Survivalism & Self Sufficiency Topics > Amateur Radio Gear Reviews

N9TAX Slim Jims in VHF/UHF

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Canadian Prepper:
Hopefully I'll get enough of an opportunity to practice so as to be able to provide a worthwhile review soon, but I just got two N9TAX Slim Jim antennas with 16 feet of coax in VHF and UHF. I got one with the PL239 connector and another with the SMA female used on Baofeng HTs along with an adapter from SMA female to PL239.

At least one of these antennas will be packed away into my HT go bag and the other is currently being used in my QTH on my FT-897D for when I want to operate on 2m/70cm. The Workman UVS200 antenna that I've got for those two bands is currently exhibiting high SWR and will have to wait until a friend comes by with his SWR meter to figure out and hopefully fix, but given that I'd want a Slim Jim for portable use I'm going to try it on all of the local nets and repeaters in the upcoming weeks.

So far I've had a nice QSO with someone off of our main repeater and checked into an net on another one shortly afterwards. I was only using 5W and had hung the antenna right outside of a doorway with lots of metal siding nearby, but will try t get it into a better position soon. It will also be interesting to see how far I can get with the Baofengs attached to one of these. They are surprisingly compact when rolled up and can easily fit into even a small go kit.

At under $30 each and with stateside shipping, these products seem to offer a great deal of capabilities for less than the cost of a single UV5R. I'm keeping my fingers crossed that I'll find the time to test and review them more thoroughly in the coming weeks.

Ken325:
I did the same thing you did about a month ago. I bought one N9TAX slimJim, and I hung the antenna in the attic above my 2nd floor (3 stories high). I then ran 30 feet of LMR 400 coax to my office.  I hung it vertically about 7 feet from anything metal using zip ties and paracord.  I am in a HOA so no external antennas.  I can hit repeaters at least 20 miles away but I haven't tried further than that yet.  I had good results listening with this antenna using my baofeng UV5R and an adapter.  Much better than the rubber duck.  Then I passed my technician license about 2 weeks ago.  I would give my new call sign but it appears that you can look up my address if I do that, so my call sign will not be associated with my prepping unless I really trust someone.   I bought a Kenwood TMD710GA after passing the test.  It was $140 off because of the Dayton ham show.  That is an expensive radio for a first real radio, but I like the detachable face plate and  I am interested in using digital modes.  With the discount it was close enough to the TM-71A to justify the cost increase.  I have been listening to Fo-time, and the Partisan Radio podcast on pod bean.  It is associated with AMMRON  and it is hard core prepper communications that is very focused on how to do things.  Stuff like setting up a burner phone, encryption, encoding and decoding messages.  Good stuff and I highly recommend it you are not listening already.  Anyway I am very new to ham and I am trying to figure out stuff.  Is there a way to listen to a repeater that is out of range (45 miles)?  I know I can hit a repeater and push my signal out further but can I listen further?  I need to figure out stuff like echo link.  Anyway, I started putting a comm's box together for all my radio gear that I would want to take on a bug out.  I bought a second N9TAX slim jim with the 16 foot coax for my com's box. Gurilliacom on youtube did a great review of this antenna https://www.youtube.com/watch?v=gk9kgi__cE0.

I do have a question for more experienced hams.  I have an engineer friend who says I have to have a ground on both ends of the coax or the coax will act like a antenna and it will mess up performance.  The antenna is in a difficult place in my attic and I see no way to put in a ground other than punch through the outer wall in the attic and run a ground down 3 floors.  The ground would be at least 50 feet long and the HOA may complain if I do this.  I was told on this forum under a thread on antenna problems that this antenna does not require additional grounding.  It seems to be working well.  The highest SWR has been 1.6 and the performance is about what I expected.  Any opinions on the need for a ground and do I need to do something on both ends of the coax?  Also, I put a 1/2" ferriet bead on the coax about 4 feet below the antenna. No reason that I thought this was required, but it is dam hard to get into the attic in this location, so I thought I would take preventive steps just in case.  It sounds like the ferriet is not harmful just stops RF interference from traveling on the outside of the coax.  Opinions wanted if you have one. 

FreeLancer:
I like mine, all three of them.

SCWolverine:
I used the N9TAX as my primary base antenna for almost a year when i first got in.  It combined with my Wouxun HT (the cheap HT of it's time at $120) worked very well.

I too have the 16' coax version, and mine is terminated with a BNC.  Actually, I use BNC for most everything that I buy manufactured.  It's easy and convenient.

The design of the N9TAX and Ed Fong Jpoles (all J Poles I believe) do not require a ground due to it's design.

Thanks for listening to Fo Time, and I concur that JJS is doing a nice job on his Partisan Radio Show.

You can change your address to a PO Box if you are interested.  Everyone knows me, but I'd encourage you not to share your call anywhere online that you don't feel comfortable.  The change of address can be handled on the FCC site, and the POB offers you some insulating anonymity for very little cost.

SCW


edit to add:

to listen further you may have to go to a directional sort of antenna.  There are some low cost yagis that could be installed in an attic space, and even mounted to a rotator therein.  The yagi design would allow more 'gain' and may increase your signal reception and transmission (vs. your J-pole)

ex: http://www.cheapham.com/htek-dual-band-2m-70cm-yagi/

your J-pole is an omni directional antenna (receives on all sides) whereas a yagi or other directional antenna receives best from the direction it's 'pointing at'.  to add a different antenna, you'd also need an additional run of coax and maybe coax switch in the shack.

you can also hombrew a yagi if you are interested!

Carl:

--- Quote from: Ken325 on June 03, 2015, 10:34:58 PM --- Is there a way to listen to a repeater that is out of range (45 miles)? 

 I have an engineer friend who says I have to have a ground on both ends of the coax or the coax will act like a antenna and it will mess up performance. 

--- End quote ---

Is there a way to listen to a repeater that is out of range (45 miles)?   

If you could do this ...it would not be out of range.  ::) VHF and UHF are LINE OF SIGHT radio...
basically you must be able to 'see' the receiver antenna...
DIRT is a bad conductor of radio signal and the curvature of the earth,Hills,mountains all will BLOCK your radio signal
when they get between you and the receive antenna.The earth is not flat and for two guys on foot and "flat" ground,
the limit that you can talk with VHF/UHF is about 5 to 7 miles and higher power does little to help as dirt is good at
getting in the way.(So being mobile is not so much better than hand held except for a bit of antenna efficiency.
 To talk farther,the antenna on one or both ends need to be higher to see farther ...How high??

Using the line of sight calculator we see NOTE that when you include a repeater in the middile,the height of the repeater is the limiting factor...though you will not use repeaters much in SECRET as most repeaters cost big money and club membership helps pay that cost.
You will also find the value of community with clubs/repeaters  and being know to others as you won't get far with no one at the other end.

BOTH antennas at 6 feet give a range (due to curvature of earth)            of 6 miles
One at 6 feet and one at 30 feet (typical base to hand held or mobile)        11 miles
Repeaters are placed in high spots for a reason (a 200 foot tall repeater)   23 miles
The tallest repeater in my area is at 1000 feet (up on a TV station tower)   48 Miles

At longer range (15 mile plus) path loss will begin to also limit how far you can talk so at that point power will help,though not
as much as you may think..IE TEN TIMES the power will NOT double the range ...though when 'they ' have noisy signal the
power increase will help clear up you readability .

VHF and UHF are used for LOCAL communications for a reason as ,on earth base stations, they are limited.
As co-holder (it takes two) of the world record over land VHF record ,( NW Louisiana to central Maine) I know a bit about getting VHF to work ,though a lot of LUCK was involved.


Line of sight calculator:  http://www.qsl.net/kd4sai/distance.html


Your second ? of a GROUND  , NO it is not helpful or even beneficial for your antenna.Though the ferrite bead IS a good thing for the reasons you gave with RF interference.


And reading ahead I see SCW suggest a YAGI and while this helps ,you need height above ground with the yagi to get best results and a rotator as the YAGI received in one direction best (though ,one direction may be all you want)

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