Help identifying Antenna on RF receiver

[kneegrow]

I am attempting to add an external antenna to my wireless keyboard/mouse receiver in order to increase range. I have found what looks like an antenna printed onto the PCB, but it's apparently not hooked up to anything. I have a few high res pictures to share. can anyone shed some light here? I'm going crazy....I need to find the point to solder the antenna

 

[(*steve*)]

Some of your text is too small to read, however that trace which loops around a few times is the antenna.

If the other connector is connected directly to the same place that the loop antenna is (it's hard to say) then it may be a place to attach an external antenna.

The length of a suitable antenna depends on the frequency. From the look of it, this unit is not bluetooth, and appears to be operating on a much lower frequency.

 

[kneegrow]

Some of your text is too small to read, however that trace which loops around a few times is the antenna.

If the other connector is connected directly to the same place that the loop antenna is (it's hard to say) then it may be a place to attach an external antenna.

The length of a suitable antenna depends on the frequency. From the look of it, this unit is not bluetooth, and appears to be operating on a much lower frequency.

You're right about the low frequency (27.00 Mhz) I'll edit the text to be readable if you'll have another look. I have looked and looked and only found the traces that connect to the ends of the antenna by holding the board up to the light to see some traces below the surface.




EDIT: Text in pictures has been edited

 

[(*steve*)]

OK, 27MHz. You're probably not going to have enough room for a 1/4 wave antenna

We have some members who are far better at RF stuff than I, but I would imagine that a random length antenna would be better than that small loop.

 

[kneegrow]

OK, 27MHz. You're probably not going to have enough room for a 1/4 wave antenna

We have some members who are far better at RF stuff than I, but I would imagine that a random length antenna would be better than that small loop.

Yeah, the proper length antenna would be 8ft. 7 - 31/32in... Not going to have the room for sure, although as you said I think anything would be better than that small loop. and it is TINY, maybe half the size of a postage stamp...


I'll be using an antenna from an old wireless router

 

[MattyMatt]

One thing you could try, is find out how long this trace is (as accurately as possible), and make a wire antenna out of some stranded copper wire (maybe 20 AWG or so?) and see if that works a little better... I'm no RF technician, but I dabble a bit in radio technology.

 

[davenn]

I doubt that its for 27MHz. there isnt enough bandwidth there for hi speed data.
2.4 or 5.8 GHz are the norm. 2.4 being the first band used.

At 2.4GHz you only need a few cm's of wire for a 1/4 wave whip.
realistically... what sort of distance are you trying to get out of the router ?
They are designed for ~ 20metres give or take a bit depending on the type of building they are in etc..

In the open air and a decent directional antenna ... a dish or yagi .... you can get up to 10 km

cheers
Dave

 

[kneegrow]

One thing you could try, is find out how long this trace is (as accurately as possible), and make a wire antenna out of some stranded copper wire (maybe 20 AWG or so?) and see if that works a little better... I'm no RF technician, but I dabble a bit in radio technology.

That's a great idea, guess I'll need a dial caliper..... I still need to find the point to solder it to though

 

[kneegrow]

I doubt that its for 27MHz. there isnt enough bandwidth there for hi speed data.
2.4 or 5.8 GHz are the norm. 2.4 being the first band used.

At 2.4GHz you only need a few cm's of wire for a 1/4 wave whip.
realistically... what sort of distance are you trying to get out of the router ?
They are designed for ~ 20metres give or take a bit depending on the type of building they are in etc..

In the open air and a decent directional antenna ... a dish or yagi .... you can get up to 10 km

cheers
Dave

Thank's for your reply, although it isn't a router I'm trying to modify. What you are looking at is a wireless receiver for a logitech model Y-R0002 keyboard and mouse, which according to the specs operates at 27 Mhz. I was going to use a tiny wireless router antenna that I salvaged because I figured even it would be better than the onboard one...I really don't know though because it's 7/8" long I think and 27 Mhz needs an 8" one. Makes me wonder why they would even make things like this operate at such a low frequency

 

[davenn]

you might want to read the FCC compliance statement for that device

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.

Any changes or modification not expressly approved by the party responsible for compliance could void the user's authority to operate the device. Where shielded interface cables have been provided with the product or specified additional components or accessories elsewhere defined to be used with the installation of the product, they must be used in order to ensure compliance with FCC regulations.

 

[davenn]

is it this one ? .... Logitech Wireless Combo MK260, keyboard and mouse

 

[kneegrow]

you might want to read the FCC compliance statement for that device

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.

Any changes or modification not expressly approved by the party responsible for compliance could void the user's authority to operate the device. Where shielded interface cables have been provided with the product or specified additional components or accessories elsewhere defined to be used with the installation of the product, they must be used in order to ensure compliance with FCC regulations.

Davenn....You're breaking my balls How can having a bigger arial on the RECEIVER cause interference??? but for real, I think suggestion 2 "Increase the separation between the equipment and receiver. " is the issue, although I don't understand why. I mean, obviously I need Bluetooth so I can go anywhere in the house and stop bitching about my 27 Mhz one which usually works fairly well within the designed 6' range.

 

[kneegrow]

is it this one ? .... Logitech Wireless Combo MK260, keyboard and mouse

No it's the MK300 Here:http://www.google.com/products/cata...=X&ei=RuysTebjFsriiAL0-tnfDA&ved=0CFIQ8wIwAA#

 

[davenn]

well then just dangle a 6 ft length of wire out of the receiver it doesnt matter a stuff

take it off either your hole 1 or hole 2


I still suspect its 2.4 GHz as with their other wireless kybrd units, I have seen nothing in any datasheets yet to tell me its 27 MHz .... do you have a link to that ?

Dave

from their www site...

Logitech Wireless Desktop® MK300
For the best-of-the-best wireless connection, Logitech® Advanced 2.4 GHz wireless gives you the reliability of a cord with cordless convenience and freedom. Advanced 2.4 GHz wireless virtually eliminates delays and dropouts—even in the busiest wireless environments, such as a high-tech office.

In addition, Advanced 2.4 GHz wireless is designed to optimize battery power. (Many of our keyboards with Advanced 2.4 GHz wireless can offer up to three years of battery life.)

Your keyboard is automatically paired with your computer. So, you can use your keyboard with the most demanding applications and know that every keystroke you make will be carried out instantaneously. It uses less battery power than other wireless technologies, too

Check out all of our Advanced 2.4 GHz wireless keyboards.

 

[kneegrow]

well then just dangle a 6 ft length of wire out of the receiver it doesnt matter a stuff

Thanks Davenn, I'll just add it to here at the end.

 

[kneegrow]

How can I make an 8' antenna smaller without losing all the benefit of the longer antenna wire? what will happen if I loop it into a coil to make it fit inside the pc case or wrap it around a ferrite core?

 

[davenn]

How can I make an 8' antenna smaller without losing all the benefit of the longer antenna wire? what will happen if I loop it into a coil to make it fit inside the pc case or wrap it around a ferrite core?

it aint gonna work.... inside the PC case its going to be shielded by the case and be even worse than the existing PCB antenna. winding onto a ferrite core is just going to produce a basic RF choke and thats going to defeat the purpose as well.

you didnt answer my Q as to why you think its 27MHz where did you get that info from
when I posted info from the logitech site that pretty much said its 2.4GHz ?
or my Q about the distance you were wanting to try and use it over ?

if it really is 2.4GHz then just about everything so far spoken about it in this topic is pretty much irrelevent

cheers
Dave

 

[kneegrow]

it aint gonna work.... inside the PC case its going to be shielded by the case and be even worse than the existing PCB antenna. winding onto a ferrite core is just going to produce a basic RF choke and thats going to defeat the purpose as well.

you didnt answer my Q as to why you think its 27MHz where did you get that info from
when I posted info from the logitech site that pretty much said its 2.4GHz ?
or my Q about the distance you were wanting to try and use it over ?

if it really is 2.4GHz then just about everything so far spoken about it in this topic is pretty much irrelevent

cheers
Dave

I found a couple sites stating 2.4 Ghz, but not on logitechs site or the user guide. Also the guide says to place the receiver within 8" of the keyboard/mouse (see image), and the antenna's in the keyboard & mouse are a 7" and 6" loop respectively. seems way too large for a 2.4 Ghz antenna. but the large antenna's and extreme close placement of the receivers screams LOW frequency UNDERSIZED antenna to me. the logitech site just states "RF wireless" and not "Bluetooth" or "2.4" like they do for their higher end models. it won't even work reliably at 14" although the specs say 6'... The reason I went wireless was to keep an uncluttered workspace. this blows...