Treo Antenna Hack

I am in the process of making a clip on mount and an antenna that will hopefully improve reception and signal strenth over the stock antenna. This modification will work on 600's and 650's, both CDMA and GSM.

The stock antenna is appropriately mounted in the antenna nub inside the treo. It is this curly wire coiled up and shoved into that confined space. the thought is a long straight antenna will have more influence on the EM field over a coiled crammed up wire, and therefore more efficently transmit and recieve electromagnetic energy.

When I was a kid I was able to improve signal strenth on my TV by wrapping the antenna with aluminum foil. I suppose thats one way to go about this... I could try to wrap my treo in aluminum foil, but it may short out the aluminum foil hat I wear to keep the folks at PalmOne from monitoring my thoughts, and that would be bad. So I think im gonna go about this a different way.

Instead Im going to contsruct a antenna that will be exactly the right lenth for the CDMA and GSM bands. Center freq for those is 900MHz and 1800mhz making the same lenth antenna work for both frequencies. A full wavelenth for 1800MHz would be exactly 6.24 inches, and 6.24 inches is exactly 1/2 wavelenth for the 900MHz band, which is just fine. Recent polls on the shadowchat show that most verizon treo owners dont want to carry a 12.48 inch fullwave antenna, so the 1/2 wave antenna should work just fine.

I have ordered a cable, and Im going to make a mount out of an old aluminum treo case. The antenna itself I think im going to make out of a coat hanger (thanks cactus!) and it should be a pretty slick unit. I will post pics as soon as I have it together.

I made more progress with the antenna. I decided on a way to mount the antenna, as well as a way to make it safe to put in a pocket. All this with no additional cost to the project. In fact most of the antenna would have been built today if I could have found my supply of dremel cutt off wheels. I cant seem to find them, and I might have to go buy some more... untill then I dont want to cut anything metal because I want this to look descent.

A moment of silence please, 2 ballpoint pens gave thier lives for this project. I am going to use cheap ballpoint pen casings to reinforce the antenna. I "borrowed" the pens from my employer.. so im not going to add them to the cost of this project. The pen casings will keep the antenna from being bent and also to keep the antenna form sticking me when its in my pocket. Incidently I also borrowed a wire coat hanger from another anonymous source, but im only gonna cut 6.24 inches out of it and then I fully intend to return the coat hanger. This I also dont add into the total cost of the total project.

I built it! I have the mount and the antenna itself built, an im only waiting on the cable to arrive. Im gonna carry it around anyway to make sure that the mount is sturdy enough. Im not terribly happy with the feel of the antenna and may have future versions mounted differently.

wow, I'm stoked!

My esteemed associte Ant from the shadowmite chat has brought to my attention a slight error in my math. It turns out my inital research came up with 900 mhz and 1800 mhz for cdma. While those are close to center freq for GSM phones, CDMA phones really run on 800 mhz and 1900 mhz. I seemed to have transposed the numbers.

This does not pose a big problem to the project. The stage im at now allows me to easilly change the antenna lenth fot the correct freqs. This means I need to make a special antenna for sprint, verizon, and GSM model phones. I am in the unique position to test a few of these models personally. I have a verizon phone now, but my contract will be up soon at whitch time I will switch to sprint. So the prototype verizon antenna will be 7.02" long for 1/2 wavelenth, and when I switch over to sprint I will trim the antenna down to 5.9".

Additionally, I called in a personal favor with shadowmite himself to program me a simple app that will display the RSSI and any other useful antenna variables on the screen. This will give me numbers to measure actual gains in performance.

The antenna mount I made also did not survive the brutal torture testing. I did see what did work and what didnt, and Im confident that I can build one that will be significantly sronger. I hope to work on it a bit tommorow, as it is getting late here. I'm going to move the antenna from the back to the left hand side (next to the antenna) as suggested by johnski and drgf from the chat because I think it will both give it a better feel and the body of the treo will help reinforce the antenna.

This discrepency in antenna lenths makes me worry about the stock antenna. In order to have an antenna that will respond equally with 800 hmz and 1900 mhz you would have to find a common multiple. I was thinking that with the 900 and 1800 as the freq bands, you would have an easy common multiple. But with the 800 and 1900 freqs, you have to go a bit further down to find a common muliple. In short, you end up with a short antenna that suprises me would work at all. This line of thinking favors the 800 mhz (verizon) band, as the multiple would favor that band better as well as the lower freq having more penetration through solid object and ground following proberties over the higher freq band. Possibly this is why verizon advertises as having a better network? This antenna should blow away any discrepencies with the service providers. I'm actually gaining confidence in the project. I approached this with the thought that I could make an antenna that would be possibly better than stock. If my new line of thinking is correct, this should be so unbelieveably better than stock that I could possibly market this...

GO SPY GO!

I have the program Shadowmite made for me, you guys can download it at: http://discussion.treocentral.com/attac ... entid=9162
It works great. Just ignore the little error message...

A word about rssi... It is recieve signal strenth indication, measured in -dbm. It is part of how CDMA phones measure thier signal. The strenth of the outgoing signal strenth is measured against the signal recieved from the tower, giving you an indication of the service signal strenth. Cell phones can boost power to reach the cell towers if necessary (and can reduce transmit power if necessary), so both signals alter the rsn (relative signal to noise ratio). As a benchmark I have taken my phone around with me and watched the numbers. At home where I get 4 bars I have seen numbers as low as 56 but normally in the high 60's, and at work where I am constantly dropping calls im in the 95-115 range.

I have seen some weird varibles come into play while monitoring the rssi. I gain nearly 10 points on the rssi when i hold the phone above the plane of the car windows as opposed to lower (in a cup holder). This usually isnt enough to gain or lose a "bar" but is a measureable difference with this program.

Again I aint got no love for the GSM guys, however Shadowmite included you guys in his program... just ask him how the program measures the GSM signal as it is more complex than I am willing to go into right now. All I am currently working on is an antenna for a verizon and then a sprint phone, both CDMA, I wont go into how GSM works. Maybe later...

As for any updates on the antenna, I havent built the redesigned one yet. Seeing as how my work schedual sucks this week I may have to bring my dremel in to work with me tonight...

I got my antenna cable today, I got it today from http://stores.ebay.com/AWS-WIRELESS I found one of his that was pretty cheap, and the shipping and processing time wasnt so bad. If you find anything with a male FME connection cheaper, but it. I paid $4.00 and had a $3.75 shipping and handling fee.

As for the the cable itself, it does stick out of the back of the treo quite a bit, you guys who thought you'd get a pretty compact design with this mod will be sorely dissapointed. As my prototype is going to be somewhat bulky, Im gonna let this fly. A professional antenna mod, if one is ever concieved, will be a variarion on Shadowmites idea. His idea was to fabricate an antenna of some ideal lenth moulded in a custom peice, replacing the stock antenna nub. I would consider doing something similar, but running the antenna the lenth of the treo.

I performed a test, just to make sure that what we know about the treo is true. I plugged in the cable and instantly lost all signal. This is good. This means that plugging into the fme connection on the back does indeed isolate the stock antenna. As the cable is RF shielded, and there was no singal, means that the shielding works. This is important because the antenna lenth is highly crucial to making a better antenna, and we dont want RF leaking in or out.

I will try to get something together over the next few days.

Well its together and going through extensive testing. At first I was expecting the RSSI to jump on average, however I was sorely dissapointed. The RSSI actually got a tad worse, but after a bit averaged out the same as the stock antenna. This I took to mean that my treo wasnt recieving any better. I was wrong. I got to work, a place were my service drops off normally, and I found that I could make normal calls. My RSSI sucked, but i was able to make a call with an RSSI higher than 105. Normally a 105 RSSI gives me a "no service" indication, and I have seen an RSSI as high as 115 here at work.

So Im gonna call this a success, I am able to make normal calls under conditions were this was impossible. On top of all that the call quality (clarity) has gone up noticibly in conditions were it had suffered. Testing will continue, possibly with a different antenna configuration. This antenna uses no ground plane, a concept that I know of but usually take for granted. A dipole setup could be fabricated and would use the opposite pole as a ground plane, but for now im not too worried. Testing is ongoing at this time. I will try to get pics up before defcon, if not it will definitely be in the defcon pics.

Good work and I can't wait to see pics. Of note, I believe that ZLauncher already has a singal strength monitor installed. If you press on the signal strength indicator in ZLauncher, you'll get a pop-up showing the signal strength in dBs.

Thanks beepof death, thats good information, I didnt know that and it does infact coincide with the RSSI numbers from Shadowmite's program. I wonder (i doubt actually) if it gives relevant info for the gsm guys, as thier system is a bit different.

Well I broke the antenna today. The little wire soldered onto the end of my antenna broke while in my pocket. This is a good thing, actually, because i wanted to try one more antenna configureation. I wanted to try a dipole setup, so I changed the antenna to a dipole using the same materials. I use the same mount, but the wire enteres from the center making it much more protected.

Results: OMG this is the antenna configureation I will be reccomending to friend and foe alike. This is definiteally better. Just like the long antenna the RSSI didnt improve, but with the dipole a RSSI of 95 means 3 "bars" on the phone app. There is definitaly other variables that go into that measurement, so I will be using that as the meathod of comparing sinal quality. RSSI alone doesnt seem to work as I had hoped, I had wanted a more scientific way of measuring signal strenth. Zlauncher seems to not meausure anything other than rssi, because it has told me I had signal when I didnt have it, and with this antenna the opposite is true, with a 95 RSSI it says I have very little signal when in fact i have great signal. RSSI alone is only a good measurement when dealing with identical antennas. I need a better way to measure.

But its together, it works, and Im pimping it out for defcon. I have a graphic of Sehiroth from FFVII standing in the burning city of Nibelheim. On a completely separate tangent Final Fantasy VII : Advent Children is coming out this fall. Woo hoo this will be similar to the last Final Fantasy movie in that it will be hugely CG intensive, but this one will actually be a GOOD movie.

The prototype antenna got its last coat of clearcoat today, and is all ready for defcon. I got my backpack hacked and ready to go, its pretty sweet and perfect for defcon. I am gonna have a great time! Look for my antenna in the defcon pics we put up!

The treo antenna got mixed reviews at defcon, and it held up to the abuse of being jumbled around a lot of heavier bits of high tech wizardry. For the most part folks thought it was some kind of gadget or anything but an antenna, and was more suprised by the novelty of a PDA/phone hybrid. The treo savvy folks for the most part decided that it was too obnoxious and violated the compact and sleek design of the treo. Shadowmite is confident that some kind of hybrid antenna lenth can be found and has me busy researching other antenna products looking for the right lenth to accomidate both cdma freq bands.

Any pics??

The treo antenna got mixed reviews at defcon, and it held up to the abuse of being jumbled around a lot of heavier bits of high tech wizardry. For the most part folks thought it was some kind of gadget or anything but an antenna, and was more suprised by the novelty of a PDA/phone hybrid. The treo savvy folks for the most part decided that it was too obnoxious and violated the compact and sleek design of the treo. Shadowmite is confident that some kind of hybrid antenna lenth can be found and has me busy researching other antenna products looking for the right lenth to accomidate both cdma freq bands.

http://flickr.com/photos/treochat/29480910/

This is the MKII prototype as it appears today, this photo was taken at day 1 of DEFCON. This build has survived through some rough testing conditions. Notice the totally cool Final Fanasy VII graphic!!!!