Author Topic: Portable HF antenna for emergency use  (Read 12360 times)

Offline Carl

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Portable HF antenna for emergency use
« on: August 11, 2016, 06:36:17 AM »
  During my years of experimenting with mobile antennas for HF (good for CB also) radio use and for remote/emergency use
I have found that a mirror mount and a cheap camera tripod makes for a pretty effective antenna for VERTICAL (best for DX)
use OR with a dipole adapter mount ,as a good NVIS platform for optimum 'local to 200 miles' use to work 'close in' for terrain
difficulties often encountered and better radio coverage in localized recovery/emergency use.

The 3/8 x 24 Ham Stick is good for non-tuner situations for single band use OR your single band antenna can cover many bands with
addition of an external antenna matcher ,ofren called and antenna 'tuner'.

Ham Stick example:

https://www.amazon.com/MFJ-Enterprises-Original-MFJ-1640T-Antenna/dp/B00KO6BQKI/ref=sr_1_17?s=electronics&ie=UTF8&qid=1470916862&sr=1-17&keywords=ham+radio+antenna+3%2F8+x+24

Mirror mount example:

https://www.amazon.com/Aluminum-Double-Groove-Antenna-Bracket/dp/B01CBYMH7G/ref=sr_1_19?s=electronics&ie=UTF8&qid=1470916862&sr=1-19&keywords=ham+radio+antenna+3%2F8+x+24

"Dipole mount" example

https://www.amazon.com/MFJ-347-HAMSTICK-DIPOLE-MOUNT-HAMSTICKS/dp/B00KGHZ2FU/ref=sr_1_11?s=electronics&ie=UTF8&qid=1470916862&sr=1-11&keywords=ham+radio+antenna+3%2F8+x+24

When used as a vertical,the antenna needs radials or counterpoise wires andI have found that a 17 to 17 foot 6 inch wire (a 1/4 wave for 20 meters) is effective on all bands except 6 and 10 meters  and will work for 6 and 10 meters when folded in Half. I use pre cut counterpoises to speed deployment and use gator clips on each end of each wire to clamp onto the antenna mount or for other antenna options such as a 20 meter dipole then clipped to a balun.

The 'dipole' adapter will do good NVIS with a misbalanced 40 meter and 80  meter stick and will do OK without a tuner BUT is better with an antenna tuner for radio safety and multi-band  use...
I prefer a LIGHT STAND for added height adjustment of the dipole setup  to get above head (and eye) height and have found 8 to 10 feet does well.

With an auto or manual matcher (tuner) I also use a fiberglass 20 foot fish pole and 34 feet ( two of the 17 foot counterpoises clipped together)of 18 gauge wire when a tree can't be found for a support and with a set of 2 or 3 of the 17 foot counterpoises get much better effectiveness for distance and the end of the 34 feet can hang as if fishing when the pole is mounted at a slight angle.

A few simple wires and hardware can provide one with a kit for many antenna options and provide flexibility for travel of after the storm use...one other handy gadget is the VICE GRIP MOUNT...

https://www.amazon.com/Vise-Antenna-Mount-PL-259-Cable/dp/B001JT5S3U/ref=sr_1_1?s=electronics&ie=UTF8&qid=1470918517&sr=1-1&keywords=vice+grip+antenna

and don't forget extra coax cables with connectors,tools,and plenty of wire for many options.

Budget 20 meter dipole


A home made 20 meter vertical ,vertical antennas work best when LOW to the ground and at least 3 counterpoises.

Offline Chemsoldier

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Re: Portable HF antenna for emergency use
« Reply #1 on: August 11, 2016, 06:51:46 AM »
 :popcorn:

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #2 on: August 11, 2016, 06:54:25 AM »
:popcorn:

You gonna' share that popcorn?

Antennas are the easiest and most bang for the buck option that even a slightly skilled person can build from few purchased items and often found wire.
I often build wire antennas as needed from a few accessories Baluns,PVC cut as insulators,and gator clips for pre-cut wires and adapters. Even a TAPE MEASURE
can ,and often is adapted as an antenna or counterpoise when needed (it has a gator clip attached to it too).
« Last Edit: August 11, 2016, 07:03:08 AM by Carl »

Offline Smurf Hunter

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Re: Portable HF antenna for emergency use
« Reply #3 on: August 11, 2016, 08:53:56 AM »
Something I picked up on a whim was a large magnet mount based with 3/8-24 threads.

I've used it with a CB firestick that I tuned to 10 meters, as well as a 5/8 wave 2 meter whip.
As far as gain, the 5/8 whip with the magnet base is so far is the best "mobile" VHF setup I've had.  The SWR meter is flat across the band too.

I'm interested to see how a 40m stick might work on this mount.  Maybe I can mount on a garbage dumpster for extra groundplane  :P

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #4 on: August 11, 2016, 09:08:52 AM »
Something I picked up on a whim was a large magnet mount based with 3/8-24 threads.

I've used it with a CB firestick that I tuned to 10 meters, as well as a 5/8 wave 2 meter whip.
As far as gain, the 5/8 whip with the magnet base is so far is the best "mobile" VHF setup I've had.  The SWR meter is flat across the band too.

I'm interested to see how a 40m stick might work on this mount.  Maybe I can mount on a garbage dumpster for extra groundplane  :P

While a mag mount is convenient,it does not provide optimum ground for ANY antenna...but I use and like them too. Your 40 meter or other
Ham stick antenna should work OK,though not terribly effective as tests show a 100 watts in with a Ham Stick produces a 5 watt equivalent
signal when compared to a simple vertical dipole at the same range from a field strength meter though still a good signal and even when compared
to a popular 16 foot BASE vertical antenna(that says it needs no ground radials) the Ham Stick is a near equal.

A field strength meter will compare antennas better at close range than any number of contacts,with exception of take off angle.

Lastly ,a single mag will NOT hold a 7 foot Ham Stick at speed...though ,with a good auto matcher,it will work for most HF Ham bands.

Offline Smurf Hunter

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Re: Portable HF antenna for emergency use
« Reply #5 on: August 11, 2016, 09:24:01 AM »

Lastly ,a single mag will NOT hold a 7 foot Ham Stick at speed...though ,with a good auto matcher,it will work for most HF Ham bands.

I read on that amazon page that magnetic mounts were not recommended.  I presumed that was stated more for safety than RF function.
I have a few 3/8-24 to so-239 bulkhead mounts I could fashion into a tri-pod or clamp style mount.

So much to try...

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #6 on: August 11, 2016, 09:45:43 AM »
I read on that amazon page that magnetic mounts were not recommended.  I presumed that was stated more for safety than RF function.
I have a few 3/8-24 to so-239 bulkhead mounts I could fashion into a tri-pod or clamp style mount.

So much to try...

The 3 magnet mount will do for highway speed though I still prefer the tripod or stationary operation with wire or whip
NOTE that a single 20-40-or 80 meter whip will work well for most bands with a tuner as the Ham Sticks are all the same 7 feet tall and only the base coil differs..
and WOLF RIVER COILS  offers a manually tuned coil that works well if you have an SWR meter rather than a tuner.


http://www.randl.com/shop/catalog/product_info.php?cPath=2000&products_id=39587&osCsid=80n6apjgkvgm1ougbdlgbniv93

Wolf River option,I don't suggest for mobile in motion

http://wolfrivercoils.com/products/mini_sb.php

Offline Canadian Prepper

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Re: Portable HF antenna for emergency use
« Reply #7 on: August 11, 2016, 10:04:19 AM »
Thanks for the ideas, Carl!

I picked up the MFJ 80m mini (hamstick) dipole but haven't used I much since my tripod only got it 6ft off the ground and it didn't come close to my W3EDP end fed when I last tried them out to compare. Earlier on I did make a contact on one of the local 80m nets with a single stick mounted as a vertical with some counterpoise wires, but it was a hard copy on the other end.

I've got an 18 foot telescoping MFJ tripod now and might try it again at that height with the dipole for comparison, or perhaps try a few other configurations in the vertical position (I've got 33 ft of copper wire that I'd considered using as a radial for a vertical to help on 40m). With luck I might even be able to mount one of these options on a balcony, etc., which hasn't been a realistic option for any of the full sized verticals (ie. Hustler BTV5, etc.) I'll report back on any findings.

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #8 on: August 11, 2016, 10:26:41 AM »
Thanks for the ideas, Carl!

I picked up the MFJ 80m mini (hamstick) dipole but haven't used I much since my tripod only got it 6ft off the ground and it didn't come close to my W3EDP end fed when I last tried them out to compare. Earlier on I did make a contact on one of the local 80m nets with a single stick mounted as a vertical with some counterpoise wires, but it was a hard copy on the other end.

I've got an 18 foot telescoping MFJ tripod now and might try it again at that height with the dipole for comparison, or perhaps try a few other configurations in the vertical position (I've got 33 ft of copper wire that I'd considered using as a radial for a vertical to help on 40m). With luck I might even be able to mount one of these options on a balcony, etc., which hasn't been a realistic option for any of the full sized verticals (ie. Hustler BTV5, etc.) I'll report back on any findings.

While height above ground is not a benefit for other than line of sight coms with a vertical as the vertical has best effect and radiation angle for DX ...Try using radials (counterpoises ) of 17 feet long and a foot or more ABOVE  THE GROUND to prevent ground loss as a counterpoise is way more effective when above ground.

Also,your single whip will mount sideways and can also use the 17 foot wire instead of a second whip if the support is stable or the counterpoise (or two)  are used as partial guy wires to support off center weight.

I made a 'jungle antenna...a dipole with 17 foot per side and the shield connected side has 3 17 foot wires so it works as a dipole,inverted "V" ,vertical dipole...or a GROUND PLANE with the tree support and three legs spread (hint ...the legs can orient to favor the direction they share  and do not need to be equal angles on each side..Keep putting the VERB in Ham buddy..

If you read this far , you get KARMA for effort.

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #9 on: August 11, 2016, 05:27:33 PM »
Another good little antenna is the MFJ 1622 Apartment antenna:
 
http://www.mfjenterprises.com/Product.php?productid=mfj-1622

and has proven effective for HF,this one modified with coax connector and counterpoise clip is an impressive HF performer and can be used without a tuner. With only a 4 foot whip it is a surprize as to how well it does work, I recently passed it  to DON and I will ask his for his comments on performance as he also has used it successfully.You manually 'tune' the antenna by selecting the best "noise" level with the coil clip and the tune by eear is learned through practice.


Offline DonC

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Re: Portable HF antenna for emergency use
« Reply #10 on: August 11, 2016, 05:39:45 PM »
As requested by Carl, here is my impression of the MFJ Apartment antenna. 1st, I want to thank Carl for this little, yet very powerful addition to my collection!

As stated elsewhere in the TSP forums, this antenna has performed far beyond my expectations. I set it up on the chain link fencell in Carl's backyard. I connected the ground wire directly to the chain link. I hooked it up to a Ten-Tec 555 Scout and in 5-10mins, was talking with a couple of people on 20m. With the exception of being QRP, they said they could hear me just fine. We talked for a bit. Then I jumped in on another QSO on 80m I believe.

Carl was there and he said go make the antenna horizontal. I couldn't believe it. But trusting his opinion, I did just that. I positioned the antenna horizontal went back to 20m and was able to rejoin the two people I was talking to earlier. They said I was even clearer and while still QRP they said they could barely tell! Said my signal was strong and clear!

That goes to show you that it NVIS has its value. I was surprisingly shocked that 1, it worked well as an antenna and 2, that it worked so well NVIS, horizontally!

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #11 on: August 11, 2016, 05:55:17 PM »
Note that a WOLF RIVER COIL and a short 3/8 x 24 whip can make a 3/8 x 24 version with manual tuning for people who want performance on a budget.
BUT do not expect performance on par with a dipole,just acceptable ,VERSATILE,compact antenna that is easy to use as a portable option.

http://wolfrivercoils.com/products/mini_sb.php   The MINI for 10-40 meters

http://wolfrivercoils.com/products/sb_1000.php  The Silver Bullet 1000 for 10 - 80 meters

either will work with a 4 foot to 102 inch 3/8 x 24 CB whip or even as an extended coverage /tuner for a Ham Stick or most any 3/8 inch X 24 thread antenna ...also will tune most any length attached wire instead of a whip when attached to the coil with a 3/8 x 24 bolt. Versatile .

The value of NVIS is HUGE for local communication on HF if you call LOCAL as out to 300 miles or so when HORIZONTAL oriented at as little as 4 feet above the ground though I prefer 10 or so feet for above the head of the curious clearance and MILITARY testing proved that 20 watts is optimum power for near 100 percent effective NVIS use and more power does little to improve signals above that level .
« Last Edit: August 11, 2016, 06:01:12 PM by Carl »

Offline Canadian Prepper

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Re: Portable HF antenna for emergency use
« Reply #12 on: August 12, 2016, 08:58:32 AM »
I quickly set up the MFJ mini dipole last night but couldn't listen for long. Initial results didn't look promising but a quick check to the long wire confirmed that conditions were unusually lousy.

I set her up again this morning and found that I could very easily check into two net controllers for the local 80m net, and will try some other evening net later to see how they perform. I was very impressed, since aside from some temporary fading that was probably due to conditions more than the antenna, it was easy to chat with both stations.

The mini dipole was very quite sounding on 40m (I suppose to close to a full wavelength in that band) and was just tunable on 20 (I could only get 50W out) but I'm still impressed. The dipole currently sits atop an MFJ tripod at 18 feet, which seems to make a huge difference over the 6ft high tripod I previously tried it on (difficult to hear and never really made a contact with it). If for some reason I ever have to take down my end fed W3EDP or move to another QTH where I cannot set it up, this antenna would be a viable option on 80m, and probably other bands with another hamstick combo that better tunes up on them. It also looks like a promising option for portable use when I'm in an area where there might not be enough trees to set up a longer dipole, end fed, etc.

As time permits I'll play with other options later. I'd like the idea of being able to check in on the local 40m nets with a vertical/radial NVIS setup and other options for different bands. It would probably perform equally or better to some mil-whip and other portable antenna options being marketed at over $300 on the net. I could also picture one or two of these mini dipoles being easy enough to mount on the roof of the house where a more cumbersome rig wouldn't be practical, and suspect that some great contacts might be possible with a 20m tunable set up at close to 30ft height, etc.

Far better return on this experiment than some of the used vertical options I'd seen, or other setups that would be difficult to tune or properly ground and cost at least $300 plus.

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #13 on: August 12, 2016, 10:38:35 AM »
Antenna size does effect you radio output ,and receive,to some margin...but not as much as poor placement can cause even a good antenna to perform poorly.
Remember that any antenna is just a conductor for your RF and most any metal will perform well as will a piece of PVC pipe filled with saltwater and a all thread rod to enter the 
brine conductor from the bottom...makes a very effective 10 meter vertical antenna in a pinch...lasts  for weeks and produces a great signal when used with counterpoises.

The PVC antenna that I describe needs no pump and can be configured for other bands when made longer...video of pump antenna for ideas...

https://www.youtube.com/watch?v=9tIZUhu21sQ

Offline jerseyboy

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Re: Portable HF antenna for emergency use
« Reply #14 on: August 12, 2016, 11:28:16 AM »
Antenna size does effect you radio output ,and receive,to some margin...but not as much as poor placement can cause even a good antenna to perform poorly.
Remember that any antenna is just a conductor for your RF and most any metal will perform well as will a piece of PVC pipe filled with saltwater and a all thread rod to enter the 
brine conductor from the bottom...makes a very effective 10 meter vertical antenna in a pinch...lasts  for weeks and produces a great signal when used with counterpoises.

The PVC antenna that I describe needs no pump and can be configured for other bands when made longer...video of pump antenna for ideas...

https://www.youtube.com/watch?v=9tIZUhu21sQ

Wow. It makes complete sense but I would have never thought about doing that.

Jerseyboy

Offline Canadian Prepper

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Re: Portable HF antenna for emergency use
« Reply #15 on: August 12, 2016, 03:32:04 PM »
Antenna size does effect you radio output ,and receive,to some margin...but not as much as poor placement can cause even a good antenna to perform poorly.

You raise an interesting point, namely that the ability to set up the mini dipole without it touching any trees or foiliage, passing close to other power lines, etc. might be helping a good bit, and I'll try at some point to pivot her so as to take advantage of directional gain to try to log into some nets with which I sometimes have difficulty with the end fed. Also, a really heavy downpour can throw the SWR off of the end fed on account of the proximity of wet branches and trees that rub against it, etc., so having something that might be a bit more manageable under those circumstances is desirable. More tools in the toolbox I suppose.

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #16 on: August 13, 2016, 05:41:55 AM »
This might deserve it's own thread but COUNTERPOISES or GROUND RADIALS lose effectiveness when actually on the ground and are best placed at least 2 feet above earth as
THEY ARE NOT GROUND,THEY ARE PART OF THE ANTENNA. Earth ground is POOR and lossy compared to a proper counterpoise or radial. Effectiveness of your antenna depends
a lot on your attention to such small details.

As noted before,I have found that 17 to 177 feet 6 inch long wires make effective counterpoise length for 15 to 60 meter vertical antennas like Ham Sticks and
for 6 ,10,11,12 meters ( Yes I include CB as it has proven useful) you actually use 8 foot 6 inches or FOLD your 17 foot wires back to the antenna mount so the
same 17 foot wire works all bands acceptably.

I have suggested antennas of opportunity to promote CAREFUL experimentation as you don't have to BUY an antenna to get good performance...I also use
a PAINTERS POLE made of aluminum or even a pool cleaning dip net pole that can be had for 18 feet lengths and MORE at a reasonable cost and can
SUPPORT an antenna OR BE PART OF AN ANTENNA as a vertical radiator when support trees are not available.

I use PVC as my made to order insulators though even wood or plastic items will do for temporary antennas...CHEAP IS BEAUTIFUL.
« Last Edit: August 13, 2016, 05:50:12 AM by Carl »

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #17 on: August 13, 2016, 08:11:24 AM »
To demonstrate an improvised EXTREME ANTENNA ,here is a link to military testing of LIVE TREES AS ANTENNAS for jungle communications.

http://dtic.mil/dtic/tr/fulltext/u2/742230.pdf

Offline Carl

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Re: Portable HF antenna for emergency use
« Reply #18 on: August 13, 2016, 09:38:45 AM »
Here is a PDF book of Ham pedestrian Mobile that has many ideas for portable radio operation:  Adobe Acrobat 179 pages FREE

http://w3bqc.homestead.com/WA3WSJ_s_PM_Handbook.pdf