Pondering 6 Meters Mobile

[tweiss3]

I have a few road trips this summer planned. We will be taking my wife's vehicle.

Transit Connect. Currently there is the primary 2m & 70cm (50 watts) antenna in location 1, and the scanner antenna in location 2. Between the scanner antenna, the primary radio (50W dual band) and roof luggage carrier.

I was tossing up the idea of temporarily adding 6m to the car for a few road trips via 705 or 817 (10W max). I've thought of getting a tri-band antenna for location 1, but I can't find one I like or would trust for the whole trip. The Diamond/Comet options look problematic. Based on my research, the Larsen NMO50 whip is only good for 6M, not good on 2M or 70CM, while the NMO140 is good on both 6M (accidentally) and 2M, but not 70cm. I can't loose 70cm, as we will be using that for general convoy communications in the mountains.

My only real option is placing a third antenna (likely NMO50) 20-22 inches from the dual band radio antenna, on the passenger side. While I'm not necessarily worried about the 10W of 6m getting to the other radio (or affecting its ground plane), I am worried about the 50W radio blowing through the front end of the radio used on 6m, even if it isn't resonant on those frequencies.

What are my options? Annoyingly enough, all the 6m bandpass filters I find are only good for 50-52MHz, where half the intended use is above 52MHz. Also, what is the usable bandwidth of the NMO50, I don't see anyone mentioning that in the specs, though the cut chart indicates it might be pretty narrow.

Second, and less ideal option would be to mount a MFJ MFJ-1606T 6M whip on the hatch, attached at the lower part of the hatch, and supported near the top, of the coil, below the whip part. The scanner scanner antenna should be protected as it has an RF limiter, but I don't want to pop that limiter, I think it's rated for 10W max.

[kidphc]

Personally, been tossing the idea of a second antenna on a tilt (motorized mount) for an ID 5100a. Here is what I kinda have come up with.

Currently, the ftm400 is connected to an antenna on a hood mount. I have a ditch light bracket on the rear driver corner for a 10m/11m antenna.

I have thought for a second ditching the 10/11m putting a little tarheel with ic705a and a diplexer to both to a the motorized 2m/70cm antenna and the tarheel. Problem is this will cost almost 2k.


Point being, have you considered using a hatch mount and maybe a small screw driver with a diplexer to another antenna? Seems like you would be gimping yourself and the radio by limiting it to 6m. Negative outside of cost would be that it would be more of a permanent install.

Sent from my SM-G975U using Tapatalk

[marcspaz]

This is just my personal opinion.  Unless you have a mobile high gain / beam antenna setup and plan on working world-wide FT8 while mobile, I wouldn't waste 10 cents on a 6m mobile.  In the 20+ years I have been in radio, I have made exactly 1 voice contact on 6M that was past LOS.  If I count FM repeaters, there were 2 contacts in 20 years.  And even with 100w, my LOS is legit about 2.5-3.5 miles around my home.

 

If you really want to talk while noodling around... get a 20m or 40m mobile.  20m is fantastic as far as users and mobile antenna efficiency, but fades faster after sunset than 40m.  I personally have the ability to run everything from 160m through to GMRS in my Jeep, with only 2 radios and 2 antennas, swapping mono-band HF antennas depending on what band I want to work.

 

If you really want to do it anyway, I would use 2 radios and antennas. Put the 6m antenna in spot 2,using a UHF mount and a Diamond HF6FX Monoband Mobile Antenna.  Out of all the mobile antennas I have used, this is the one that I had the best luck with.  Its the only antenna I made a long distance voice contact with, and on FT8 I worked 40 countries when the conditions were good.

 

Also, unless you are going to keep power around 5w, you're probably going to have to keep whatever radio you are not using, off while talking on the other.

 

If you want to do it all with 1 radio and 1 antenna, get a Yaesu 8900 (discontinued radio) or a clone of it, and a Diamond CR8900A antenna.  It is pretuned to give best bandwidth and VSWR over the FM portions of 10m, 6m, 2m, and 70cm.  It's not really usable for the Data/SSB portions of the 6m band without a tuner.

[tweiss3]

@kidphc Yea, looking at Little Tarheel II/Baby Tarheel again. It would be an option for hatch lip mount.

@marcspaz Removing the scanner in position 2 is a non starter. That thing has gotten me out of so many headaches while traveling. Getting a screwdriver would add 6-80 instead of just 6. This is my wife's car, and the two antennas up there are nearly invisible, and I'm not really interested in swapping out radios, as she has the hang of this one, I don't need to muddy that water.

The idea of the third hole was I would trust it with a whip while on the trip, but then pull the antenna and cap it, not worry about anyone seeing it to tamper with. With a screwdriver, I could pull the antenna for the week, and reinstall for the return trip, but the whole mount would come out after, I don't need anything visible where one could tamper or have reason to mess with her car.

 

I never intended to play around on FT8 mobile or anything like that, but it would be nice to have a setup that could be used in the future for POTA. 

 

I think all this points me back to spending $600 on a screwdriver antenna. Height above roof line would be more desirable as well (XYL approal).

[kidphc]

[mention=2261]kidphc[/mention] Yea, looking at Little Tarheel II/Baby Tarheel again. It would be an option for hatch lip mount.
[mention=2213]marcspaz[/mention] Removing the scanner in position 2 is a non starter. That thing has gotten me out of so many headaches while traveling. Getting a screwdriver would add 6-80 instead of just 6. This is my wife's car, and the two antennas up there are nearly invisible, and I'm not really interested in swapping out radios, as she has the hang of this one, I don't need to muddy that water.
The idea of the third hole was I would trust it with a whip while on the trip, but then pull the antenna and cap it, not worry about anyone seeing it to tamper with. With a screwdriver, I could pull the antenna for the week, and reinstall for the return trip, but the whole mount would come out after, I don't need anything visible where one could tamper or have reason to mess with her car.
 
I never intended to play around on FT8 mobile or anything like that, but it would be nice to have a setup that could be used in the future for POTA. 
 
I think all this points me back to spending $600 on a screwdriver antenna. Height above roof line would be more desirable as well (XYL approal).

Don't forget an automatic controller, unless you are tuning stationary by ear. 300 or so.

A side benefit would be the coax connector could be use when camping etc. To throw up a wire or if your really keen on it a 1/4 multibander (dxcommander).

Really about how much you are going to use it and why.

Plus with the tarheel and extra cables it could be moved to your daily driver.

Sent from my SM-G975U using Tapatalk

[marcspaz]

12 minutes ago, tweiss3 said:

I never intended to play around on FT8 mobile or anything like that, but it would be nice to have a setup that could be used in the future for POTA. 

 

I think all this points me back to spending $600 on a screwdriver antenna. Height above roof line would be more desirable as well (XYL approal).

 

Ah, yeah, all that makes sense.  A third hole seems like the best option.  I have used screwdriver antennas on lip mounts while stationary, but I would not drive with it on one.  A solid body mount is really needed.

 

I have used a Little Tarheel 2 and a Diamond SD330 HF screwdriver.  They both work great.  I wanted to try the Baby Tarheel, but they are out of stock everywhere.  I can't even find another Diamond.