[JoeTomasone]

Maybe I'm asking too much, but shouldn't it be the job of the folks at the CAP National Technology Center to be doing high quality testing of such equipment that is so vital to the most common ES mission performed by CAP?  Of course they are primarily focused on Communications issues, but the DF issue is so similar that they should be able to do such work in their sleep.  

Must. Resist. Urge. To. Comment.

I have exceptionally strong feelings on this subject that would likely get me on MikeWatch, so let me just say that I am more than happy that they are NOT doing so.

[JoeTomasone]

Joe what was the terrain and building makeup in the area you tested the equipment?  Our area is many small peninsulas with rolling hills and high building density, being a mix of homes and businesses.

Well, this *is* Florida, so not much in the way of terrain - which is better for testing IMHO.

Various building makeups, from residential to light industrial. 

Here's a Google Maps KMZ file of an actual mission including merges, aircraft fixes (they didn't have a good day), and the AOS and actual location so that you can see what I was working with.

[BigMojo]

In my area, again Flor-e-duh, the only rolling hills are made of garbage, but, in my zone, we are highly urbanized with High-rise condos as far as the eye can see from the edge of the glades to ocean.

Joe, I did know that you can hear reflections...I figured that one out not long ago...what I found cool is one night we had multiple elt's within 500yrds or so of each other, and I could pick out which was which and DF them individually.

As for NTC, well, I'm more action than discussion oriented, so I went out and read up on everything I could get my hands on for DF'ing, both SAR oriented  and HAM, even hunting dog and animal collar tracking. So, I took it upon myself to get the gear and prove it to the powers that be. Just my style.

If the L-per's process of DF'ing is more intuitive to someone, I say use it, become and expert with it, and do the work. If the Sniffer or the ProFind is, go that way. There is no perfect solution for everyone.

[RiverAux]

I suppose what I was getting at is that no squadron, group, or even wing can really afford to buy enough units to do what I would consider adequate testing of the product.  For example, I would want at least 5 brand new units of each type of new DF gear and depending on example how the testing was set up, would probably need several hundred individual tests to get a good idea of which works better.  It would really be quite a project to do it right. 

[DNall]

NTC should test units to advise the national org on which ones to buy several hundred of. Since they don\'t properly equip us & we have to go into pocket or raise funds, it would be nice to have authoritative expert advice/test results to work from, but not absolutely necessary. In lieu of that, the knowledgeable folks on here work just fine. There\'s enough crap wrong with CAP that it\'s not necessary to crowd the list with this kind of thing.

[RiverAux]

You're right that its not absolutely necessary to have the sort of testing that I advocate, but there is no reason that it couldn't be done by NTC for the price of only a couple of the radios that they're buying and the time to do the work.  Keep in mind that without some good advice based on sound testing, each unit is basically playing a crapshoot on what they buy and as we've seen in this and other DF threads, a lot of units have spent what little money they've got on units that turn out to not be very good. 

[JoeTomasone]

You're right that its not absolutely necessary to have the sort of testing that I advocate, but there is no reason that it couldn't be done by NTC for the price of only a couple of the radios that they're buying and the time to do the work.  Keep in mind that without some good advice based on sound testing, each unit is basically playing a crapshoot on what they buy and as we've seen in this and other DF threads, a lot of units have spent what little money they've got on units that turn out to not be very good. 

The NTC is assuredly buried under the narrowband transition right now.   They also have a lot of radios to (un)certify as being compliant.   

[RiverAux]

Those guys need to think of a new job...they've been messing with narrowband, wideband, galaxy-wide band radio transitions for 10 years.  Aren't we done yet!!!