Wh1081 "Lost Sensor Contact"

[Orion]

Hi
I know virtually nothing about radio but over various threads people have suggested many causes and remedies and it still seems to happen randomly so - just a thought - could it be that the frequency of the transmitter is drifting. Maybe a radio expert will know if it is possible.
Regards
Alan

crystal transmitters do drift a little with age and temperature

going back to Timfy`s post impedance matching would be difficult on a FO transmitter, but as it only puts out very low power in short bursts I would not think that the output transistor would have time to get hot enough to blow
weather or not using a dipole or similar antenna would help is very much open to experiment
its a long time since i passed my amateur radio exam (G8XTO)
http://www.rfm.com/corp/appdata/antenna.pdf

[werribee_au]

Has anyone tried improving the antenna used
I think something like this could be used to increase the range of the transmitter with a small modification.
http://www.simplesolutions-uk.com/produ ... 0%9D-cable

This dipole is 166mm which seems a little strange to me as a half wave dipole for 433Mhz is 345mm.
It wouldn't have the same gain as one of the correct dimensions.

A 166mm half wave dipole would be resonant at around 900Mhz.

Another thing is the attenuation of the cable, loss increases as frequency increases.

At 440Mhz the attenuation factor of RG-174 coaxial cable is 25dB/100 feet, quite high.
As the transmitter has such low power the effective radiation of the signal may be even less than what it is without an external antenna taking into account this loss and the smaller size of the antenna.

Just my 2 bobs worth

[wxchaser_04]

Yes! Just after I got my station, after about a week, I lost sensor contact, twice. After checking it out , I found that the contacts of the batteries were not making good contact, so I pried them out making the batteries a bit more snug.
Now the sensors work fine. Good luck.

[Gus]

Hi from a newbie.
Just got a N96FY, and set it up on a photographic tripod in the garden to try it out. Everything was perfect, until the unit blew over in last night's storm..... OOOPS!!!
The batteries popped out, so I put them back, but the two units wouldn't sync. The transmitter led was flashing, so I thought the aerial might be damaged. I was just getting my hacksaw and soldering iron out, when I found your site, and saw Steve's tip about fitting the transmitter batteries before the base unit.... Bingo... Problem solved, thanks Steve!

Gus

[Mace]

Hi, in the just over the week I have had my N96FY I have twice had the "Lost sensor contact" the first time I was only aware after. However it happened again this morning and the display just had _ _ for the external readings. I moved the display closer to the sensor but still no readings, I did notice however that on the display to the top right of the OUT RH, about every 48 seconds a small icon lit up. Does this indicate that the display is actually receiving data from the sensors, I can find no mention of it in the admittedly basic instructions. If it is receiving data then it would sugest to me that it is not a problem with the wireless link but the actual data itself.

[wxchaser_04]

Myself, I have lost my outdoor sensors twice since I had my wireless station and after playing around, I found that the contacts within the battery holder was nominal, but the contacts had to be re-adjusted slighty. and then instead of regular batteries, I got the rechargable ones.
But if your running with the regular batteries, I have wrapped a little bit of electrical tape around my batteries with the temps I have here, in New York.

[Super-T]

Rechargeables won't last as long as they have a built in drain and will go flat with no load at all. Also they are nominally 1.2 volts each.
I just use standard Alkaline but there again I don't live in your temperatures
My batteries I run for a year and then change them.....not flat but avoids problems later.

[Gina]

Lithium cells are best for lengevity particularly with low temperatures. You can get AA size at 1.5v as required.

[Gina]

Looks like my transmitter has failed - put in fresh lithiums and still no signal or even red LED after replacing batteries. So I'll have to find my 2nd tx unit and swap them over while I see if I can fix the faulty one. I've got enough to do without an extra fault-finding session! I see it made a big groan when it died and cried buckets of imaginary rain!!!

[mcrossley]

Has anyone tried the 3V lithium photo batteries. Would their characteristics be better than the alkalines?

[Gina]

I wondered that. Very low, intermittent current should be OK for a CR2032. I might try it - I've got plenty.

BTW, as soon as I'd found my other tx unit and taken it outdoors to the Stevenson box to swap it, I noticed the red LED on the one in use was flashing now! So I went back indoors and both consoles were now showing outdoor readings. Magic!!

[mcrossley]

I was thinking something more like a CR2 - if it will fit in the battery box.

My original no-name alkalines are still going strong after 14 months.

[studebaker]

This happens to me as well. I have determined that it is my cordless phone, when in use, that is the problem.

[Gina]

Our cordless phones, in the UK, work at a much higher frequency and don't interfere.