How to strengthen signal with the R170 Antenna - Page 5

Ikarus · 12-10-2007

Quote:

Originally Posted by Zeiser50

This is a resonance phenoma : each time the total lenght of the antenna is good, the number is low -> I select 37 cms for the next test

I find this result a bit suprising. Is what you're saying that with a wire of length lambda/8 (37.5cm), one is getting better results than with one of length lambda/4 (75cm)?

**etyu** · 12-10-2007

Quote:

Originally Posted by Zeiser50

Ok ....
Now, the conclusion :
- wire can be any gauge
- only one wire, soldered on the metal part, just below the transparent cable
- lenght of 37cm....

This might explain why the initial mod by DSB had good results at 15 in/37cm albeit on the R170 antenna.

**etyu** · 12-10-2007

Quote:

Originally Posted by mtiede

Great scientific testing. Nice to have the equipment

One thing that you apparently didn't test was whether that second wire some have used makes any actual difference. I think the second wire was to ground, but who knows whether there could be some sort of interaction in the coils of wire.

My experience initially with the R170 antenna was with just one wire and thought a second wire on the ground might make a difference but it didn't. I may have to go back and diassemble the R170 antenna and just try with one wire at 37 cm/14.5 in.

R230 antenna is on order (since I broke the one I already have).

Ikarus · 12-10-2007

Quote:

Originally Posted by etyu

This might explain why the initial mod by DSB had good results at 15 in/37cm albeit on the R170 antenna.

I'm not saying that 37cm would not work, so it might be worth trying as a compromise, but according to antenna theory, a dipole with a total length of lambda/2 (i.e. ~2 x 75cm) should still work best.

Sid · 12-10-2007

Quote:

Originally Posted by etyu

My experience initially with the R170 antenna was with just one wire and thought a second wire on the ground might make a difference but it didn't. I may have to go back and diassemble the R170 antenna and just try with one wire at 37 cm/14.5 in.

R230 antenna is on order (since I broke the one I already have).

Etyu, how much does that cost? Do you think they come in Diamond Silver?

**etyu** · 12-10-2007

Quote:

Originally Posted by Sid

Etyu, how much does that cost? Do you think they come in Diamond Silver?

SL antenna is a bit more expensive, list is around $80 and MB MSRP is $125 ! You may call to see what they have (MB dealers usually stock the black and iridium silver, but the warehouse may have the color that matches your car, give them the color code and they can check).

**dsb** · 12-10-2007

You lost me here:

Quote:

Originally Posted by Zeiser50

The equipment have used is a radio bench.

Seriously, thanks for all the work. Quite informative!

**-1-** · 12-10-2007

Zeiser50, I agree with others. Thanks for the scientific testing. Very interesting. I like the look of the SL antenna, but I can't beat the performance of the modified R170 antenna. Thanks everyone for their input on this thread.

zxxn · 12-10-2007

Quote:

Originally Posted by etyu

My experience initially with the R170 antenna was with just one wire and thought a second wire on the ground might make a difference but it didn't. I may have to go back and diassemble the R170 antenna and just try with one wire at 37 cm/14.5 in.

R230 antenna is on order (since I broke the one I already have).

It looks like everyone believe A is ground in R170 antenna. I tested and found A and B are connected. There is no ground in antenna.

Take a look at my second photo. Metal thread inside bottom of antenna is connected to nothing. It is just for mounting. So connecting one wire to A and connecting wire to B as ground(this is not true) is eventually connecting two separated wires to antenna.

I connected 75cm 24guage wire to A. I didn't get any gain on remote.

I think 75cm is good for FM frequency but not for remote frequency.
What is the frequency used by remote? I want to optimize antenna length for remote frequency.

**etyu** · 12-11-2007

I was going to ask the same question - what is the RF frequency used by smartKey?

**etyu** · 12-11-2007

Quote:

Originally Posted by zxxn

I connected 75cm 24guage wire to A. I didn't get any gain on remote.

I think 75cm is good for FM frequency but not for remote frequency.
What is the frequency used by remote? I want to optimize antenna length for remote frequency.

I observed a gain in the range of the SmartKey if you attach it to point B.

**Zeiser50** · 12-11-2007

Quote:

Is that an SL antenna or the R170?

This analysis has been done on SL antenna.

Quote:

I find this result a bit suprising. Is what you're saying that with a wire of length lambda/8 (37.5cm), one is getting better results than with one of length lambda/4 (75cm)?

Do not forget that the antenna lenght is the total lenght (including the PCB), as there is adaptation (capacitor+resistor+ PCB patch). 75cms is not the antenna lenght, it is the lenght of additional cable.

Quote:

I'm not saying that 37cm would not work, so it might be worth trying as a compromise, but according to antenna theory, a dipole with a total length of lambda/2 (i.e. ~2 x 75cm) should still work best

Correct. but antenna theory (dipole) is based on simple antenna (no adaptation). Also, a single dipole (75cm) is ok with a gnd plane (car configuration).

Quote:

One thing that you apparently didn't test was whether that second wire some have used makes any actual difference. I think the second wire was to ground, but who knows whether there could be some sort of interaction in the coils of wire.

Right : Usually, the antenna lenght is measured between ground plane, and the highest point (in a single dipole configuration). Using a second wire as ground, which can generate a global coil becomes ...... what i call "plumbing" . Only a very specialist is able to answer. However, 2 wires inside an SL antenna is a lot (space wise) ...

Quote:

I connected 75cm 24guage wire to A. I didn't get any gain on remote.

I think 75cm is good for FM frequency but not for remote frequency.
What is the frequency used by remote? I want to optimize antenna length for remote frequency.

Not tested for remote control. It should be interesting to check it (but the frequency may depend of country regulations).

Quote:

I observed a gain in the range of the SmartKey if you attach it to point B.

Even if electrically the point A and B are identical, antenna point of view, a wire on point A extends the antenna lenght, and on point B create a new "dipole". In this configuration, plumbing ...... Also, as the frequency may be high (for the remote control, 833Mhz ?), the impact of any small wire may be increased.

Quote:

It looks like everyone believe A is ground in R170 antenna. I tested and found A and B are connected. There is no ground in antenna.

Right : A and B are connected (SL or R170). But there is a ground : the thread of the antenna is the antenna ground (car ground) (antenna thread and center pin should not be short circuited.

Quote:

Why not solder 35 cm (accounting for length of wire in the transparent part) at the tip of the transparent part and then wind the wire around the transparent part? This way, one doesn't have to pick apart the coloured molded plastic.

Below the result : if you solder the wire at the top of transparent cable, a lenght of 37 or 35cm has similar result (you can solder it also on the metal base of the transparent cable).
If this wire is wound around the transparent cable or around the plastic base does not globally modify the antenna behaviour (for purist, the noise floor is better around plastic base, but sensitivity is less).
The figure below is the result.

**-1-** · 12-11-2007

Quote:

Originally Posted by etyu

I observed a gain in the range of the SmartKey if you attach it to point B.

Using the original "non specific" separate wiring lengths attached to "A" & "B", I have increased radio and remote reception. I've checked the remote range twice, and I'm getting close to 200 feet. I'm using a recently purchased new MB key fob. For those with older key fobs with original battery, a new battery might be a small investment for additional range. Here's a recent link on replacing the key fob battery. http://www.slkworld.com/slk-r171-gen...tery-died.html

zxxn · 12-11-2007

I just checked this morning and found FM reception is very good!

But, no improvement on remote.

Quote:

Originally Posted by -1-

I just checked the range (car in the garage) and I'm getting over 200 feet. Might even be better than the factory antenna. I checked from the rear, and then the opposite side (away from antenna) and still getting 200 feet plus, even in the woods. Both AM-FM reception are excellent with the car in the garage.

I really like to know -1-'s magic length.

**etyu** · 12-11-2007

Quote:

Originally Posted by Zeiser50

... if you solder the wire at the top of transparent cable, a lenght of 37 or 35cm has similar result (you can solder it also on the metal base of the transparent cable).

Thank you very much for this Michel

SLKjay · 12-11-2007

WOW!! Zeiser50 again I'm just blown away and I think your work is awesome.

12-10-2007	#88 (permalink)
-1- Don Join Date: Jun 2006 Location: Virginia USA Vehicle: SLK 55 ///AMG The MON55TER on the block Posts: 2,224 Country: Thanks: 54 Thanked 57 Times in 41 Posts	Zeiser50, I agree with others. Thanks for the scientific testing. Very interesting. I like the look of the SL antenna, but I can't beat the performance of the modified R170 antenna. Thanks everyone for their input on this thread. __________________ To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. *----------------1-----------------* --------SLK 55 ///AMG--------- THE MON55TER ON THE BLOCK

12-11-2007	#90 (permalink)
etyu Founding Member #2 / Ambassador Of Good Will Join Date: Jun 2006 Location: Orange County, CA Vehicle: 2008 SLK 55 Posts: 5,279 Country: Thanks: 376 Thanked 277 Times in 168 Posts	I was going to ask the same question - what is the RF frequency used by smartKey? __________________ *Eddy* To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Pewter/Beige, PIII package, Airscarf, Hands-Free Communication System, Lighting package Designo Black Leather Cover on e-brake handle, ( To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Bill T), SmartTop v1.0, Kleyman 3BFM (NoRegret Custom), Green Air Filters, *Mod. R170 ant.*, EuroClear sidemarkers w/PIAA PlasmaIon lamps, chromed front & rear turn indicator lamps, PIAA SuperPlasmaGTX front parking lamps, bilateral rear fog lamps enabled.

12-11-2007	#96 (permalink)
SLKjay SLK World Member Join Date: Nov 2007 Location: Phillips Ranch, CA Vehicle: '98 SLK230 Other Toys: '96 328IS Posts: 58 Country: Thanks: 0 Thanked 0 Times in 0 Posts	WOW!! Zeiser50 again I'm just blown away and I think your work is awesome.