Amateur Radio in Airstream

[frjeff]

Originally Posted by AI7R

We just picked up a new Basecamp. Not much room but I'm still planning to have a station available. I've tested a Buddipole and it works pretty well. Even at 15 watts (Elecraft KX3) I've worked people reliably on 40 meters. My only worry was wind pushing the whole antenna over so I devised a very simple way to hold it down. I took a 3 foot chunk of aluminum angle and drilled a single hole in it on one end that a bungy cord hook would hook to. When I set up the Airstream I simply place the non-hole end under one of the jacks at the back. When I set up my antenna I place the center of the tripod over that hole and bungy it down tight and it's not going anywhere. I tried it and had it up for 4 days while changing the antenna configuration once in a while to see what worked best. I was receiving pretty well with all of them. Good luck and have fun! Dave, AI7R Chandler, AZ

Good idea!

[ke6gkv]

I've used both a 4btv on most of my ASs. Currently use a hygain 10-80 vert,standoff mounts on the jack.100 ft1/2 braided flat wire as extra counterpoise. Vhf and uhf i remote as needed.kurt

[frjeff]

Anyone tried one of the Alpha No Tuner vertical whips??

[uncle_bob]

Hi

One "cute" approach when using a conventional trapped vertical: Get the base up off the ground with a piece of pipe. In the case of a hitch mount on an AS, this also can get the base above the trailer. The advantage is that you move the high current (and thus high loss) part of the system away from the questionable / lossy earth ground. You also impact tuning when you do this, it will take some fiddling. I would not trust a setup like this in high winds, but it's not going to be up 365 days a year in most cases ....

Bob

[GM Airstream]

Originally Posted by frjeff

Anyone tried one of the Alpha No Tuner vertical whips??

Yep... and like the bed springs antenna they work about the same...

I did a lot of study'n on the subject years ago.. and wrote a article that you can find in eham... on putting the 5btv on the back of the AS. Depending on the size trailer you have... makes the ground plane or not... putting radials out the back is nice but... if your in a park that others back up to you... you know the drill...

About the only thing you can do in close quarters... is to have the radio mounted mobile in the TV and not the trailer...

As to punching holes in the trailer... you can use the A frame on the front.. or use the frame at the back before the bumper... their you can put some holes to mount a mount that then the antenna mast can be mounted to.

I would not use the jack post on the A frame as it is not that structurally strong... but, instead use a mount that is similar to the sway control which has U bolts and plate that mounts on the trailer frame..

I have seen one that they used bolts through two plated that went around the one side of the A frame... the two plates then have the square tube mount... that then the antenna post can be plugged into and seems to be strong enough to go up 40 ft... etc...


Don't think that a vertical.. can work without a ground plane... its the other side of the antenna...

Run'n the coax... either under the trailer pan or feed it through the inside at the wall bottom... Most have used adel camps that they screw to the hard points along the underside of the trailer... which then turns up and comes through the floor... where the radio is going to be located...

Also you don't want to use the AS inverter as power for the radio.. way to noisy... as well as anything .. like the heater comes on.. you can't get away from spikes... so you want to use a good astron and/or switching power supply that is large enough for the radio... and forget the bats except when your out boondocking off of shore power...

Too bad the high serr 1800 pro is not made any more... it was a great mobile all band antenna... and by putting a hitch on the one side of the rear of the trailer.. you could get a post that would put it at the base of the roof line of the trailer.. they then work pretty good... and when ready to travel you could take it down.. put it on the TV and use it while going down the road... not to mention that most radios can be opened up so they cover the CB band.. which then the HS 1800 would tune too.. leaving it to one antenna for HF... and one for UHF/VHF... such as a mag mount...

Good luck.. go look at the article I wrote back in 1973 that I revised on eham recently...
Look up my call on articles written on eham
WA6CDE

[k0lw]

I have used both Hamsticks and Hustlers on the rear bumper with good success on 40 & 20. I recently installed a Hi Sierra RV screwdriver antenna on the jack post. Seems to work quite well except a shorter top whip will resonate on the higher bands (17 & up). I ran the coax thru the inverter vent at the front of my old 78 AS. I also run coax (RG58) thru the refrigerator vent door for satellite and other antennas.

I have a short UHF/VHF dual band antenna on the roof where the leaking TV antenna used to be.

IC7000 is perfect rig for HF thru UHF in my AS.

Now I'll try to post a picture. ....1st time on the forum .... ..

73, k0lw

[frjeff]

Originally Posted by k0lw

I have used both Hamsticks and Hustlers on the rear bumper with good success on 40 & 20. I recently installed a Hi Sierra RV screwdriver antenna on the jack post. Seems to work quite well except a shorter top whip will resonate on the higher bands (17 & up). I ran the coax thru the inverter vent at the front of my old 78 AS. I also run coax (RG58) thru the refrigerator vent door for satellite and other antennas.



I have a short UHF/VHF dual band antenna on the roof where the leaking TV antenna used to be.



IC7000 is perfect rig for HF thru UHF in my AS.



Now I'll try to post a picture. ....1st time on the forum .... ..



73, k0lw

Would love a picture. If you cannot post, my email is frjeff@gmail.com

[frjeff]

Originally Posted by frjeff

Would love a picture. If you cannot post, my email is frjeff@gmail.com

Can someone here tell me how to best ground my equipment inside the Airstream??
Thanks.

[GM Airstream]

Originally Posted by frjeff

Can someone here tell me how to best ground my equipment inside the Airstream??
Thanks.

Yep... use a No. 10 or larger stranded piece of wire... and go down to the frame... then also run the same piece back up and attach it to the body at one of the openings...

The reason why is because the frame is one thing.. the body is attached to the wooden floor... and sometimes not grounded as good...

You need not ground the radio.. if you use coax... to the antenna... as you only need the other half... ground side ... will be terminated at the antenna and not the trailer body...

[uncle_bob]

Hi

The AS it's self is a great big chunk of shielding. Connecting to the shielding is a little complicated. Since it's aluminum, just bolting a cable to it will generate corrosion (unless it's an aluminum cable). There are various paste materials made for coating junctions like this.

My favorite approach for any operating position is to set up some sort of bus bar at the back of everything. Then all the gear gets grounded directly to that bar. That way there are no sneaky voltage differences between this and that piece of equipment. I like copper strap for taking the bus bar to a "real" ground. In this case it would be the trailer frame / shell.

The "why ground" thing is open to a lot of debate. RF flying around bothers some more than others. Certain gear is more bothered by this or that. Things like lightning do happen from time to time. Having everything tied together will reduce the damage from a hit in the vicinity ...

Grounding the trailer it's self is a bit interesting. A ground stake is the "approved" approach for lightning. Good luck with that after about three trips out The campsite water pipe is an "interesting" alternative. How happy the rangers will be about a cable connected to it ... who knows. For RF, a metal screen tossed onto the site (like under the rug or the AS) probably will do as well as anything else short of radials.

Bob

[GM Airstream]

The AS it's self is a great big chunk of shielding. Connecting to the shielding is a little complicated. Since it's aluminum, just bolting a cable to it will generate corrosion (unless it's an aluminum cable). There are various paste materials made for coating junctions like this.

If you run the coax along the underside of the trailer you can use rubber/silicon insert adel clamps like I did.. then you don't have any problem of the coax cable causing corrosion... or what ever... as its somewhat insulated away from the metal by the rubber/silicone insert... they come that way...

Also... as to ground loops... if you don't ground the radio through the framework... or body.. but instead terminate the coax at the antenna with a choke balun.. you won't have any problems with RF getting back to you...

Just a little something we learned through the years... with A/S.

Next comes where to place the lin amp... as we have seen several that made up for bad antennas that use them... gives a whole new meaning to QRP and low power...

[rmkrum]

Heh, I’ve always claimed life is too short for QRP...unless you are doing PSK-31....at about 20 Watts to reach around the world!

[uncle_bob]

Originally Posted by GM Airstream

The AS it's self is a great big chunk of shielding. Connecting to the shielding is a little complicated. Since it's aluminum, just bolting a cable to it will generate corrosion (unless it's an aluminum cable). There are various paste materials made for coating junctions like this.

If you run the coax along the underside of the trailer you can use rubber/silicon insert adel clamps like I did.. then you don't have any problem of the coax cable causing corrosion... or what ever... as its somewhat insulated away from the metal by the rubber/silicone insert... they come that way...

Also... as to ground loops... if you don't ground the radio through the framework... or body.. but instead terminate the coax at the antenna with a choke balun.. you won't have any problems with RF getting back to you...

Just a little something we learned through the years... with A/S.

Next comes where to place the lin amp... as we have seen several that made up for bad antennas that use them... gives a whole new meaning to QRP and low power...

Hi

RF back from the antenna is only one issue. A lightning strike may or may not behave nicely. You have the shore power line, the antenna, and who knows what else going who knows where. Tying stuff together is still a good idea.

Bob

[frjeff]

Originally Posted by uncle_bob

Hi



RF back from the antenna is only one issue. A lightning strike may or may not behave nicely. You have the shore power line, the antenna, and who knows what else going who knows where. Tying stuff together is still a good idea.



Bob

Indeed! Just not always easy or possible in RV parks.

[OwnerAt19]

Originally Posted by uncle_bob

"the 'hot step' problem"

I think that I might have a guess, but just in case, ... what is the "hot step" problem?

de W6NCT

[OwnerAt19]

[I posted a longer version of the following reply, detailing my thoughts and experiences for antennas and mounts; but the AirForums web-site timed-out on my login, and also hung when I submitted it; and appears to have lost it, TWICE!!! UGH!]

In any case, the Reader's Digest (summary) version is:

• MOUNTS:
  • I've used small pipe connected to tongue-jack to hold a 10-ft mast with pretty good success (especially for VHF/UHF omni antennas, like GP6).
  • I've also used a mounting base that goes under the tire of the trailer (or vehicle) with a lot of success. I built mine; but you can buy pre-built ones like this from several sources.
  • I also have a general-purpose antenna mount on top of my AS, just aft of A/C. In the past, I've had to climb up to reconfigure (or tip down/up for travel); but I plan to change this to a more permanent UHF/VHF (mobile-type) omni. Right now, it's (RG8) coax goes in through the refrigerator vent, to a handy connector mounted in the (center BR) vanity of my AS.
• ANTENNAS:
  • I've had good luck with various UHF/VHF omni-directional antennas, including those intended for mobile use (sometimes with add-on, base-mount radials); and even larger antennas (e.g., Comet GP6, or equivalent).
  • For HF, for years I have used a long-wire, using a ICOM AH4. I extend it up using a 32-ft, fiberglass, heavy-duty, extendable pole. These poles are typically sold for use with RV windsocks; but they do well to get a major portion (of 24-28 AWG) wire upright, then I extend the tip off to a convenient tree (if/when available). The vertical section is omni-directional; but the horizontal section is direction (toward tip), to give a flexible pattern.
  • I'd also recommend portable directional antennas like Buddipole, and rotatably dipoles using a pair of ham-sticks. These can be used with the (under-the-tire) mount described above.
  • My Dad (sk) used a Hustler mobile antennas for HF (with interchangeable coils) for years, with a lot of success; but I have yet to try it with AS.
  • I've also known people that have used screwdriver antennas (e.g., High-Q) with lots of success.

.. I hope this helps.


de W6NCT

[frjeff]

Thanks for all of the great tips and suggestions! Think I am going with the 27’ Zerofive Multiband mounted to a 1.5” pipe mast welded to the rear curbside frame member that extends out to the bumper. This will be dead center of the rear tail light and just below it. Only deployed when stationary, of course.

[uncle_bob]

Originally Posted by OwnerAt19

I think that I might have a guess, but just in case, ... what is the "hot step" problem?

de W6NCT

Hi

Earlier in the thread, I mentioned grounding HF vertical antennas to the AS. The gotcha is that the AS is not really *at* ground relative to the earth. The net result could be a "hot" (at RF) trailer body. The example was a bit of energy transfer to somebody getting into or out of the trailer while you were transmitting. That morphed into "hot step" ...

Bob

[GM Airstream]

ad

Originally Posted by frjeff

Thanks for all of the great tips and suggestions! Think I am going with the 27’ Zerofive Multiband mounted to a 1.5” pipe mast welded to the rear curbside frame member that extends out to the bumper. This will be dead center of the rear tail light and just below it. Only deployed when stationary, of course. :)

NO NO NO... never weld anything to the AS trailer frame... it goes without saying that you will introduce stress and embrittlement... if you do...

Instead.. bolt where possible... a welded item to it... instead...

Also.. don't place anything that is going to stay in place which will restrict the viewing of the tail light...

I think I sent you drawings of the way I did mine... and how it clears all the important things like the storage lockers.. etc...

No welding on the AS frame please... not good...

.. oh and AS trailer body is grounded when plugged into shore power...

[hendy]

I'm going to go a different direction in my answer.

I use a ~104' "end-fed dipole" (see QSO-King). I have a mast that goes up 42' and I guy it to my trailer. This inverted-V configuration does very well, and better if you use an alligator clip to ground the AS electrically, somehow. The mast, in turn, consists of the 48"x2" military pipes, into a tripod.

The same is used on Field Day.... and is powered by marine batteries and a solar panel, which keeps it electrically isolated from an inverter/shore power, etc. Not much real estate is used, and it's pretty stable, high in the air, and good from 80-6 with any old tuner.

Takes a short while to put up, but guying is very simple, and if you put an LED on the top, it's a beacon to find your way home after dark

73 de W9YW Tom