track telemetry - data radio

Hardware inside and outside of the ECU
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

track telemetry - data radio

Post by AndreyB »

I am afraid of radio, my perception is that's dark voodoo magic and it simply would not work unless I have a Ms degree in physics.

I am sure that with enough $$$ some easy-to-use solutions are there, but I do not have $$$.

Are there any units which would allow remote telemetry on a track (so think relatively open space but with some elevation, car is always within a mile from paddock. On average we pit in a huge garage.

Here are some random used eBay options:

Maxon Midland SD-125E V2 5W VHF Data Radio Telemetry Module 148-174MHz

or

http://www.ebay.com/itm/Lot-of-5-Motorola-VRM-650-Data-Mobile-Radio-F3454A-VRM650-w-Brackets-/291442823960

Do these items have anything to do with what I am thinking about?
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
puff
contributor
contributor
Posts: 2961
Joined: Mon Nov 11, 2013 11:28 am
Location: Moskau

Re: track telemetry - data radio

Post by puff »

It depends upon how much data you want to send and how often you want to do so. You might want to look at RC flight equipment. E.g. they use 9ch RC system which basically sends these 9 bytes quite often.
There are some purpose-built telemetry system as well, but as far as I understand they don't send that much data. (they use such systems to transmit gps signal, some voltages, amperage, speed, altitude, RSSI and that's it)
Yet another option is getting a set of video transmitter and receiver, and an OSD chip on the transmitting part, so that you can overlay muliple values ontop the video. On the reveiving part you might need some decoding software.
The use of all this stuff might be restricted by the USA legislation (probably Jared knows the local requirements much better)
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Looks like these are not really suited for peer to peer, I would the central station also?

Some fun thread at https://forums.radioreference.com/motorola-forum/179932-motorola-vrm-650-a.html
Ok for those who stumble upon this page in the future, what you need is RIB box RLN4008 (40 bucks on ebay), an old laptop that has a floppy drive, a DOS 6.22 (Bootdisk.Com - Free Windows Bootdisks, Free DOS boot disk), and MCS2000 MCS RSS Ver R05.00.00 you can get as a torrent. I really hope Motorola goes bankrupt oneday as one of the most useless p.o.s companies out there.

1. Make bootdisk, boot under DOS 6.22
2. Copy the RSS to 2 floppies, disk 1 and disk 2.
3. Install the RSS
4. Connect DB9 male to DB25 female cable (Radioshack Cat. No. 26-287) to the RLN4008 RIB
5. Connect DB9 male to RIB and DB9 female to the serial port on your computer
6. Launch the RSS and program in the frequencies

That is how its done. Dont waste your time looking for WinRSS you wont find it, its probably going to cost you money. Dont try to program it directly without the RIB, it wont work. You need RIB to program in the frequencies but you dont need RIB to use it later.
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
puff
contributor
contributor
Posts: 2961
Joined: Mon Nov 11, 2013 11:28 am
Location: Moskau

Re: track telemetry - data radio

Post by puff »

I guess all these solutions are dirt cheap on ebay exactly because they are useless. What's the achievable data rate? I can't find specs. 4096 bps?
User avatar
mobyfab
Posts: 139
Joined: Tue Oct 29, 2013 10:09 am
Location: Versailles, France

Re: track telemetry - data radio

Post by mobyfab »

Have a look at this: http://openlrsng.org
There are a ton of videos about it as well.

Some people make it work to 100Km+ with the right antennas, so around a track it should work just fine if the base station is in the middle. ;)
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

38K actually!

But yep, pretty depressing very closed-source universe https://www.reddit.com/r/amateurradio/comments/18eswj/reverse_engineering_motorolas_rss_software/
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

mobyfab wrote:Have a look at this: http://openlrsng.org
There are a ton of videos about it as well.
Now I know how rusEfi looks for people who have not invested a bunch of time into understanding it :)

Too many new keywords :( Is there a 101 introduction or a complete list of all components needed to establish a serial communication channel for 1.5 miles / 2 km radius?
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
mobyfab
Posts: 139
Joined: Tue Oct 29, 2013 10:09 am
Location: Versailles, France

Re: track telemetry - data radio

Post by mobyfab »

https://www.rcgroups.com/forums/showthread.php?2037442-Ultimate-LRS-40-km-APM-Telemetry-RC-link-for-54-(using-2-OrangeRX-1W-TX)

Basically we could mod this to send any kind of serial data we want, over long distances, full duplex :)
If you want to use the transceivers directly: http://www.hoperf.com/upload/rf/RFM23BP.pdf
User avatar
kb1gtt
contributor
contributor
Posts: 3758
Joined: Tue Sep 10, 2013 1:42 am
Location: ME of USA

Re: track telemetry - data radio

Post by kb1gtt »

I understand these LORA modules are reasonably good for this kind of thing.

https://octopart.com/rf-lora-868-so-rf+solutions-66465173

http://www.newark.com/rf-solutions/gamma-868-so/lora-transceiver-868mhz-9-6kbps/dp/68Y7682?mckv=k4M2bM8I&gross_price=true&CATCI=pla-289295517529&CAAGID=20389674261&CMP=KNC-GUSA-GEN-SHOPPING-68Y7682&CAGPSPN=pla&gclid=CNHp8o-FvtMCFZmCswodfQwFYQ&DM_PersistentCookieCreated=true&CAWELAID=120185550002980121

A key problem is line of sight. You won't have line of sight and relying on reflections is not going to work well. Multi-path is also an issue.

You could always get your ham licence, then you can do Amature TeleVison (ATV).
Welcome to the friendlier side of internet crazy :)
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

I can live without ATV, all I want is 9.6Kb

Are there any 9.6+Kb options without line of sight and without a license?
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
stefanst
contributor
contributor
Posts: 703
Joined: Wed Feb 17, 2016 12:24 am
Location: USA 08530

Re: track telemetry - data radio

Post by stefanst »

Depending on antenna, I'd guess a pair of simple RF transceivers should do:
https://www.sparkfun.com/products/12770
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

stefanst wrote:Depending on antenna, I'd guess a pair of simple RF transceivers should do:
https://www.sparkfun.com/products/12770
I do not have SPI on my laptop (unless I do)

Any optioons for more $ but with a case and RS232?
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
Rhinoman
contributor
contributor
Posts: 256
Joined: Thu Sep 24, 2015 2:14 pm
Location: Wiltshire, UK

Re: track telemetry - data radio

Post by Rhinoman »

puff wrote:I guess all these solutions are dirt cheap on ebay exactly because they are useless.
It depends what you want to use them for, those 144-174MHz units could be ideal for me, I have been experimenting with AIS reception using a walkie-talkie module but it doesn't work very well, because I can't turn off the AGC its difficult to detect the start of a transmission. Its a shame about the postage costs to the UK.

Its difficult to get high rates of data transmission at relatively low frequencies because the bandwidth tends to be quite low, you have to take the edges off to reduce the 'higher frequency' content of the signal before transmission and then reshape the signal on reception. I would look at the 2.4GHz upwards units
Rhinoman
contributor
contributor
Posts: 256
Joined: Thu Sep 24, 2015 2:14 pm
Location: Wiltshire, UK

Re: track telemetry - data radio

Post by Rhinoman »

russian wrote:
stefanst wrote:Depending on antenna, I'd guess a pair of simple RF transceivers should do:
https://www.sparkfun.com/products/12770
I do not have SPI on my laptop (unless I do)

Any optioons for more $ but with a case and RS232?
FTDI make a USB - SPI converter cable.
User avatar
kb1gtt
contributor
contributor
Posts: 3758
Joined: Tue Sep 10, 2013 1:42 am
Location: ME of USA

Re: track telemetry - data radio

Post by kb1gtt »

The e-bay device might work. Keep in mind you'll still loose communications during line of sight, so you'll want to have local buffering and handshaking, such that you don't loose data. I also have not seen the range yet. I see the below support page notes a 10ft distance for the loopback test. Do you see something that indicates it will work for a 1/4 mile range?

https://laird-ews-support.desk.com/customer/portal/articles/1896526-faq-how-do-i-perform-a-loopback-test-using-the-config-utility-for-connexlink-rs-232-after-successfully-reading-the-radios-?b_id=1996

It is common that the licence free technologies, are similar to your wireless phone. Those are limited in range because they are limited in radiated power. This device might have similar limitations, so check to see what they claim for a distance. Also keep in mind that distance is in the desert with no obstacles. You will have reflections and earth issues which will probably force you to around 50% to 80% of what ever they claim for a distance. Also keep in mind that other devices like cordless phones are likely to use this RF space and may cause interference.

Also keep in mind that the RF end of these can easily get half damaged. Basically they easily get zapped which results in only half or less of the output power. You are likely to find that e-bay ones work at your desk, but do not work the distance. While a new one is much more likely to work the distance. For $100-ish in a difference in price, I would suggest spend the $ to make sure it works properly.
Welcome to the friendlier side of internet crazy :)
User avatar
mobyfab
Posts: 139
Joined: Tue Oct 29, 2013 10:09 am
Location: Versailles, France

Re: track telemetry - data radio

Post by mobyfab »

kb1gtt wrote:I understand these LORA modules are reasonably good for this kind of thing.

https://octopart.com/rf-lora-868-so-rf+solutions-66465173

http://www.newark.com/rf-solutions/gamma-868-so/lora-transceiver-868mhz-9-6kbps/dp/68Y7682?mckv=k4M2bM8I&gross_price=true&CATCI=pla-289295517529&CAAGID=20389674261&CMP=KNC-GUSA-GEN-SHOPPING-68Y7682&CAGPSPN=pla&gclid=CNHp8o-FvtMCFZmCswodfQwFYQ&DM_PersistentCookieCreated=true&CAWELAID=120185550002980121

A key problem is line of sight. You won't have line of sight and relying on reflections is not going to work well. Multi-path is also an issue.

You could always get your ham licence, then you can do Amature TeleVison (ATV).
Lora is a no go, subscription fees, very slow (~200 bps) and data is capped. You are limited to only a few messages per day.
russian wrote:I can live without ATV, all I want is 9.6Kb

Are there any 9.6+Kb options without line of sight and without a license?
OpenLRS again. No license means ISM bands.
Forget about 2.4Ghz, look for 433Mhz.

You can also directly use this kind of modules: http://www.hoperf.com/rf_transceiver/modules/RFM69HCW.html
OpenLRS uses this one: RFM23BP (you can find it on eBay for $8)
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

mobyfab wrote:You can also directly use this kind of modules: http://www.hoperf.com/rf_transceiver/modules/RFM69HCW.html
OpenLRS uses this one: RFM23BP (you can find it on eBay for $8)
I guess I should have describe my want better: at this point I'd rather have an external device so that I am not soldering antenna connectors or else. What do you think about the CL4790?
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
mobyfab
Posts: 139
Joined: Tue Oct 29, 2013 10:09 am
Location: Versailles, France

Re: track telemetry - data radio

Post by mobyfab »

That should work just fine, as long as you have the 1 Watt - 900 Mhz version.
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Just called https://laird-ews-support.desk.com/ - tech support has picked up the phone right away, nice!

"CL4790-1000" - 1000 stands for 1W (older -100 and -200 models would be 0.1W and 0.2W), "up to 20 miles line of sight"

Guy on the phone recommended CL4490 model which is while technically same power showed better results from his experience, but CL4490 is client-server so you need one unit saying "server" and one unit saying "client"
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Got an amazing CL4490-1000 deal on eBay

Wall power supply 8v, ground on the outside, power on the inside of the OD 5.5mm/ID 2.8mm Adaptaplug "O" from bancrupt RadioShack
Attachments
CL4490-1000.jpg
CL4490-1000.jpg (860.35 KiB) Viewed 17651 times
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Pages #8 and #9 of integration guide and software screenshot bother me a bit with DTR and RTS pins. Tried GND and +4v from USB but did not work.

Maybe will try negative from a battery pack tomorrow? Need more RS232 cables and devices to play with, some Amazon orders placed.

Code: Select all

black - 1 - DCD
brown - 2 - rx
red - 3 - tx
orange - 4 - DTR
yellow - 5 - GND

violer - 7 - CTS
blue - 8 - RTS
green - 9
Attachments
screenshot.png
screenshot.png (224.86 KiB) Viewed 17644 times
Hardware Integration Guide - CL4490.pdf
(896.71 KiB) Downloaded 247 times
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Well, got second USB<>RS232 but things do not look great :(

From inside the garage we only get about 400ft range - pretty much to each end of my street, but not if you turn around the corner. Looks like that's on max 1W power output mode.

Any chance a different antenna would change things dramatically?

PS: CL4490: Interface Buffer Size Input/Output: 256 bytes each only
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
kb1gtt
contributor
contributor
Posts: 3758
Joined: Tue Sep 10, 2013 1:42 am
Location: ME of USA

Re: track telemetry - data radio

Post by kb1gtt »

City is really bad for that tech, lots of multipath issues and conflicting noise sources. Keep in mind cell phones and home portable phones are going to interfere with that technology. Can you try something a bit more open? I would expect things will get better as you get into an area that is more like your track.

What kind of antenna does it have? Can you post a picture of the antenna?

Also beware of SWR issues, you can easily damage radio's if the antenna is wrong. This SWR meter might not work, but it comes with some BNC adapters, and it might work well enough to know if your antena has a problem.
http://www.ebay.com/itm/Vintage-Arista-SWR-DB-Meter-Model-CB-1100-CB-Radio-Estate-item-Selling-for-parts-/332186672856?hash=item4d57de5ed8:g:dCMAAOSwqM1Ym5vS
Welcome to the friendlier side of internet crazy :)
Abricos
contributor
contributor
Posts: 849
Joined: Mon Aug 18, 2014 12:32 am
Location: Carteret, NJ 07008

Re: track telemetry - data radio

Post by Abricos »

User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Picture and user guide. Screenshot from integration guide.
Attachments
screenshot.png
screenshot.png (85.24 KiB) Viewed 17616 times
Hardware Integration Guide - CL4490.pdf
(896.71 KiB) Downloaded 214 times
User Guide - AC4490.pdf
(1.69 MiB) Downloaded 280 times
stock_antenna.jpg
stock_antenna.jpg (485.4 KiB) Viewed 17617 times
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: track telemetry - data radio

Post by AndreyB »

Are we getting to AC4490 RF Diagnostic Suite?
Attachments
Diagnostics_Suite_AC4490.pdf
(316.57 KiB) Downloaded 233 times
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
User avatar
kb1gtt
contributor
contributor
Posts: 3758
Joined: Tue Sep 10, 2013 1:42 am
Location: ME of USA

Re: track telemetry - data radio

Post by kb1gtt »

-100dbm is reasonably good sensitivity. Also the generic whip antenna tells me it should be reasonably good about SWR issues. SWR issues will still cause poor performance, but should not destroy the transmitter. This is good because it raises confidence that mag mounted antennas will probably be helpful.

http://www.ebay.com/itm/Alfa-ARS-AS01-Magnet-BASE-mount-dock-for-RP-SMA-antenna-fits-AWUS036H-AWUS036NH-/130717957240?hash=item1e6f65bc78:g:ouQAAMXQhpdR0KiL

Permanent installed in a metal plate is better performance.

http://www.ebay.com/itm/850-900-1800-1900-2170mhz-5dbi-3G-UMTS-GPRS-antenna-RP-SMA-male-wall-mount-RG174-/251754835765?hash=item3a9dc1ef35:g:JoIAAOxy0NtTECDm

Generally you need 6dbm to grab the radio's attention. A key problem you have in the city is all the reflections. If you have say line of sight, and it's at say -50dbm, and you also have another signal which bounced off a building, then goes to the receiver at say -53dbm to -60dbm, the radio will have some trouble. Especially because the signal with a reflection has additional phase shift. As the reflected signal wander from -53 to -60, there will be times when the reflected signal is captured by the receiver and times when the line of sight signal is captured. When it changes there will be a change if phase shift which often looks like FM modulation. If any reflections bounce of a building and is with in the 6dbm window, the radio is going to hear a bunch of noise, and will not be able to distinguish good data vs bad data.

Things that help include a good ground plane, and high elevations, but antennas in the same vertical orientation. You get many bounce paths off the physical ground, elevation helps avoid these issues. Also a good ground plane which is located above he real ground is good. So mounted on a piece of metal with the antenna poking straight up. The SMA connector should have a good ground connection to the metal. Even an alligator clip from the connector to the metal will be helpful. As long as it's grounded your antenna will be better. This hold true for both ends of the connection. If you can put a large metal plate on top of a pole, for the fixed station, that will be helpful.

Also helpful is a yagi, however beware they are direction, and you want like 2 or 3 elements, not 25 elements. AKA the below is way to directional, you want less elements, for a wider angle.

http://www.ebay.com/itm/RP-SMA-2-4GHz-25-DBi-Yagi-Wireless-WiFi-Antenna-For-Modem-PCI-Card-Router-FH-/162426936895?hash=item25d1665e3f:g:xWYAAOSw0HVWEylQ
Welcome to the friendlier side of internet crazy :)
User avatar
kb1gtt
contributor
contributor
Posts: 3758
Joined: Tue Sep 10, 2013 1:42 am
Location: ME of USA

Re: track telemetry - data radio

Post by kb1gtt »

Oh, also if you get the yagi for the base station, and it has a gain that is too narrow, you can make it wider by cutting off the extra director elements. I would think you want the driving element (loop with coax connected), reflector (back element), and perhaps 2 directors. See below graphic for my suggestion on what to cut off. This can be cut with a hand saw, it does not have to precise or pretty.
s-l500.jpg
s-l500.jpg (31.63 KiB) Viewed 17592 times
The antenna on the car if it has a good ground plane, will radiate and receive something like this. Notice that it would hear reflections from the back side as well as the front side. Notice this is about 5db in all directions.
0900aecd806a1a3e_null_null_null_08_07_07-05.jpg
0900aecd806a1a3e_null_null_null_08_07_07-05.jpg (140.34 KiB) Viewed 17592 times
The yagi with many elements will have a pattern something like this. Notice that's 15db forward and -10 in the reverse. As well it's 10db in a 50 degree window forward.
0900aecd806a1a3e_null_null_null_08_07_07-11.jpg
0900aecd806a1a3e_null_null_null_08_07_07-11.jpg (146.35 KiB) Viewed 17592 times
After trimming it down as I suggest the yagi gain pattern would be wider, and with less gain. So you are likely going to get like 10dB forward and -5 in the reverse, but instead of a 50 degree window, you'll get more like a 90 degree window. The gain helps with long distances. AKA the datasheet's claimed 20 mile distance is likely with a yagi on the transmitter, and another on the receiver, both pointed at each other. However if your target is moving around, and you drive the transmitter into a low gain area of the antenna, your going to have problems. So you need gain, with a wide angle, such that you have enough gain where ever you are on the track.

You do not need to trim all the elements I suggest, you could try trimming them one a at a time at the track. Such that you do not trim to many of them. Once you trim them they are gone and you can't put them back easily.

If someone wanted to simulate the antenna to see how the gain pattern changes as you cut off the elements, you could simulate it with 4nec2
http://www.qsl.net/4nec2/
Welcome to the friendlier side of internet crazy :)
Post Reply