DF Gear Evaluation

[Capt Rivera]

ND Wing is looking to communicate with other wings who have evaluated commercially available DF Gear. We are looking to replace antiquated and inoperable L-Pers with one of the newer commercially available products. We wish to standardize on whichever product is selected which makes a cost benefit analysis and a comprehensive comparison all the more necessary.

We anticipate that other wings have had the need to update aging equipment as well and hope that evaluations have been made. We desire to gain as much knowledge possible from your reviews while also looking into the concerns ourselves. Please feel free to post any review you might have or let me know if you wish to communicate more directly.

Although limited experience reviews might prove helpful, we are looking for comparison of products which we believe might paint a clearer picture.

Any assistance you may provide is greatly appreciated.

[Eclipse]

I wouldn't allow any of my units to buy anything until the ELT issues are sorted out.

This stuff is too expensive to be sitting on new doorstops in a year or two because we're out of the DF business.

[davidsinn]

I wouldn't allow any of my units to buy anything until the ELT issues are sorted out.

This stuff is too expensive to be sitting on new doorstops in a year or two because we're out of the DF business.

Even 406s need DF'd from time to time.

[Eclipse]

I agree, but my point is that out mission ops tempo has not increased or changed to the degree that existing equipment
doesn't meet the need.

The cheeseblocks are too expensive to risk not needing them, the Pro-Finds are junk, and you're not going to catch me letting my
people spend money on a DF kit in an Altoids case.

[davidsinn]

DF kit in an Altoids case.

You have my attention sir. Please share.

[Major Lord]

David,

I am sure Eclipse is referring to an article I wrote for the CAWG Magazine that was republished in a few other Wing's magazine too. At one time, I offered a single channel ELT receiver on 121.5 as a simple kit with a bargraph display and tiny speaker, for use with a Yagi or other directional antenna (the last one I built was for one of my Cadets who went to GSAR, and needed a personally-owned tracker: Jerry, you can Chime in here if you want) I found most CAP people did not want a unit that could not operate on the practice frequency. (Most CAP members can find time for a SAREX, but actual missions are just so darned inconvenient!) My little hand-helds went mostly to Sheriff SAR teams on a budget.

I am not aware of anyone making a specific ELT DF unit out there besides L-Tronics. The ACR units are designed for water, and have simply awful terrestrial performance. We had a couple of CAP members working on a product named after a large Asian feline, but they could never seem to actually produce one. Its not what you would consider to be a mainstream electronic product, its a niche.

A DF unit that can receive 121.5 will always be of value, so you won't be throwing money away from planned obsolescence. The bigger question is how much CAP will be in the DF business with the next-gen ELT's. ( and EPIRBS, PLB's, etc) I doubt that CAP will be buying hand-held DF units that will directly decode the data stream of a 406 type unit, too much money and not enough field value.

Becker makes a very nice unit for aircraft, and it will decode the data stream from a 406 unit. It costs about as much as a used Cessna.....Individuals wanting field-portable units have a few options. The Australian MK4 DF receiver is pretty good, and I think they will do a special "low band" (121.5) unit on order. There is a variety of ham-type "fox hunting " gear that can be adapted for ELT use.

FYI,  Pretty much any L-Per can be repaired, and since you own them ( and can get a budget for repair more likely than getting a budget for buying new and untested gear) a repair is a wise investment. Bells and whistles notwithstanding, the old L-Per works better than pretty much any product out there.

I considered building a multi-channel DF receiver, but the cost of low-volume production tends to drive me away from it. As an Engineer, my tendency is to want 121, 243, and 406 , plus data decoding, and this gets expensive fast. The other option is to do a bare-bones unit like my Altoids box but with a frequency agile ( and more expensive) receiver. The other frequency and modes may not really be particularly important in field operations.
I manufacture APRS "Micro-Trak" trackers (www.byonics.com) so a slight detour into DF gear is not too much of a reach, but I am just not sure there are more than about 8 guys out there who would buy them!

Major Lord

[CommGeek]

What ELT Issues?  all beacons 406 and 121.5 transmit a 121.5 homer signal.  You cant DF a 406 data burst unless you have a Doppler DF.

So any DF that will receive 121.5 will work.  even a cheap air band scanner works, if you know how to body block and freq offset.

[JC004]

I know of a unit off hand which has both.  I could refer you to one of their guys and you could ask him for his assessment. 

[davidsinn]

David,

I am sure Eclipse is referring to an article I wrote for the CAWG Magazine that was republished in a few other Wing's magazine too. At one time, I offered a single channel ELT receiver on 121.5 as a simple kit with a bargraph display and tiny speaker, for use with a Yagi or other directional antenna (the last one I built was for one of my Cadets who went to GSAR, and needed a personally-owned tracker: Jerry, you can Chime in here if you want) I found most CAP people did not want a unit that could not operate on the practice frequency. (Most CAP members can find time for a SAREX, but actual missions are just so darned inconvenient!) My little hand-helds went mostly to Sheriff SAR teams on a budget.


Major Lord

Could you share some more info? Is it possible to build a unit that will work on 121.775 so we can train with it? I'd be leery of taking a unit on an actual if I hadn't trained with it yet.

[Major Lord]

David,

The article is still archived: http://cawg.cap.gov/ec/reprints/SP2006%20FIELD%20MANUAL%20Breathtaking%20Ingenuity.pdf

Building a frequency agile receiver from scratch is quite an undertaking. There are cheaper alternatives.

Major Lord

[RADIOMAN015]

Frankly, why not just stay with what you've got.  LTronics will even repair any unit that breaks.  We've got both the older unit and the newer unit, and they work fine.   We also had a "Pro Finder" for awhile but gave it back to wing, cause it didn't seem to work right.

The overall demand for ground ELT missions, at least in my wing seems to be decreasing considerably.  Don't think it is worth the money to replace anything at this point, only repair if economically feasible, otherwise salvage.
RM

[davidsinn]

David,

The article is still archived: http://cawg.cap.gov/ec/reprints/SP2006%20FIELD%20MANUAL%20Breathtaking%20Ingenuity.pdf

Building a frequency agile receiver from scratch is quite an undertaking. There are cheaper alternatives.

Major Lord

How about one that is identical but only works on 121.775? That way we'd have a training device and then an actual device.

[Major Lord]

I think it would make more sense to have one receiver, since you would have to have the other associated parts and directional antenna. It would cost less than two separate receivers. If I ever decide to build on, I will let you know. We have had some Ham radio Fox hunt people ask about them.

Major Lord

[Jerry Jacobs]

David,

I am sure Eclipse is referring to an article I wrote for the CAWG Magazine that was republished in a few other Wing's magazine too. At one time, I offered a single channel ELT receiver on 121.5 as a simple kit with a bargraph display and tiny speaker, for use with a Yagi or other directional antenna (the last one I built was for one of my Cadets who went to GSAR, and needed a personally-owned tracker: Jerry, you can Chime in here if you want) I found most CAP people did not want a unit that could not operate on the practice frequency. (Most CAP members can find time for a SAREX, but actual missions are just so darned inconvenient!) My little hand-helds went mostly to Sheriff SAR teams on a budget.

Its a pretty simple 121.5 receiver with a strength display on it. It actually helps immensely on a search so have another receiver do that you are not killing the batteries on your L-Per my monitoring.  I also made a yagi to go along with the receiver but have yet to use it on an actual mission.

[Spaceman3750]

Has anyone here ever used one of the MK4's before? I've seen a YouTube video put out by a CAP member and I saw one floating around at NESA, but never had a chance to run down the owner and ask to play with it...

If you have, what was your opinion of it? Better, worse, or similar in quality and reliability to an L-Per?

[Capt Rivera]

I know of a unit off hand which has both.  I could refer you to one of their guys and you could ask him for his assessment.

If you can get me a POC we would appreciate it....

regarding the upgrade: as long as we own the mission, we need to be equipped... We don't want to be that wing who cant do the job when the call comes...

Ever done a wingnall in a van using just a normal radio tuned to the frequency? I have not but one of my members had to not long ago... that's really not acceptable...

[CommGeek]

The MK4 is AWSOME!!!  I own one, and will never use another DF again.

[CommGeek]

Just use a COTS airband scanner with a directional antenna.   Go off freq as you get closer..  It has never failed me before...

[Major Lord]

My distributor uses the MK4 on Foxhunts and thinks its the greatest thing since sliced bread. A Yagi-based system of any kind won't give you sharp bearings like a switched antenna system, but they are far superior for working weak signals.

Major Lord

[JoeTomasone]

A thread on the MK4:

http://captalk.net/index.php?topic=5048.0;all