How to strengthen signal with the R170 Antenna - Page 11

**Zeiser50** · 01-24-2008

The theory :
AM frequency (150 / 280Khz) is lower than FM (90 / 110 Mhz)
-> FM wave lenght (roughly 3 meters) is shorter than AM wavelenght (200/300 meters !)
-> The rule for the 37 cms of the FM (1/8 wavelenght) will not give a realistic AM cable lenght (31 meters) !!
For weather band (162.500Mhz), the theoretical cable lenght should be 1.77 meters. if we apply the same 1/8 rule, cable lenght should be 22 cms

Practically :
FM : 37 cms / Weather :22 cms / AM : the longer the best

you can try from 37cms and remove cm per cm up to 30cms. If you perform the test, in order to have a good comparison, you have to stay at the same place (the body may interfere with the radio reception). Based on my knwoledge, something around 33 cms should be interesting.

If needed, i can give a try on the test equipment in order to have a more precise value.

**-1-** · 01-24-2008

Whoa, I'm getting a headache here. I was lucky when I did mine. I followed DSBs directions and had it done in less than 30 minutes. Exceptional range and AM-FM reception. I had to order another R170 antenna for my wife's SLK. Tried several variations trying to replicate the success I had on mine. I soldered and re soldered several times. Got to the point where SmartTop reception was terrible. Due to excessive heat, the clear plastic with antenna lead loosened. One I realized it, I gently squeezed the shiney metal base with pliers and reception improved equal to mine. Not sure if anyone encountered the same problem. I'd be surprised if both antennas have the same length wiring. I think if it's close, it will work. Both cars are exceeding 250ft range. I don't intend to diminish the hard work and scientific testing that many have accomplished. I've enjoyed this thread.

**dsb** · 01-24-2008

Who would'a thunk a cheapo mod would get so many hits?!

noregret4life · 01-25-2008

If anyone is going to try the cut away method, perhaps this may be a good way to go about it:

Measure out 37cm.
Measure out 1cm intervals and mark them with a marker till which ever length you want to test to.
Then coil the wire.
Standing in the same spot outside(radio turned up to whichever AM station you want to get, or going in and out of the car) simply start to cut away on the intervals from the Top down.

This way you save yourself all the screwing around, and can finish the test fairly quickly.

Good luck...

And yes. this is a great thread... thanks to all who made it happen!

editor58 · 01-25-2008

Quote:

Originally Posted by noregret4life

If anyone is going to try the cut away method, perhaps this may be a good way to go about it:

Measure out 37cm.
Measure out 1cm intervals and mark them with a marker till which ever length you want to test to.
Then coil the wire.
Standing in the same spot outside(radio turned up to whichever AM station you want to get, or going in and out of the car) simply start to cut away on the intervals from the Top down.

This way you save yourself all the screwing around, and can finish the test fairly quickly.

Good luck...

And yes. this is a great thread... thanks to all who made it happen!

I was thinking about doing that very thing!! It's Friday TG... maybe this weekend!
I can't resist a good experiment. I'll fit it in between my helicopter repairs... Gravity is such a Bitch!

-editor

PsychoAzn · 01-25-2008

i don't get it...

how come most people think R171 looks better with r170 short antenna...

no offense.... just curious...

editor58 · 01-25-2008

Quote:

Originally Posted by PsychoAzn

i don't get it...

how come most people think R171 looks better with r170 short antenna...

no offense.... just curious...

Most of use here believe MB destroyed the lines of the SLK with a big black whip antenna. I also catch it sometimes as I walk through the garage.

It's a poor design execution of what should have been an elegant design solution. The SL Antenna is a short stubby.... It's like the engineers said, let's put a big long black rod sticking out of the fender... "Yea, Fritz... das is perfect" This was done while the designers were drunk at Oktoberfest

. IT'S UGLY!!! IMHO

-editor

**nevets** · 01-25-2008

Quote:

Originally Posted by PsychoAzn

i don't get it...

how come most people think R171 looks better with r170 short antenna...

no offense.... just curious...

Sometimes "Less is More"....IMO it looks like an afterthought... no offense.

noregret4life · 01-25-2008

Ok, so i may have made mine a little longer then i thought.

I purchased my wire from home depot. I think it was called "security wire" . The spool stated that it was 20g 2 contact (2 wires)

I had them cut it at around 3ft. (the guy gave me a little extra)
I cut off the outer plastic casing to end up with 2x 20g wires of the same length.
From one of them i cut away, what i thought i measured to be exactly 37cm, However now that i go back to remeasure it, i actually cut away exactly 15.5" or 39.37cm. < no idea what i was thinking, but fact is fact.

Besides the extra 2.37cm length, the other thing that perhaps could change the results is the actual thickness of the plastic casing surrounding the 20g Solid copper wire. This could change the results for both FOB and Radio.
Also, this would change the amount of wire that can be coiled and insterted into the R170 plastic cover.

In my case, the plastic surrounding the wire is rather thin, and i feel i can fit at least another 3-5cm+ on top of my 39.37cm.

I don't have a radio background and have no idea what any of this means for FM - AM - FOB, but perhaps this update changes a few things... or perhaps i should cut away the extra 2.37cm

... ??? Maybe someone can exmplain my results.

**-1-** · 01-25-2008

Quote:

Originally Posted by editor58

It's a poor design execution of what should have been an elegant design solution. The SL Antenna is a short stubby.... It's like the engineers said, let's put a big long black rod sticking out of the fender... "Yea, Fritz... das is perfect" This was done while the designers were drunk at Oktoberfest

. IT'S UGLY!!! IMHO

-editor

Now I understand how we got the BUF (big ugly f****r) style antenna. Das is perfect.....
Brillant Editor!

**Zeiser50** · 01-27-2008

Noregret,
here is some explanation (more clear i hope):
The difference between FM /AM / FOB is the frequency used for the transmission.
Any antenna shall be adapted to the frequency that it is designed for. This adaptation can be done with a special antenna shape, or/and lenght.

In our case (simple antenna), the adaptation is the lenght of the antenna : the lenght is defined depending of the frequency you would like to receive : there is ideal lenght (defined by the theory), and the reality (it may be impossible to apply the theory). As an example, the theory for ideal FM antenna lenght is 3 meter, which is quite impossible on a car. As substitution, the antenna lenght may be 1/2, 1/4, 1/8, .... of the original lenght. This is the reason why CB antenna lenght is more important than FM antenna (the theory for ideal CB antenna is roughly 12 meters).
-> 3 meter divided by 8 = 37cms. Here is the origin of the 37 cms (if we divide 3 meter by 4, the result will be better, but the wire lenght will be too long to be installed into the antenna housing.)

If you have a look on #81 on this thread, you will have a curve which gives you the antenna performance vs lenght : a low value means a good result : you will oberve that it is cyclic : 57 / 43 / 37 cms has the same performance.
In your case, 39 is between 43 / 37 . As consequence, it works, but maybe not as good as a 37cms lenght.

All these explanation can be applied on AM and FOB also. However, as the frequency are not the same, the lenght result is different.

To summarize : either the lenght is adapated to one of these radio range (FM, AM or FOB), and the two others will be not so good, or a kind of consensus is done to select a lenght which is quite good for every radio range. In this case, only experimentation can be done, as the car body, wire, coil diameter, antenna amplifier, .... may interfere.

I would recommend to remove 2 cms in your case : it should enhance FM reception. For the AM and FOB, Eddy and other guy has made some interesting test which may be reused.

HwoALanG · 02-05-2008

Quote:

Originally Posted by etyu

Yup.

Word of caution: Do not touch the central silver hollow attachment point in the SL antenna when disassembling. I must have misaligned that piece when I was testing and broke it when I reattached the SL antenna

this after all the testing. Now I have to call MB parts department on Monday. I hope they have a dented one that they want to throw away as I only want the inner/central piece.

any luck on getting inter piece?? cause someone who was sholdering broke my pin... stupidity...tsk tsk

anyway~ there are still imporvment on radio reception... little suprised but ~ i'm happy

**etyu** · 02-10-2008

Quote:

Originally Posted by HwoALanG

any luck on getting inter piece?? cause someone who was sholdering broke my pin... stupidity...tsk tsk

anyway~ there are still imporvment on radio reception... little suprised but ~ i'm happy

Sorry for the late reply, HwoAlanG, I didn't see this post (plus beeing moderately busy at work and at home).

Soldering doesn't work.

I had to purchase another SL antenna. The parts people tried to look for an SL ant that may have been partially/cosmetically damaged and may be lying around in the shop, so I could just get the inner central part but no such luck.

While the SL antenna looks very nice, the R170 ant is not that bad looking. With the more-than-enough range for the SmartKey and good FM reception after the mod, I now use the mod R170 antenna. The SL ant is kept in reserve.

muimui · 02-18-2008

guys just saw this antenna on ebay
http://cgi.ebay.com/ebaymotors/High-...em200199324922

and it claims to have "high performance guarantee exact sending and reception ability", is that for real?

**-1-** · 02-18-2008

I doubt it, and not without modifications. Stay with the modded R170. It's a proven winner, cosmetically superior, with equal or greater performance than the factory antenna.

muimui · 02-18-2008

thanks -1- i'll order the r170 tomorrow and try the mod as soon as i get it! =)

**dsb** · 02-18-2008

Quote:

Originally Posted by muimui

guys just saw this antenna on ebay
http://cgi.ebay.com/ebaymotors/High-...em200199324922

and it claims to have "high performance guarantee exact sending and reception ability", is that for real?

I recall people buying that antenna a couple years ago. I can't remember one good review. Like Don suggested, stick with the modded R170 antenna. Proven results.

01-24-2008	#201 (permalink)
Zeiser50 Elite SLK World Member Join Date: Mar 2007 Location: Paris Vehicle: SLK 55 AMG Other Toys: Bike : '84 Z1300-6 Posts: 506 Country: Thanks: 6 Thanked 18 Times in 14 Posts	The theory : AM frequency (150 / 280Khz) is lower than FM (90 / 110 Mhz) -> FM wave lenght (roughly 3 meters) is shorter than AM wavelenght (200/300 meters !) -> The rule for the 37 cms of the FM (1/8 wavelenght) will not give a realistic AM cable lenght (31 meters) !! For weather band (162.500Mhz), the theoretical cable lenght should be 1.77 meters. if we apply the same 1/8 rule, cable lenght should be 22 cms Practically : FM : 37 cms / Weather :22 cms / AM : the longer the best you can try from 37cms and remove cm per cm up to 30cms. If you perform the test, in order to have a good comparison, you have to stay at the same place (the body may interfere with the radio reception). Based on my knwoledge, something around 33 cms should be interesting. If needed, i can give a try on the test equipment in order to have a more precise value. __________________ To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. ------Michel------ -SLK 55 AMG 2005- Last edited by Zeiser50; 01-24-2008 at 03:46 PM. Reason: calculation mistake

01-24-2008	#202 (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	Whoa, I'm getting a headache here. I was lucky when I did mine. I followed DSBs directions and had it done in less than 30 minutes. Exceptional range and AM-FM reception. I had to order another R170 antenna for my wife's SLK. Tried several variations trying to replicate the success I had on mine. I soldered and re soldered several times. Got to the point where SmartTop reception was terrible. Due to excessive heat, the clear plastic with antenna lead loosened. One I realized it, I gently squeezed the shiney metal base with pliers and reception improved equal to mine. Not sure if anyone encountered the same problem. I'd be surprised if both antennas have the same length wiring. I think if it's close, it will work. Both cars are exceeding 250ft range. I don't intend to diminish the hard work and scientific testing that many have accomplished. I've enjoyed 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

01-24-2008	#203 (permalink)
dsb Elite SLK World Member Join Date: Jul 2006 Location: NorCal Vehicle: '06 slk55 Posts: 1,176 Country: Thanks: 67 Thanked 120 Times in 42 Posts	Who would'a thunk a cheapo mod would get so many hits?! __________________ SOLD! 06 Mercedes Benz SLK55 Caspian Blue / Black & Ash *To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.*

01-27-2008	#211 (permalink)
Zeiser50 Elite SLK World Member Join Date: Mar 2007 Location: Paris Vehicle: SLK 55 AMG Other Toys: Bike : '84 Z1300-6 Posts: 506 Country: Thanks: 6 Thanked 18 Times in 14 Posts	Noregret, here is some explanation (more clear i hope): The difference between FM /AM / FOB is the frequency used for the transmission. Any antenna shall be adapted to the frequency that it is designed for. This adaptation can be done with a special antenna shape, or/and lenght. In our case (simple antenna), the adaptation is the lenght of the antenna : the lenght is defined depending of the frequency you would like to receive : there is ideal lenght (defined by the theory), and the reality (it may be impossible to apply the theory). As an example, the theory for ideal FM antenna lenght is 3 meter, which is quite impossible on a car. As substitution, the antenna lenght may be 1/2, 1/4, 1/8, .... of the original lenght. This is the reason why CB antenna lenght is more important than FM antenna (the theory for ideal CB antenna is roughly 12 meters). -> 3 meter divided by 8 = 37cms. Here is the origin of the 37 cms (if we divide 3 meter by 4, the result will be better, but the wire lenght will be too long to be installed into the antenna housing.) If you have a look on #81 on this thread, you will have a curve which gives you the antenna performance vs lenght : a low value means a good result : you will oberve that it is cyclic : 57 / 43 / 37 cms has the same performance. In your case, 39 is between 43 / 37 . As consequence, it works, but maybe not as good as a 37cms lenght. All these explanation can be applied on AM and FOB also. However, as the frequency are not the same, the lenght result is different. To summarize : either the lenght is adapated to one of these radio range (FM, AM or FOB), and the two others will be not so good, or a kind of consensus is done to select a lenght which is quite good for every radio range. In this case, only experimentation can be done, as the car body, wire, coil diameter, antenna amplifier, .... may interfere. I would recommend to remove 2 cms in your case : it should enhance FM reception. For the AM and FOB, Eddy and other guy has made some interesting test which may be reused. __________________ To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. ------Michel------ -SLK 55 AMG 2005-

02-18-2008	#215 (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	I doubt it, and not without modifications. Stay with the modded R170. It's a proven winner, cosmetically superior, with equal or greater performance than the factory antenna. __________________ 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

01-25-2008	#204 (permalink)
noregret4life Elite SLK World Member Join Date: Jun 2006 Location: NJ Vehicle: '05 SLK350 Posts: 1,092 Country: Thanks: 1 Thanked 17 Times in 11 Posts	If anyone is going to try the cut away method, perhaps this may be a good way to go about it: Measure out 37cm. Measure out 1cm intervals and mark them with a marker till which ever length you want to test to. Then coil the wire. Standing in the same spot outside(radio turned up to whichever AM station you want to get, or going in and out of the car) simply start to cut away on the intervals from the Top down. This way you save yourself all the screwing around, and can finish the test fairly quickly. Good luck... And yes. this is a great thread... thanks to all who made it happen!

01-25-2008	#206 (permalink)
PsychoAzn Senior SLK World Member Join Date: Jun 2007 Location: Brisbane, Australia Vehicle: 2006 SLK350 Other Toys: 2005 ML350, 2007 C200 Posts: 105 Country: Thanks: 6 Thanked 1 Time in 1 Post	i don't get it... how come most people think R171 looks better with r170 short antenna... no offense.... just curious...

01-25-2008	#209 (permalink)
noregret4life Elite SLK World Member Join Date: Jun 2006 Location: NJ Vehicle: '05 SLK350 Posts: 1,092 Country: Thanks: 1 Thanked 17 Times in 11 Posts	Ok, so i may have made mine a little longer then i thought. I purchased my wire from home depot. I think it was called "security wire" . The spool stated that it was 20g 2 contact (2 wires) I had them cut it at around 3ft. (the guy gave me a little extra) I cut off the outer plastic casing to end up with 2x 20g wires of the same length. From one of them i cut away, what i thought i measured to be exactly 37cm, However now that i go back to remeasure it, i actually cut away exactly 15.5" or 39.37cm. < no idea what i was thinking, but fact is fact. Besides the extra 2.37cm length, the other thing that perhaps could change the results is the actual thickness of the plastic casing surrounding the 20g Solid copper wire. This could change the results for both FOB and Radio. Also, this would change the amount of wire that can be coiled and insterted into the R170 plastic cover. In my case, the plastic surrounding the wire is rather thin, and i feel i can fit at least another 3-5cm+ on top of my 39.37cm. I don't have a radio background and have no idea what any of this means for FM - AM - FOB, but perhaps this update changes a few things... or perhaps i should cut away the extra 2.37cm ... ??? Maybe someone can exmplain my results.

02-18-2008	#214 (permalink)
muimui SLK World Member Join Date: Feb 2008 Location: Canberra Vehicle: r171 SLK 350 Posts: 16 Country: Thanks: 0 Thanked 0 Times in 0 Posts	guys just saw this antenna on ebay http://cgi.ebay.com/ebaymotors/High-...em200199324922 and it claims to have "high performance guarantee exact sending and reception ability", is that for real?

02-18-2008	#216 (permalink)
muimui SLK World Member Join Date: Feb 2008 Location: Canberra Vehicle: r171 SLK 350 Posts: 16 Country: Thanks: 0 Thanked 0 Times in 0 Posts	thanks -1- i'll order the r170 tomorrow and try the mod as soon as i get it! =)

02-19-2008	#218 (permalink)
ghostdunks