Ghost Tags and Dropping Out

[The Gemini]

One other thought to consider...the 40m Transmitters are VERY strong transmitters and can actually saturate the receiver if they are used inside of the house/garage, etc. This is because the RF Signal bounces around off of walls, etc. I have had only 8m transmitters running for months now and it works great...I have a 40m in my wifes car, but it is outside and not in the garage. I might try putting a 40m in my car which is in the garage and see if that causes dropouts...

I'll check on the timeout value again...I thought I had that fixed but maybe not.

Thanks.. your efforts are appreciated!

[Pete]

PiperPilot, can you put up a drawing depicting the best spots to solder an RG6 connection to the RFID reciever? I wired my center lead to where the pigtail antenna was and the ground to the main board ground (think it was the ground?). I am thinking of taking my antenna off of the RFID Reciever in the garage to make a smaller footprint and making it more pleasing to the eye. It seems that the RFID reciever mounted in the attic with its pig tail antenna works fine. I am thinking of going back to the little pigtail antenna in the one in the garage. The Honda (sitting right about 10 or so from the RFID) works fine. The BMW and the Mazda continue to drop out with the 40M tags. The 8M tag though works both in the Mazda and the BMW. Would there ever be a thought of making an 8M tag with a 12V terminal strip on it? I guess I could just velcro it to the windshield.

[piperpilot]

Sure thing...I'm on the road today...but I'll take a picture tonight and piont out the best spot for ground.

As far as an 8m with terminal block...hmmm...the hardware in the two devices is almost identical, it is just a power output setting...maybe I can figure out an easy way to lower the power out put on the existing 40m...lemme work on it.

PiperPilot

[Pete]

Thanks Piperpilot....not sure if my issues are due to too much RF or not enough. All three cars have the 40M RFID mounted in the headliner adjacent to the map light. The Mazda is outside and works 98% of the time while the BMW is on the far side of the 3 car garage and works 50% of the time. The 8M RFID works well when its in either of the the two vehicles with no problems. The Honda with its 40M RFID tag works 100% of the time but it is sitting about 10 feet from the RFID reciever.

[piperpilot]

Maybe the Honda is saturating the receiver? That would be my guess...

Also, keep in mind that RF doesn't really like metal...so the closer you install to metal objects, the more the signal weill be absorbed, distorted or bounced around. I tried to put on on my garage door with a mercury switch and never could get it reliable because of the metal...but same transmitter 6 inches from the door held in my hand worked great every time.

[Uncle Michael]

One other thought to consider...the 40m Transmitters are VERY strong transmitters and can actually saturate the receiver if they are used inside of the house/garage, etc. This is because the RF Signal bounces around off of walls, etc. I have had only 8m transmitters running for months now and it works great...I have a 40m in my wifes car, but it is outside and not in the garage. I might try putting a 40m in my car which is in the garage and see if that causes dropouts...

This may be way off, but...

What is the nature of the anti-collision algorithm? I'm guessing it does not prevent communication loss from saturation, but I thought the transmitters were on for only a brief time. How long does the saturation effect last?

If the anti-collision is a slight timing difference in the interval between transmissions of each tag, is it possible for those frequencies to 'beat' with one another, occasionally causing two tags to transmit at approximately the same time for several successive transmit events?

[Bill Brower]

Hopefully Piper will chime in if I'm wrong but the only anti-collision I see is the very quick burst with respect to how often it transmits.

[Bill Brower]

The issue probably is oversaturation due to the design (and benefits) of superhetrodyne receivers.

If there is a strong signal the receiver cranks back the gain, thus perimeter or less strong tags may suffer.

I found on my wife's Honda that the keyless entry is a similar setup.

When the wife parked near the receiver all the other tags outside dropped out.

The solution to vehicles too close to the receiver is switch to an 8m xmtr or shorten the antenna.

The 40m xmtr actually kepy the wife's keyless entry from working until I downsized her 40m xmtr to an 8m one.

[Pete]

Great learning experience! Going to try to first remove antenna from 40M in headliner of Honda and just use a small pigtail to see what happens. I would like to keep it unobtrusive as the "old" eagle eye didn't meet WAF and floated around a bit in my wife's Honda. Out of the three cars only the Honda has screws holding the map light in place, so its a bit more time consuming to play with. I would like to keep from having to change the battery if possible.

[The Gemini]

Well, a new twist on my set up. I have (had) a 40M in my car, a key fob in my wifes car, and another key fob sitting stationary for several days. I have had constant and unacceptable lengthy drops outs from the key fobs since I first got them. Monday afternoon I noticed that my 40M had dropped out and was no longer transmitting. Replaced the chip and check the batteries and it started to work again for about twenty minutes then quit again. I removed the batteries and set it aside until the weekend when I would have time to fault trace it.
The following days I realized the key fobs were not dropping out AT ALL. So maybe this saturation theory might be more fact than theory.?

[Bill Brower]

So maybe this saturation theory might be more fact than theory.?

It is a fact.

Take the car with a working 40m and park it outside, the key fobs will become steady.

I suggest you shutdown the plugin and start watching Hyperterminal as a troubleshooting and configuration aid.

[Pete]

I have removed the little antenna from the 40M tag in the Honda and back to the pigtail on the garage reciever. Checked the Mazda 40M tag as I still didn't see it. Took it inside of the house and connected it to my "test" AC/DC 12VDC 200 Mw adaptor. It still does not work. Not sure why. My test tag is working fine. Took a key FOB tag into the Mazda - it is seen a bit outside of the house.

[The Gemini]

I have removed the little antenna from the 40M tag in the Honda and back to the pigtail on the garage reciever. Checked the Mazda 40M tag as I still didn't see it. Took it inside of the house and connected it to my "test" AC/DC 12VDC 200 Mw adaptor. It still does not work. Not sure why. My test tag is working fine. Took a key FOB tag into the Mazda - it is seen a bit outside of the house.

My 40M quit also.I had a couple of extra firmware chips that I got from Piper when I ordered my stuff.
I installed a fresh chip and it worked again for about 20 minutes and died again. Change the chip again with another and it has been fine since.
Got any extra transmitter chips to try??

[Pete]

I have 2 other 40M tags. Will give it a try. Thank you Gemini.

[ka7gzr]

Sounds like the receiver has an AGC (Automatic Gain Control). This lowers the gain of the front end of the receiver so that it doesn't become saturated in the presence of a strong signal. A very common feature of receivers. It will cause loss of weaker signals. AGC's have "attack" times meaning how fast they control the gain of the receiver. With many devices transmitting randomly and varies received signal strengths coupled with the receiver's AGC attack time you can image would could happen (dropouts).
Jim
KA7GZR