Workaround for no numbers showing up on the Dexcom

I found a little workaround for when no numbers show up on my Dex, even though it is within range of my sensor, so I thought I'd share (I searched and did not see anything like this already posted here).

Occasionally, for no apparent reason, I get the "Out of Range Antenna" icon in the upper right of my Dex, even though my Dex is within range (usually it's in my pants pocket). There is no number because of this apparent disconnect, however I found a way to get at the current number:

1. Click the OK button
2. Arrow down to "Enter BG" and hit OK again as if you are entering a new BG number

The number shown by default there when you do this is your current BG number!

3. Hit the RED button on the right to exit (DO NOT hit OK or it will actually enter this BG number for you as if you pin pricked to get it, and you don't want to do that here)

A moment or two upon exiting and going back to the graph, the normal antenna appears in the lower right, and the number shown you via the workaround is shown in the upper right as your current BG level.

This seems to work every time for me, though YMMV.


Good to know. Thanks Michael.


This is interesting. I've noticed this, but thought it was just the last bg that it had recorded. You have found that not to be the case?

But Michael, every time I do get an out of range, when the Dex is close, it is only for one reading anyway.

It will always read the next reading.

So, is it possible that your trick does not really do anything?

And Dex is close enough to read the next transmission anyway?


>> the last bg that it had recorded

As in the last one it recorded before it went on the blink? I can't go back in time to check on that on the unit itself, so not completely sure. All I know is that if I get the Out of Range Antenna, then I have no number, but if I follow the process above, I get a number. Perhaps I am just kick-starting the Dex to reconnect. In any case, thereafter I get a number and am back on track.


Mine checks out for a while, certainly more than one reading sometimes. When I look at the dots, it appears it can disconnect for what look like 15 or 20 minutes sometimes. If I follow the above process, I get back on track pretty quickly (see my reply to Lorraine, above).


You bet.


Nice one!

I recently discovered the same thing. I think it's showing the last number that it had 'calculated' before going out of range. If you go to the 1 hour screen, you can get an idea of how many 'dots' are missing, and how long ago the last reading was. Each dot is 5 minutes apart when none are missing.

In my case, I discovered it when I really did want to enter a BG ! I knew that it had 'alerted' me to enter BG, but it was a while before I got to it. After doing the meter check, I picked up the dexcom, and saw it was out of range. But decided to enter it anyway, and was surprised !

That's quite possible. As mentioned earlier, I may just be kickstarting the Dex. But, it seems to work as the numbers don't really deviate a heckuva lot from that initial number after it gets rolling again. You might imagine that if you were at 115 the last time it registered a number, but ascending, that you might be much higher later when it reconnects. I am not seeing that: if it shows 115 via the process above, the next number is usually pretty close to that initial number for me.

It's all quite inexact in any case. I just thought this might help folks if they see that out of range antenna a lot.


This is excellent comment and articles.

I also use the approach suggested and find it helps but not always.

I have found many times some idiot interferor-trasmitter/servor is hammering my receiver/trasmitter as I walk out of my condo across street and I will see link recover immediately.

When I catch the creep causing this interference I will have their equipment and butt arrested for interfering with my medical condition.

Funny part is I do not see this nonsense when in my metal car and when driving up 395 behind the mountains in california.

I always move if I am having problems. If the steps recommended using bg key here do not hook back up in 5 minutes, I immediately move a few thousand feet out of my condo and unit re-hooks up without any more hastle.

Last sunday in am, I was resetting my sensor after less than 7 days and kept getting the dread ???. I went up between the valleys of the mountains on the coast here in california and the unit ran thru 2 hour re-init without incident. Funny how the crap surfaced on the 7 day running zone sitting in my condo.

Mine has done this too. The gap in dots shows that it's about 15 or 20 minutes. I usually have mine in my pocket also.

What sort of equipment/technology do you think is interfering with your receiver? I also live in Southern California.

I thank everybody sharing their personal experiences.

From a technical perspective; these transceiver technologies are compact IC based and they have two issues with interferor's.

a) the interfering equipment is on your same frequency and high enough power to jam.

b) the interfering equipment simply high enough power regardless of frequency to overwhelm receiver and its rejection capability and overwhelm it. I believe many cases are like this.

One time was real nasty when I was in my dentist's offfice ( been there a number of times without incident) and my receiver went out of range. It did not connect till I walked out of this medical building and hopped into my car - metal and it immediately re-connected. Diathermy machine - RF heater, this was medical building.

I have had so many cases sitting in my condo with my unit 1 to 2 feet away as others here have noticed and seen it disconnect for no apparent reason. It would not re-connect till I went outside across street and it immediatly re-connected.

I have a small solid state RF meter that I have scanned my condo(5 unit set of a townhouse building unit) and have caught burglar alarms, servers presence. Without about $ 12K of RF spectrum analyzer and directional antenna - tracking the nuisance factor is extremely diffficult.

Checking the 400 megahertz band on web for uses and I see military has some equipment and channels in or very near to 400 megahertz band that is also used by low energy medical non licenced connection equipment used for insulin pumps, Dexcom, etc.

I really belive these links should have encryption with user supplied key as well as more robust reporting on connection status and interference. Presence status reporting is totally shameless and next to none.

The funny part is that sitting in my car driving for 5 hours up in backwoods - Bishop California, drving across LA, result in far less disconnects and issues than living in my condo in Camarillo.

Last Sunday, on day 7 of operation after week of running stable, I see my Dexcom at 7:00 am read crazy readings - drops to 100 and flatlines and then later goes to the dred ???. I walk outside it reconnects and starts back up with great readings and I let it run for an hour. I then do a stop and restart to get a few days more and sensor goes ???. Woud not clear till stopped and restarted.

I left same sensor in and drove off site for 2 hours in the back weeds of here in some local mountain canyons and sensor completes a restart without incident and starts backup reading fine. I go back to my condo and the sensor drops out again after awhile with ???.

I did get it to clear and come back on with rational readings; but decided to swap in a new sensor.

Maybe I need to line the inside of my condo with fine copper mesh to block the nonsense.

Thanks for the detailed analysis jim. I'm an engineer myself and enjoy learning more about these sort of issues at a deeper scientific level.

Hey, it worked! Thanks Michael ;)

THis issue of no numbers and the dreaded ??? gets more curious:

This story gets more curious, the more I delve into.

I was finding in last months, that the appearance that my sensors were dropping out due to failing exactly 7 days - mostly ??? !

the more I checked , I found that no, sensors were still functioning correctly as long as I got out of my condo a 100 feet and found receiver would recover after about 30 minutes and then accurate readings would come back on . As long as I stayed out of my condo, receiver and old sensor started working fine again.

I also found that while in my condo when the fun erupted - readings dropped to 100 at speeds that body cannot do, if I walked out of condo, and got away from my condo, I would see the following:

a) receiver would go to ???. Antenna status would disconnect and then reconnect.

b) While out of condo, I would cause a disconnect of receiver and then let it recover and stayed away till back up.

c) amazingly now 3 weeks later and multi-times , I have repeated this nonsense and recovered the sensor/receiver pair and got accurate readings.

d) after recovery, during this interval of interference in my condo, as long as I kept my receiver in my car trunk/ refrigerator and took out when I left my condo, there was no problems with it on old timed out sensor(restarted)

I find this all very unacceptable, intolerable.

My sense is that:

Some interfering RF signal close by in my unit was emitting sufficient power to override my sensor/transmitter pair.

Some how my receiver was loading incorrect erroneous data causing drop to 100. I would see the antenna staus on receiver suddenly disconnect for no known reason and if I walked outside away from unit, it would re-connect properly and run.

When I walked out of my condo and got far enough away from interferer, my receiver would see valid restored reading of my transmitter that was way different from previous garbage loaded in my condo and declared the sensor bad ???.

Staying out of range of interferor, allowed the receiver to recover and then go back and display correct data. ( About 1/2 hour.)

Is this acceptable - no!

One thing driving me nuts is why this crap goes on in my 6 unit condo site while in fact out of here, performance is actually fine for a rf linked device, outside up by condo lot swimming pool, in car, driving around, in the mountains around here near the beach.

I have even walked around my 6 set townhouse-condo building with an excellent rf field meter set and find that looking out from our building set, I see little and mostly quiet, but looking into our building set I see high energy leakage that shouldn't be there.

The other curiosity was that if I caught a fast drop just as it started by walking out, receiver sensor pair would immediately recover back to path it had been on and continue fine with no ??? . I would also see an antenna status change although receiver had been within 2 feet.

I do not know how the rest of you good folks cope with this kind of grief?