Baja Mexico Antenna help??

[smithpa68]

Hi all. New to the forum. I am trying to find some help and advice for purchasing antennas for my chase vehicles for this year's Baja 1000 race in Mexico. I intend to purchase some Yaesu 2900 VHF radios (yes they are cheap... but pulling off the Baja 1000 from clear across the country is EXPENSIVE! I need to have reasonable costs where I can) and need some advice on antennas.

My basic requirements are:

-100w output
-144mhz to 160mhz. Most Baja race freqs are 150 to 158mhz so that is my primary range if I need to narrow it down.
-Magnetic mounts or some simple way to mount them that will do no damage to my rental chase vans. I can't be drilling holes in them and I need to pull the equipment off the vans at night while in Mexico so it doesn't get stolen.
-Needs to be durable since we are chasing across really rough terrain for 1000+ miles.
-Looking more for horizontal range is priority. I am not going to be sitting on a mountain for the race. We are traveling the distance of the whole Baja California peninsula.
-Prefer something that doesn't need tuning. I am not going to have time or equipment to play with that. It would be fun at another time, but not for this event.

Any help and advice would be much appreciated by the team.


Scott
DirtBikeBucketList.com

 

[BonziBuddy]

Google MHB5800S and B1443S. They're 5/8 wave high gain antennas which have springs to prevent being snapped.

Then get an Antenex G8 magnetic NMO mount. They attach right onto them.

 

[rfradioconsult]

As a side note, your 100W radios cannot be powered by the cigarette lighter receptical or any accesory type plug, you will need a direct connection to the battery, a 100W radio will draw about 25-30 amps on transmit.

 

[smithpa68]

Thanks. I definately planned on wiring it to the battery of the vans. No problem there. Appreciate the advice and tips.

 

[prcguy]

The two antennas mentioned are good along with their Larsen counterpart but they will require cutting to length and preferably a tune up They also are narrow band and once you get about +/- 2MHz from the tuned spot they will loose performance.

The 100w VHF radios I use only draw 18-20A on transmit but most cig lighter sockets will probably not handle that with an FM radio.

At best your distance on VHF hi band might reach 75mi or so mobile to mobile and its good to make friends with ham radio operators who can provide HF comms which will cover the entire area.
prcguy

 

[W6KRU]

Hi Scott, Whatever you do, make sure the Weatherman doesn't find out about your use of the ham radios on race freqs. At a minimum you'll get his lecture and at worse he won't answer you on the relay. That is good advice from prcguy, with the exception of getting mexican hams to help you. As he says you should attempt to cut the whips for whatever freq. you are going to use. See if you can find a ham in your local area to help you with tuning the antennas.

I understand your budget issues but you might want to have a few spare antennas for the chase and race rigs because it is baja and if one gets torn off, you won't be able to obtain a replacement.

All of the chase teams should get a little class before leaving. Explain to them that they should always seek out some high ground when attempting to communicate. Don't sit in the bottom of a wash wit 30' walls on both sides. Drive out of the wash and find at least a small plateau to work from. Good luck and have fun.

Add: Put adhesive labels on the dash of all vehicles with your race frequency in case you need relay. Ch1 means nothing to the guys running relay.

 

[smithpa68]

Thanks Dan. I am not sure why weatherman would care. Sounds like a lot of folks do it this way. But I will heed your advice. Never know when he might be the only link you have to the rest of the world.

I will definately have some training for the chase crew. Two of our guys are already licensed. One is a paramedic and one is a private pilot. I have a print out of the race frequencies already that we can tape to the dash of the van.

The comment above about tuning +- 2mhz and it drops off, is there any way to avoid that? I want to be able to hit several frequencies in the 150 to 158 range. Is there a choice that makes this performance hit less of an issue?

 

[W6KRU]

The Weatherman is Bob Steinberger. He owns PCI Race Radios and he does have valid points about people using ham radios and causing interference to other crews on race frequencies. I would bet that over 90% of the radios used in the Baja 1000 are from PCI.

The 5/8 wave antennas that are discussed above are narrow banded due to their design. It is a trade off in design that you can't do anything about. They don't stop working when operated outside the bandwidth, they just don't work as well.

 

[prcguy]

I just looked up the 7900 and its a 75w radio. Anyway, they are being used in Mexico where US regulations do not apply and a 7900 is not going to interfere with another radio any more than any other radio. Bob will not be happy you are using them mostly because he didn't make a sale.
prcguy

 

[smithpa68]

Ahh. I see said the blind man from the east coast. Thanks for the tip. I will make sure the team has good instruction and spends 99% of their time listening. No goofing off on the air down there.

So, for 150mhz to 158mhz... shouldn't be a problem with these antennas? What sort of % degradation are you talking about? I am probably worrying too much about it. Right?

 

[smithpa68]

I just looked up the 7900 and its a 75w radio. Anyway, they are being used in Mexico where US regulations do not apply and a 7900 is not going to interfere with another radio any more than any other radio. Bob will not be happy you are using them mostly because he didn't make a sale.
prcguy

Minor correction it is a 2900. I can understand him being upset with people over powering and jamming things up with poor ettiquette. I would think that as long as the crew knows how to behave on the air.. we shouldn't have a problem.

Quite unexpected to find Baja guys here. Good stroke of luck for me. Your advice is very much appreciated.

 

[W6KRU]

One of Bob's complaints about ham radios is that they aren't "channelized" and people can tune them to any frequency. This results in crews picking frequencies that that fall in between 2 proper frequencies thus hosing up two channels at once. The other has to do with the quality of the microphones which result in too many "richard craniums" with open mics who disrupt the use of the relay frequencies. Don't shoot me I'm just repeating what I've heard. :lol:

 

[smithpa68]

That makes a lot of sense. I understand. I will make sure our guys do not just pick a "quiet frequency" to chat with each other. Is there a way to submit a request to be assigned a frequency for the event?

For our purposes, we really only want to listen to Weatherman and contact our pit service but it would be nice to have a place for our chase crews to keep in contact without cluttering up the pit service frequency. There will be many times where there are close enough to talk to each other as we leapfrog down the peninsula.

 

[W6KRU]

The only way that a frequency is assigned that I am aware of is when you buy a PCI radio. Their list of frequencies is not published anywhere that I am aware of. i could take guess after looking at my list but it would only be a guess.

It is no big deal to share a frequency with another team as long as you always listen for a bit before transmitting. If you do "intrude" on someones frequency and they are in the middle of something, they will let you know. A good way to deal with that is to have two frequencies set up for your use. If chase 1 calls chase 2 on channel 1and gets back a gruff "channel is in use", chase 1 would reply with "sorry, chase 2 go to channel 2". It is always a good idea to use no more power than you need. If 2 chase crews want to chit chat and are only a couple of miles apart, do not leave the radios on the 75 watt setting.

You should program the frequencies you are going to use into memory so that they can be easily accessed in a vehicle bouncing down the road. I would do something similar to:
Ch 1: Pit crew you are using
Ch 2: Weatherman
Ch3: Your race freq. 1
Ch4: Your race freq. 2

The chase crew should be able 2 operate the radios without having 2 think about it. They don't want to be reading the operators manual while on the road looking for the other truck in the middle of the night. They should be very familiar with radios before heading to baja.