I'm on a budget

I’m trying to make decisions on whether to put in the stormscope and traffic avoidance systems in my SR22 scheduled for next summer.

Has anyone investigated the TPAS RX-100 Traffic Proximity Alert System @ $595 and AnywhereMaps new weather software? They seem like reasonable alternatives for those that don’t have unlimited funds. If you havn’t seen them check them out at www.surecheckaviation.com and www.anywheremap.com

I’ve been using the anywheremap software on my pocketpc as a GPS for several months in a rental and I’m very impressed with the performance. The wx software options appears to give a lot more information for about a $K buck or so vs the xxxx display you get for $9K bucks. $595 vs $21500 for traffic avoidance…

Appreciate any comments.


I’m trying to make the same decision re the SkyWatch. Regarding the SureCheck RX-100 TPAS, see the http://www.avionicswest.com/articles/surechecktpas.htmAvionics West review.

Not a very favorable review.

Walt: One the point of traffic avoidance, be sure to read the reviews of the Skywatch system posted on www.avionicswest.com and www.avweb.com. Also, if you don’t presently subscribe to Aviation Consumer, now would be a good time to subscribe. See www.aviationconsumer.com for subscription details. One nice feature of aviation consumer is that once you subscribe, you get access to past articles on their web site. They have not only reviewed all of the devices you mention, but they also have published articles on the relative priorities of different areas: eg. training, backup AH, backup com radio, weather avoidance, traffic avoidance, etc. All very informative, and sure to be helpful to your making an appropriate decision. You will immediately pick up the benefit of the last few years of their publication on the web site.

In a sense, you have two different questions. On the traffic avoidance system, you are at least comparing apples and apples. The Traffic Proximity Alert System is looking for transponder replies that are being triggered by ATC radar. It won’t tell you either their bearing or distance from you. There is benefit in the information that there something out there, and it definitely encourages an active scan to try to find it.

On the AnywhereMaps, you are looking not at live electrical discharges but at the government weather radar data. This is the apple compared to Stornscope’s orange.

In fact, Garmin has a unit that will do the same as AnywhereMaps will do. I think it is designated the GDL 49. This device was supposed to be out by the end of this year, but has been delayed. It is a subscription service similar to AnywhereMaps. Instead of AnywhereMaps aviation cell phone link, the Garmin device has a separate antenna that mounts on the roof of the aircraft. It transmits your GPS location data and subscriber code and gets back weather data that will display on the GNS 430.

The Stormscope is a separate category of device, known generally as spherics, for atmospheric display device. Whether you get such a device depends on your geographic location compared to thunderstorm frequency or whether you plan to travel to such areas.

One thing to keep in mind with regard to both Cirrus options is the simplicity and cost advantage of getting them installed at the factory. Both the Stormscope and Skywatch require considerable wiring, mounting of avionics boxes in the tailcone of the aircraft and outside antennas, all of which are time consuming (read expensive) to do later.

Keep reading, consider what kind of flying you intend to do (VFR/IFR) and where, and the decision will become clear.

I have both the Stormscope and SkyWatch on my new SR22. The Stormscope is usually not needed here in California but it certainly was a big help in navigating IFR in between thunderstorms when returning from the midwest. I hope to travel IFR with the plane around the country and real-time information on lightning discharge bearing and distance is a must for this, IMHO.

SkyWatch is tougher to justify (but I love it anyway :>). Aviation Consumer ranks it fairly low on the priority list but, out here in the SF Bay Area anyway, I have found it very useful. It is comforting to have a “third eye” providing a heads up for the traffic the controller is too busy to call for you - and there is a lot of it around here! Of course, elsewhere in the country I flew most of a day without ever seeing another return within the 12 nm range of the system.

In summary, I think the Stormscope is a must for serious IFR use in much of the U.S. The SkyWatch depends upon your tolerance for and exposure to traffic.


Have been meaning to post a PIREP on the Surecheck TPAS. Glad you prompted me to do it!

Basically, the TPAS does what is advertised. It gives visual and aural warnings on transponder equipped traffic (being interrogated either by radar or another active TCAS unit). No heading or altitude information provided. The di8gital distance readout is “reasonably” accurate, though far from perfect.

For me, it provides another reminder to look for traffic, especially on long IFR flights when things get quiet. In busy Class B it is a reminder of how much traffic there is out there that you don’t see and ATC doesn’t call. But, it is reassuring to get a warning and perform a VERY careful scan.

On those occassions when I’ve gotten REALLY worried (traffic 1 mile etc), and asked ATC, the answer has always been “traffic 1 mile, 2000 feet above your altitude” or something similar. But, nice to know.

Given that there only 15 midairs in 1999 out of 1700 accidents, 80% of them in the traffic pattern, I don’t plan to upgrade my $475 TPAS to a $20,000 Skywatch. Even without a budget constraint.

From a safety standpoint, believe you’d be far better off to put the $20,000 in the bank and take $1000 worth of recurrent training every year for the rest of your life. You’d be a safer and better pilot, I assume.

I have the TPAS mounted under the copilot’s instrument panel. Antenna extension cable runs under panel to copilolt’s side of windscreen. Gives a reasonably clean install with very little effort. Can provide photos if desired.


RE: Traffic Avoidance Systems
A friend of mine (in his SR20) uses and likes a competitor to the product you referenced. Check out: www.monroyaero.com .
I have SEEN (not used) both units and plan on the Monroy unit. Functionally similar, but Monroy IS 1/3 THE SIZE (based on volume)! Mountable in or on or under panel much more easily. Price: $789.00

Although I am going to perform a little more research, I’m still interested in the Surecheck TPAS. I appreciate all the comments so far. I just called Surecheck and was told to try the device out for 30 days. If I’m not 100% satisfied with the performance, return the unit for a full refund, with no questions asked! I think they believe in their product


I noticed confusion and misinformation in here, so I thought I would clarify some things.

Some notes about The New Collision avoidance units, and a copy of an article. I did some research and found that the Avionics West Review was done by someone who bought a used unit off of another pilot (Not very smart if you are going to write a review on it since you have no idea what condition it is in, you would think they would buy one from the factory??) They took it apart to photograph it obviously. Wonder if this could affect performance if someone who doesn’t work for their company takes a screw driver to it? I wouldn’t put much faith in that article, especially since the guy sells their competition. It looks to me like they are passing a slam-ad off as a “product review” to get more attention to the brands they DO sell. As far as the Monroy unit, I know both SureCheck and Monroy sent their products to Sporty’s for evalutation. Sporty’s rejected Monroy’s and took SureCheck TPAS to sell through catalog and use in their sweepstakes aircraft.

Here is a copy of the article mentioned…


Collision avoidance and the new era. SureCheck Aviation, Inc. gets the industry talking with its first portable anti-collision product.

Since the 1956 mid air collision between two airliners over the Grand Canyon, the aviation industry has sought an effective way to counter mid air disasters. Efforts to resolve the problem of air traffic collisions and near misses became crucial after a 1978 collision between a single engine aircraft and an airliner on approach to San Diego International airport. Finally in 1986 near Los Angeles Airport, a collision with a private aircraft and a departing airliner, prompted congressional legislation to mandate Traffic Alert/Collision Avoidance Systems in Commercial aircraft.

Modern TCAS is a complex system, which involves manipulation of an existing RADAR system known as “ATCRBS” or secondary RADAR that interrogates your transponder. The system operates by use of many methods, however the way in which general aviation aircraft are “seen” by TCAS is often through interrogation much like existing Ground RADAR facilities have done for years. The difference is the processing of the information once received. This is not as simple as one might expect. There are many problems that exist when multiple aircraft are interrogating multiple transponders. Several years and software upgrades have yielded sometimes reliable, sometimes no so reliable results. The highlights of TCAS are the ability to locate transponder equipped aircraft, range them, differentiate host aircraft to intruding aircraft and display this into useful information to give a pilot independent traffic resolution beyond ATC. Without diving into the vast technical problems engineers faced when coping with multiple transponder replies and RF / microwave behavior with respect to reflection, it is important that pilots know and understand that even the best systems still today have “bugs” which will require technology that is still down the road to come. The good news is, that over time the reliability has become such that pilots today feel safer flying with a TCAS system than without. Now the real problem. Price. A typical installation can easily reach $100,000.00 per unit! So unless you plan on doubling the value of your aircraft for one piece of avionics equipment, this is not a viable option. New versions have emerged in the TCAS market, which have proven less cost prohibitive, and as of today a good active system will run you near $20,000.00 and up. Now this may reach many pilots who feel this price is worth the security for the present technology offered, however to the average pilot, who makes up most of the aircraft flying today, this still is not a realistic option.

So why is TCAS equipment so expensive? The reason is actually simple. Complexity. 90% of the software involved with Collision avoidance equipment is filtering out potential false alerts. The beacon RADAR system, ATCRBS, was not setup to be used as a collision avoidance tool. The other side of the expense is the engineering skills required to design and maintain upgrades are not only rare, but experience required is a must.

With improvements in semiconductor, processors and RF / microwave products, a new era of collision avoidance has entered the market. The TPAS®, designed by SureCheck Aviation, Inc. became the first truly portable, basic collision avoidance system. TPAS stands for Traffic Proximity Alert System. So what is the difference between TCAS and TPAS? Why such a cost difference? As mentioned before, TCAS is an active system, which interrogates other nearby transponders and process information accordingly. The TPAS system eavesdrops on these replies generated by not only TCAS systems, but Ground RADAR facilities as well. Without the need to transmit interrogations, TPAS avoids tremendous costs, and being portable the costs drops even further. But not interrogating other aircraft has its drawbacks. In a non-RADAR environment, where neither TCAS systems are operating, or Ground RADAR facilities are in range, replies cannot be heard. The reason TPAS is viable today however is because of the vast improvements of RADAR installations. Today’s coverage of Beacon RADAR systems is vast and covers even the most remote areas very well with altitude. Some limitations begin to occur when aircraft enter areas well shielded from such facilities, but even these holes continuing to be filled with RADAR services yearly. As mentioned before, TPAS also accepts replies generated by TCAS equipped aircraft, so valleys and shadows can be illuminated by even one aircraft such as an airliner operating at 30,0000 feet overhead. The TPAS system listens for the different kinds of interrogations, such as either ground or TCAS and displays to the user a constant indication of whether he is in a RADAR environment or not. This is one of the most important features, since the accuracy depends on a live RADAR environment, even if slight which one cannot gather from watching a transponder reply light alone. This light although sometimes useful, differs with different brands and in some cases only indicates if a valid signal has been received, not transmitted. In some cases where TCAS is active one may not even see a reply light because it is so short, and without this feature pilots would not know whether or not traffic could be detected. The TPAS system displays Traffic in estimated nautical miles, based on internal computations and variance factors, within 1800 feet of the host aircraft. Aircraft are sorted by priority and displayed accordingly. When an aircraft lands or is no longer a threat, TPAS switches to display the next closest threat. Two modes of operation are another important issue, since aircraft operate in two completely separate regions of potential conflicts. The first being an airport area where density is higher and separations are less. TPAS is designed to recognized potential conflicts and alert the pilot when an intruding aircraft meets criteria suitable for an airport environment. The second mode of operation, enroute, covers the phase of flight where air traffic is at it’s greatest speed and separation distances. The importance of this completely separate mode and alert criteria is to enable the pilot to see aircraft at a further range, up to 10 NM, and allow suitable time for reaction and decisions. Another mode, which serves to protect the receiver and reduce false alerts, is the ground or Standby mode. This keeps high output microwave energy generated by various RADAR or Weather systems from damaging the sensitive circuitry. The drawback of this type of collision avoidance unit is directional information. The concept behind TPAS is to raise traffic awareness to a pilot by acting as a second pair of eyes, eyes that can see around edges and corners and whose sole purpose is to scan for traffic. The addition of directional equipment would not only possibly inhibit portability (thus raising cost significantly) but also require an installation to accommodate various antenna configurations. Although SureCheck Aviation is working hard to produce such technology into a portable product, it proves to be a great challenge. However, with experience and use, pilots who use TPAS many times are able to discern direction based on closure rates. Obviously an aircraft coming towards you from the front will result in a fast closure rate whereas traffic from the rear will tend to “stick” near a mileage point until it slips out of range. Is it worth saving $19,400??? That is up to the user, however for pilots who rent, or do not have a spare $20K, this is by far a good step in the right direction of increasing traffic awareness.

With years of engineering, TPAS yields the following features.

· Completely Self-Contained
· Traffic detection up to 10 NM
· Range selectable, from Terminal (5 NM) to Enroute (10 NM)
· Audible alerts for Traffic Advisories and Traffic Alerts
· Visible warning system similar to TCAS
· High-brightness LED 2-digit display
· Digital range accuracy
· TCAS and Ground Radar Interrogation Indications. Know if you are in a RADAR coverage instantly, or if you are being watched by other aircraft using TCAS
· Auto intensity light for day or night operations
· Adjustable volume and mute
· On-board test function with audible confirmation
· Compact adapter included or 6 AA batteries
· 12 or 28 volt system compatible

I wonder why it would be so difficult for TPAS to give an altitude readout if in fact it can detect a transponder. Maybe I am naive but isn’t the signal with altitude information already on its way to ATC? Boy if they could give altitude and range for about that price! Now you are talking!

A friend of a friend right? Sounds fishy to me. I think posts like that are usually from either sales reps or the companies themselves. If not, save your money. I tried the Monroy gadget and it either gave me constant false traffic, or didn’t work at all. Most of the time it would show 1 dot, then suddenly jump to 3 or 5, then back to nothing then up to 4 all within maybe 7 seconds. It made no sense. My list of complaints grew so long finally I just stopped using it. I wonder if it is so small because it lacks the “brains” needed to make it function with even some consistency. I might install something “proven” in the future, however I am in the meantime stuck with this piece of junk monroy.

The preceding message from “anonymous” has all the earmarks of an advertisement from the manufacturer or one of their employees. I have no opinions about the product under discussion, but I would have questions about a firm that can only advertise their products using free forums and anonymous messages.

I agree wholeheartedly! First, the writer has confused the original “apples and oranges” point. My point was that comparing ground based weather radar data on the AnywhereMap with the “spheric” data from Stormscope was comparing apples and oranges, since they are two completely different sets of data.

As to the traffic collision devices, there are some basic detectors of transponder returns that work. Regardless of the long paragraph of techno-babble, the author seems to be promoting one that doesn’t work.

I have a lot more trust in the review by Avionics West who has taken the time to test a number of categories of products including the basic traffic collision detection systems than in an “anonymous” post that looks like an advertisement.

In essence, if you want the basic traffic collision detection system, there are some out there that work, just not that one.

At the very least, due diligence requires that the basic reading list is: 1. www.aviationconsumer.com
2. www.avionicswest.com
and last, for a somewhat excessive “boosterism” of advertised products:
3. www.avweb.com

And by all means, discount 100% any “anonymous” posts which appear to come from the manufacturer or employees. In fact, after I read the review in Avionics West on the product mentioned in the original post my thought was why doesn’t the Federal Trade Commission get after these people for selling a completely worthless piece of junk!

I find it really odd that you think the Trade Commision should jump in and pounce them just because a possibly biased retailer doesn’t like it. If they did that on every printed opinion about avionics, we wouldn’t have avionics and TCAS would be outlawed. (especially TCAS I) I use it and have no real problems with it, and apparently so does another poster on this board, so I think there is something obviously wrong with the Avionics West issue. Why do you put so much effort into slamming a product you have never used? That is suspicous to me. Anyway, I thought I would put my 2 cents worth in. I bought a tpas unit about 3 months ago from an online store called AvShop.com I had it installed by my avionics shop and use a cable extension over to my right side window just about 5 inches in front of the hinge-bend. Until the market returns and I can plunge into something like a Skywatch, this is a real gem in my cockpit.

As Director of Operations for SureCheck Aviation, I felt the need to personally address the concerns posted here. I try to monitor message boards such as these to see if I can offer assistance or, in this case, help shed light on a hotly debated issue.

First, I am aware of the “review” that was posted by Avionics West. Of course, we welcome any reviews, and if there are problems with our products, we take the appropriate steps to remedy them. Dr. Roger’s article has been reviewed by myself and our avionics team and was found erroneous on many points. A Press Release detailing the errors was sent to all avionics shops that carry SureCheck products, all aviation-related magazines and publications, and posted online at http://www.surecheck.net/PR_010927.html. In response, Dr. Rogers has agreed to fly with me and retest our product. Since I fly regularly with the unit and test it successfully against ATC, I have no doubt the results will be different.

Secondly, the above threaded response entitled “Apples and Oranges”, while appreciated, did not come from our company. We have a considerable budget for advertising, as our ads in AOPA Pilot, Cessna Owner, Piper Magazine, direct-mail campaigns, dealer promotions, and others will attest to. With a network of over 40 avionics shops and 200 pilot supply shops around the world selling TPAS, I think the accusation that we “only advertise using free forums” is a bit out of place.

Last, I urge anyone who is seeking an alternative to more price-inhibitive products to try TPAS for themselves. This is new, cutting-edge technology, and as with any new “gadget”, concerns are bound to come up. I welcome any questions anyone may have. After all, my company’s future depends on providing reliable, useful, life-saving devices. How long do you think we would last if TPAS truly did NOT work as these people are suggesting? A qualified evaluation includes actually using the product for themselves under proper conditions and judging accordingly. As always, I will gladly, personally demonstrate TPAS to anyone flying into the San Diego area. The proper use of such equipment has, and will continue to, save many lives. I stand behind our products, as does the entire team at SureCheck.

Thank you.

Thanks, you gave me my first smile this morning! ME, IN SALES? Anyway, didn’t mean for my post to sound “fishy”. I respect healthy skepticism.
I truly was planning to buy the Monroy. And yes, my friend (the owner of the first SR20 based at KLNK Lincoln, NE) really does like his Monroy.
Your report gives me pause, however, as I have not heard many negatives of either passive unit, and the Monroy is MUCH smaller. Fairly positive write-up by Aviation Consumer as well. Now I don’t know what to do - buy or wait.

Randall Erway
COPA Member
SR20 Position #238
Cirrus Stockholder
Sorry- Not a Sales Guy

P.S. Is your “piece of junk” for sale, maybe? :slight_smile:

I have a Monroy in a C172, Velcroed to the glare shield, with an external antenna. For the dollars invested it is a great tool, especially here in the North East ( Long Island) where ATC is (was) busy enough that they don’t always call out traffic even while IFR or using flight following.
The voice feature I almost always mute within 10 miles of busy airports as it is always calling traffic. Instead I rely on the visual cue of the light bars. The bars took me a while to learn to interpert them so I wouldn’t constantly yank & bank trying to locate traffic that wasn’t really a threat.
The Monroy shows Mode S transponders as a blinking orange light along with the light bars. That means that when the light bars immediately go from no bars illuminated to 5 bars lit, it probably is not a real threat because the closure rate is faster than most G/A planes. When the bars illuminate to 3 then 4 and then hold steady, I’m pretty sure that the target is slowly getting closer but is probably parralleling or approaching slowly on a tangent - look, but don’t go crazy.
When the bars go from one to five over a few minutes, I am looking intensely and most times spot the traffic even if ATC is silent. Sometimes I never see it even if I know it’s out there & pretty close, but then again I never see a lot of what ATC does call. I rode in a C210 with the Ryan Tcad and was amazed at the amount of traffic showing the 1) ATC never mentioned and 2) couldn’t find even though we knew rough direction and altitude
Depending on antenna location, or using just the “rubber ducky” that comes with the unit, aircraft can get fairly close without either bars lit or voice activated. However, I have NEVER seen a plane closer than about 1-2 miles in any direction without it showing on the unit.
The drawbacks -
It takes time to get used to it & learn to use it properly
It doesn’t show non transponder equipped a/c or those with inoperative or non turned on units, but nor do the 25K units
Its veil, so to speak, is supposed to be 1500’ above/below, within a 5 mile radius. It does NOT give any clues to direction or altitude.
cheap - mine was $895 though they are a little less now
Makes you get you head out of the cockpit and put it where it belongs - outside
portable - if you rent you can take it home at night
Peace of mind for my wife concerning mid airs ( I forget to tell her of its limitations).
Everything being said, I am happy I have mine and can count at least 5 - 6 instances where I was VERY HAPPY to have had it on. I wouldn’d put it in the Cirrus only becuse I want the Skywatch and its expanded capabilities

John Dolan #476

Assume they just read signal strength and use that to calculate distance. Same as TCAS, I believe.

So, they’d need to read the digital grey-code the mode-c transmits. Not rocket science, but few more chips.


Actually it may well be rocket science - I thought the same as you until I found out more about the encoding used in transponder replies. The problem is this; a transponder can give two kinds of replies; one (the mode A response) gives the squawk code, encoded as a 12 bit number. The other response gives the mode C altitude readout, also as a 12 bit number. However, there is no inherent (or as the techies would say, “in-band”) way to distinguish one kind of reply from another. The ATC radar and active TCAS can, because they sent a particular interrogation - i.e. they asked the question, so they know which answer to expect.

The passive TCAD systems only hear the answers, not the questions, so they can’t tell whether the data they are seeing is squawk code or altitude.

The company has indicated that they are working on an altitude readout addition (no release date yet). They also will be offering an upgrade program to current owners. Now that will be something when available!


Thanks - that was a thoughtful and very useful post!