Mobile HF questions

  • Hi Guest, you may choose a LIGHT or DARK theme that works best for you with the "Style Chooser" button at the bottom left on this page!
  • HTML tutorial

WUzombies

Rank V
Member
Supporter

Advocate II

2,261
Central Texas
Member #

0703

After the GNE last month I'm thinking about testing up and putting a mobile HF rig in the family adventure van. I know a couple of you have experience in such things and I wanted to know if I was barking up the wrong tree.

During the GNE the 2M communications between members of our group went really well, unless we had any distance between us (obviously). In the eastern part of central Texas in which I live communications over surprisingly long distances using 2M simplex is attainable, in the mountains of Wyoming, Montana, Utah and Colorado we had some issues. Repeaters filled the gap for most except in the national parks themselves, coverage (as I found it) was significantly lacking. We could put up a temporary repeater at camp, but even then we wouldn't have good line of sight for the signal in many instances. So the thought is to test up and go HF for group communications outside of line of sight, using (perhaps) 40M with someone in a stand off position (back in Texas?) in case of emergencies.

An example is that my family and I headed back towards camp in Lizard Creek to start cooking dinner (northern Tetons NP) while the other family and friends were visiting some spots in southern Yellowstone NP. We lost comms after about 2 miles of separation due to terrain. Is that too close to get a vertical bounce using something like 40M? As I understand it the terrain would eliminate ground wave just as the VHF/UHF was interrupted, we would be too close to each other for a typical propagation bounce but depending on the antenna design it could work with a near vertical bounce back towards the surface. If that understanding isn't correct, I would really love to learn why it isn't, or what your suggestions are. I'm looking at a Yaesu FT-857D, some of the local HAMs on the popular repeater suggested an auto-tuning motorized antenna, I was thinking about the big coil long whip design I've seen in my travels for a higher level of ruggedness, but to be frank I don't really understand which would be better fit to work through our minor difficulties.

If you're curious the campsite was here: https://goo.gl/maps/8nNkVMRTUv92 and a good reference point would be Lewis Falls in southern Yellowstone. Another example would be Logan's Pass to Fish Creek Campground in Glaicer NP.
 
E

expeditionnorth

Guest
there is no simple answer to this given propagation that changes ever so frequently & sadly the bands have been hit or miss depending upon the muf (maximum usable freq)
dont want to be the devils advocate here, not my intention
I have ham friends that I communicate with regularly up & down the state maybe 50 to 100 miles apart & we face your dilemma
each band has its range limits & the problem I foresee is how does the other party know what band to operate on
lets say for example I'm on 7.255 & I want to talk to my friends down the road 40 miles in Mt tabor 40M or 7.255 is useless during the day time, since they are in the skip zone & we cant hear each other .
however the guy in kentucky hear both of us
ground wave is limited given VT's mountainous topography (my qth) like where you talking about is about the same
a better band would be 80M
you seem well versed in this, maybe this will help ~ https://www.arrl.org/files/file/Technology/tis/info/pdf/8312011.pdf

for hf antennas I adore he texas bugcatcher antenna though it doesnt work for everyone
its larger diameter wire antenna provides some slight gain over screwdriver style antennas
 
  • Like
Reactions: KyleGrant

jerdog53

Rank V

Enthusiast III

1,655
Mobile Alabama
First Name
Jerry
Last Name
Moran
Ham Callsign
KD0ZDX
Might I suggest you tree top an antenna at your base camp and still use 2M, something like a J pole oriented with the optimum direction unobstructed.
 
  • Like
Reactions: WUzombies

WUzombies

Rank V
Member
Supporter

Advocate II

2,261
Central Texas
Member #

0703

The local repeater guys had a neat idea: HF packet radio for text messaging (of sorts), my thought is to
Might I suggest you tree top an antenna at your base camp and still use 2M, something like a J pole oriented with the optimum direction unobstructed.
That was the first thought, but it was ruled out for functionality issues. On this trip we encountered some of the worse topographic conditions for VHF/UHF you could come up with, a base camp repeater wouldn't have helped us at all unless we could have put a tower around or above 500ft AGL in camp.

One of the HAMs who hangout on the local (to me) repeater suggested HF based radio packet. I could setup my home system to run as the packet server and use a small laptop or (my exciting to me) build a custom application using Raspberry Pi and a mobile HF radio. Any of you guys run any of the mobile packet gear? The concept is still quite generalized and vague as I begin research into the different systems and I would love any guidance in regards to this or anything else really.
 
  • Like
Reactions: WJ - Firefly

Mad Garden Gnome

Rank V
Member

Off-Road Ranger I

2,771
Templeton, Ca
First Name
Ryan
Last Name
Marlett
Member #

661

Ham Callsign
W6ORV
Case in point. Driving home from work last night in coastal Central California, I picked up Utah and Nebraska stations on AM radio.
 

KD7WCD

Rank V
Founder 500
Member

Off-Road Ranger I

1,828
Tempe, AZ, USA
First Name
Jayson
Last Name
Adamsen
Member #

399

Ham Callsign
KD7WCD
The local repeater guys had a neat idea: HF packet radio for text messaging (of sorts), my thought is to

That was the first thought, but it was ruled out for functionality issues. On this trip we encountered some of the worse topographic conditions for VHF/UHF you could come up with, a base camp repeater wouldn't have helped us at all unless we could have put a tower around or above 500ft AGL in camp.

One of the HAMs who hangout on the local (to me) repeater suggested HF based radio packet. I could setup my home system to run as the packet server and use a small laptop or (my exciting to me) build a custom application using Raspberry Pi and a mobile HF radio. Any of you guys run any of the mobile packet gear? The concept is still quite generalized and vague as I begin research into the different systems and I would love any guidance in regards to this or anything else really.
If you are looking to pass packet data (Like text messages) you might read up on APRS. One of the neat things is that you can rely packets through other stations. The trick is there had to be other stations that you can hit to rely through and other than fixed weather stations and digipeaters this can be hit or miss. Kind of depends on who is in what area and has an APRS rig turned on.

Sent from my GT-N8013 using OB Talk mobile app
 

KD7WCD

Rank V
Founder 500
Member

Off-Road Ranger I

1,828
Tempe, AZ, USA
First Name
Jayson
Last Name
Adamsen
Member #

399

Ham Callsign
KD7WCD
there is no simple answer to this given propagation that changes ever so frequently & sadly the bands have been hit or miss depending upon the muf (maximum usable freq)
dont want to be the devils advocate here, not my intention
I have ham friends that I communicate with regularly up & down the state maybe 50 to 100 miles apart & we face your dilemma
each band has its range limits & the problem I foresee is how does the other party know what band to operate on
lets say for example I'm on 7.255 & I want to talk to my friends down the road 40 miles in Mt tabor 40M or 7.255 is useless during the day time, since they are in the skip zone & we cant hear each other .
however the guy in kentucky hear both of us
ground wave is limited given VT's mountainous topography (my qth) like where you talking about is about the same
a better band would be 80M
you seem well versed in this, maybe this will help ~ https://www.arrl.org/files/file/Technology/tis/info/pdf/8312011.pdf

for hf antennas I adore he texas bugcatcher antenna though it doesnt work for everyone
its larger diameter wire antenna provides some slight gain over screwdriver style antennas
Check out NVIS Antenna and propagation. Not something you want to do mobile but you can home brew an antenna fir a few bucks and they are simple and quick to set up. Great way to hop over a mountain range.

Sent from my GT-N8013 using OB Talk mobile app
 

KyleGrant

Rank III
Member

Off-Road Ranger I

662
Wichita, KS
First Name
Kyle
Last Name
S
Member #

2565

Ham Callsign
KSØTOR
I'd definitely be interested in a mobile packet configuration. I myself am just looking at bumping up to General so I can work HF while we're on trips, there was a cool contest called National Parks on the Air I found this year but the idea of working some digital modes from the truck would definitely peak my interest.

As for your communications dilemma, if you guys are traveling together - why be so far apart so 2M or 6M wouldn't be effective? During storm chasing, which has become severely crowded on the roads I might add; the popular item is 146.550 on simplex and we generally don't have any issues for miles. However, a suggestion may be if you're running three or more rigs at some major distances to configure your middle rig with a simplex repeater to reach either end of the convoy. Another option is to leap frog your convoy a bit. Lead vehicle traverse over higher terrain, sit at a peak while the second vehicle catches up, second vehicle stays at the peak while lead continues and tail continues to the peak, tail reaches the middle vehicle at the peak, middle continues and tail stays at the peak until the next peak. May be an idea to maintain a bit more 'line of sight' on 2M/6M for some rugged terrain. Just trying to understand your needs further, I don't mean to question your tactics.

I think for my purposes we'll be looking into a mobile NVIS antenna to get over some terrain, I still have a ton to learn on the HF side of things...