Original antenna of RFXtrx433 actually quite small

[jjnj]

The Best:
http://www.ebay.com/itm/181634223889?_t ... EBIDX%3AIT

Give some money.......

Just received it, damn it's big and heavy! Gives a very good signal and the long cable comes in hand.

[Derik]

damn it's big and heavy! Gives a very good signal and the long cable comes in hand.

[PABben]

I'm still in the search for the best antenne and i'm sharing what i've tried.

I also have a tellstick and using the "Conrad 433"-antenna i have great range. I have about 200m2 and from my antenna to my WTH450H (wich is said to have a very short range) there is 6 wooden walls and approx 10 meters. Never missed a reading...

With my rfxcom i onnected the conrad-antenna and i lost readings of devices only 3-4 meters away. The strange thing was that readings from devices in a horisontal line from the antenna where good, but devices that are 45 degrees below, didnt work.
I tried to connect a aerial amplifier between the rfxcom and the conrad, but only a slightly better range.
With the "Ham Radio" the range was even worse.

At the moment i tried the original antenna and it's way better than the other two! However, i don't understand why? Any ideas?

Conrad-antenna: http://www.conrad.com/ce/en/product/190 ... sembly-kit
Ham Radio-antenna: http://www.ebay.com/itm/433Mhz-5DBI-GSM ... 2eccdec506

[sincze]

The Best:
http://www.ebay.com/itm/181634223889?_t ... EBIDX%3AIT

Give some money.......

wow looks promissing. I'll follow this thread.

Currently using
http://www.ebay.com/itm/433Mhz-5DBI-GSM ... 2eccdec506

Is a significant Improvement over my original antenna, however still not enough to cover my complete house (a lot of concrete floors).

Soldering 17 cm of installatiedraad looks to be the most cost effective way.

[Minglarn]

I'm still in the search for the best antenne and i'm sharing what i've tried.

I also have a tellstick and using the "Conrad 433"-antenna i have great range. I have about 200m2 and from my antenna to my WTH450H (wich is said to have a very short range) there is 6 wooden walls and approx 10 meters. Never missed a reading...

With my rfxcom i onnected the conrad-antenna and i lost readings of devices only 3-4 meters away. The strange thing was that readings from devices in a horisontal line from the antenna where good, but devices that are 45 degrees below, didnt work.
I tried to connect a aerial amplifier between the rfxcom and the conrad, but only a slightly better range.
With the "Ham Radio" the range was even worse.

At the moment i tried the original antenna and it's way better than the other two! However, i don't understand why? Any ideas?

Conrad-antenna: http://www.conrad.com/ce/en/product/190 ... sembly-kit
Ham Radio-antenna: http://www.ebay.com/itm/433Mhz-5DBI-GSM ... 2eccdec506

Interesting! I too have moved on from the tellstick to RFXtrx and have exactly the same Conrad antenna and one NAGOYA NA-701 antenna connected to my DUO.
I tried both antennas to my RFXtrx and the range dropped to nearly ZERO. Dont know why but the original antenna seems way better...
I will order a http://www.ebay.com/itm/181634223889?_t ... EBIDX%3AIT and see if the range gets any better..

[sincze]

Interesting! I too have moved on from the tellstick to RFXCom and have exactly the same Conrad antenna and one NAGOYA NA-701 antenna connected to my DUO.
I tried both antennas to my RFXCom and the range dropped to nearly ZERO. Dont know why but the original antenna seems way better...
I will order a http://www.ebay.com/itm/181634223889?_t ... EBIDX%3AIT and see if the range gets any better..

Keep us informed I ordered the cheap soldering one just to get the old soldering iron out of the box.

[sincze]

Started soldering. However did not change that much.
viewtopic.php?f=44&t=3542&start=60#p57646

[PABben]

Interesting! I too have moved on from the tellstick to RFXtrx and have exactly the same Conrad antenna and one NAGOYA NA-701 antenna connected to my DUO.
I tried both antennas to my RFXtrx and the range dropped to nearly ZERO. Dont know why but the original antenna seems way better...
I will order a http://www.ebay.com/itm/181634223889?_t ... EBIDX%3AIT and see if the range gets any better..

Have you tried this one yet?

[sincze]

Yes I would also be interested in the results of

This one
http://www.ebay.com/itm/181634223889?_t ... EBIDX%3AIT

over the one I'm using now:
http://www.ebay.com/itm/Ham-Radio-5DBI- ... SwYHxWOXhS

[PABben]

This might be a bit off-topic but hopefully it is to use for someone else so i'll post it anyway:

I just spoke to rfxcom and they had a good point: If there is RF-noise, the noise will also be amplified using a antenna. In my case the range is shorter with a better antenna so this probably is the cause. Also, tellstick is using a different reciever and therefore might not be affected by the same noise.

Examples of things making RF noise: Bad power supply, Rasberry PI, certain sensors (low battery or water inside the device etc.)

I have ordered a RF reciever and will use "airspy" to see the RF noise. Here is a guide to set up your own (10$ of equipment needed). It's in norwegian but send me a PM if you need translation.
http://old.telldus.com/forum/viewtopic.php?f=2&t=5094

EDIT: updated link

[PABben]

Sorry for bumping but just discovered that the RF noise was from the network switch. It seems that RFXcom is more sensitive to network cables and switches noise than tellstick.
Moved my server to another room and with the original small antenna i now get readings from these temp sensor (who is supposed to have a bad range) 10 meters and 6 walls away: viewtopic.php?f=17&t=10227&p=81049&hili ... las#p81049

Adding a larger antenna (conrad 433) made the range even better (not worse, as it did when having the antenna in the other room)

So, if you're having issues with missing readings and range, try to put the rfxcom/antenna as far away from network equipment as possible

[xAPPO]

The strange thing was that readings from devices in a horisontal line from the antenna where good, but devices that are 45 degrees below, didnt work.

Single elelement vertical antenna with increased gain like the 10dB quoted for one of those eBay auctions mentioned above typically achieve this by becoming more directional in reception (and transmission). They effectively squash the radio signal vertically making it more sensitive to signals at right angles I.e. on the same level (floor) but less sensitive to off axis signals - say those at 45 degrees coming from another floor above or below. Of course signals can bounce about and reflect off many objects.

A full wavelength at 434 Mhz is approx 70cm so the suggested lengths are quarter waves. Antenna length can improve the gain of an antenna but the omnidirectional fancier ones also change (flatten) the radiation pattern - which is typically what is useful for distance reception. You can also create highly tuned antenna which reject slightly off frequency signals which all helps in the the later selectivity filtering. Eliminating unwanted noise will work wonders for better reception.

[Stokie21]

would this one be any good?


http://www.ebay.com/itm/433MHZ-35dBi-SM ... SwFdtX17Mq


Say 35DB

[b_weijenberg]

I guess they forgot to put a decimal point;-)
This 3dBi antenna improves the range: http://www.ebay.com/itm/GSM-GPRS-Antenn ... 0985451637
Install this antenna on a 30cm metal plate for the best result

[Stokie21]

I guess they forgot to put a decimal point;-)
This 3dBi antenna improves the range: http://www.ebay.com/itm/GSM-GPRS-Antenn ... 0985451637
Install this antenna on a 30cm metal plate for the best result

i ordered one of these, but then i seen the one i posted above and wondered if that would be even better

[Wirehead]

Bumping this one, always wondered about this antenna's performance. Here's an S11 measurement of the stock RFXcom antenna. Out of tune. It will work, but there's a lot of return loss and it seems to be tuned higher. SWR at 433MHz is 5.6:1

swr_rfxcom.png (131.7 KiB) Viewed 5002 times

[tweakertje]

I m reading this topic and tried to make tje 17.3 cm antenna WHOW that changes a lot but when reading there raises an question
Does it make anny diffrance to use a 433mhz bandpass filter to reduce noise fron pc switches etc.

Im thinking about this one
http://m.ebay.com/itm/331969186194

Verstuurd vanaf mijn SM-G930F met Tapatalk

[tweakertje]

I m reading this topic and tried to make tje 17.3 cm antenna WHOW that changes a lot but when reading there raises an question
Does it make anny diffrance to use a 433mhz bandpass filter to reduce noise fron pc switches etc.

Im thinking about this one
http://m.ebay.com/itm/331969186194

Verstuurd vanaf mijn SM-G930F met Tapatalk

Does annyone knows???

Verstuurd vanaf mijn SM-G930F met Tapatalk

[b_weijenberg]

The RFXtrx has already a bandpass filter for 433MHz. But RF noise produced by digital circuits can also transmit at 433MHz and these signals are not blocked by a bandpass filter.

[Fleshi]

Sorry to give this topic a bumb, but I' am also looking for another antenna.

When looking a this topic I see different variants. Can somebody tell me out of his own experiences which is the best?