Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Mobile HF Installation Article  (Read 1299 times)
AB1OC
Member

Posts: 10




Ignore
« on: October 13, 2014, 01:15:17 PM »

I have been working on a Mobile HF project for my F-150 truck for some time now. I've just recently completed the installation of a Scorpion SA-680 Screwdriver antenna and I'm planning to add an amplifier to the setup ion the near future. I thought that folks might be interested in the project. You can view pictures and the articles on our blog -
http://stationproject.wordpress.com/?s=Mobile+HF&submit=Search.


- Fred (AB1OC)
Logged
M6GOM
Member

Posts: 945




Ignore
« Reply #1 on: October 14, 2014, 05:54:24 AM »

Hi Fred. What an excellent set of articles and I look forward to reading Part 4. I also installed mine as much as possible to the advice on Alan's website and often get comments that they can't believe I'm mobile and I've made it through many pileups.

I have an observation and a question.

It is interesting to note that on the higher bands you noticed little difference between the Scorpion and the Hamstick. I've a Little Tarheel II I use with a 6ft whip and only really interested in 20m-10m operation. I was considering the Scorpion 680 but having to import it makes it eye-watering expensive. I may just save my money as it looks like there's little advantage.

The question is in relation to the cap hat. Have you compared the performance of the cap hat to the two whips you have? I'd be interested in observations on 20m and 40m.
Logged
AB1OC
Member

Posts: 10




Ignore
« Reply #2 on: October 14, 2014, 06:20:18 AM »

Hi Conor,

I have not had a chance to compare the cap Hat to the whips yet. One thing to note is that my HAM stick was dead center on the roof on my F-150's cab. This is the optimal mounting position of an mobile HF antenna on this type of vehicle because it puts the base the antenna right in the middle of the vehicle ground plane. It also place the base of the antenna about 3' higher than the Scorpion antenna is now. While this location worked really well, it was not very practical as my whip was constantly hitting the low tree limbs here in NH.

In terms of pure efficiency, I can tell you that the Scorpion antenna is far better and probably the most efficient antenna on the market. My new mounting position for it in the bed of the truck is much more practical and avoids  the constant contact with low tree limbs.

- Fred (AB1OC)
Logged
K0BG
Member

Posts: 9879


WWW

Ignore
« Reply #3 on: October 14, 2014, 02:35:28 PM »

Nice to see someone do it correctly the first time! Looks good Fred, and you will enjoy your efforts, perhaps more than you might realize.

Make sure you send Ron a few pix of the install for his web page.
Logged

AB1OC
Member

Posts: 10




Ignore
« Reply #4 on: October 14, 2014, 09:55:37 PM »

Thank you Alan for the kind words. I have made extensive use of you website to learn how to correctly install my mobile setup. You have done a great job making k0bg.com a tremendous resource for the Amateur Radio community.

- Fred (AB1OC)
Logged
WN2C
Member

Posts: 467




Ignore
« Reply #5 on: October 15, 2014, 12:22:35 AM »

Nice antenna Fred!  I should know, I have the 680 too and love it.  It works great.  Mine is mounted on a mount that was welded to the side of the trailer hitch mount and comes out the right rear corner of the truck.  It is set up so that if I want to take the antenna off I can take it off the mount or I can take off the entire mount antenna included.  The guy at the welding shop used a trailer hitch and sleeved the mount.  I too run the IC 7000 and they work great together.  Have fun HF mobiling! Hope to work you some time mobil to mobil, 680 to 680, 7k to 7k.

73 de Rick  WN2C

p.s. Nice pics of the install!
Logged
WV4L
Member

Posts: 141


WWW

Ignore
« Reply #6 on: October 15, 2014, 10:39:10 AM »

Greetings Fred!

Does you dash LCD display have an AUX input? If so, you could put the 7000's display up on it. It would be a lot larger and easier to read. Then you might be able to put the 7000 head, down on the center console out of the way.

73

Wayne C.
WV4L
Logged
W2RI
Member

Posts: 57




Ignore
« Reply #7 on: October 15, 2014, 10:42:20 AM »

"In terms of pure efficiency, I can tell you that the Scorpion antenna is far better and probably the most efficient antenna on the market."

Oh really?
Logged
G8YMW
Member

Posts: 237




Ignore
« Reply #8 on: October 15, 2014, 12:52:29 PM »

W2RI what would you recommend?
Logged

73 details Tony
Sent by WW2 Royal Navy signal lamp
W2RI
Member

Posts: 57




Ignore
« Reply #9 on: October 15, 2014, 01:38:57 PM »

I wouldn't be so bold as to say that my choice is "far better and probably the most efficient antenna on the market"; however, I - like many others - are big fans of HI-Q antennas.
Logged
K0BG
Member

Posts: 9879


WWW

Ignore
« Reply #10 on: October 15, 2014, 03:18:56 PM »

Here is a little experiment anyone can try. You do not want to use high power to do this, least you arc over your loading coil.

First, connect an antenna analyzer to your UNMATCHED mobile antenna with a short piece of coax—not longer than say 4 feet. Remove everything above the coil, wether that be a whip or cap hat assembly. Set the analyzer to your favorite band, whatever that is. Them move the antenna up and down to see if you can resonate the antenna to a relatively low SWR. Say under 3:1.

If you cannot, there there is very little stray and/or distributed capacitance within the coil assembly. If you can, then you have a very lossy loading coil, factory specs notwithstanding!
Logged

GOLDTR8
Member

Posts: 58




Ignore
« Reply #11 on: October 15, 2014, 07:12:54 PM »

Hy-Q are not as efficient as other screwdrivers especially the Scorpion.   Look at the 3905cc shootout results again this year Hy-Q at the bottom of the pile.   There are good  reasons for their poor performance.

Kd8nnu
Logged
AB1OC
Member

Posts: 10




Ignore
« Reply #12 on: October 16, 2014, 08:32:55 PM »

To answer the question about an AUX input on the F-150 display. The F-150's display unit does have an AUX audio input and I have the audio output of the IC-7000 transceiver connected to it. This allows me to use the truck's sound system and speakers to reproduce the radio's audio which is a tremendous improvement over the built-in speaker in the IC-7000. I have looked at the possibility of using the F-150's video display to reproduce the IC-7000's front panel but decided that a better solution was to mount the control head just to the right of the instrument cluster and on the back edge of the dash pad. This puts the radio's display and control within easy reach and the display is very readable without having to take ones eyes off the road. The crisp, color display of the IC-7000 is very readable in this location. You can find more information about this mounting arrangement on our blog here -

http://stationproject.wordpress.com/2013/08/12/mobile-hf-installation-part-14/

- Fred (AB1OC)
Logged
AB1OC
Member

Posts: 10




Ignore
« Reply #13 on: Yesterday at 05:22:40 AM »

I have been continuing to work on my mobile HF setup. I have a number of whips for my Scorpion Screwdriver antenna and I have had a chance to play with a few combinations including a 3' rod with a cap hat, a 4' rod with a cap hat and a standard 6' whip. I have done most of my contacts with the Scorpion SA-680 so far using the 3' rod/cap hat combination and it works great. I am especially surprised how well this combination works on 80m. Most of my contacts there so far have been in the USA up to about 2,000 mi. My signal reports are ranging between a 58 and a 59+10db with 100W into the antenna. I think these are good results for this power level and such a short radiator. The Cap Hat no doubt helps to improve the efficiency of the setup considerably over a standard whip. This combination looks electrically longer than a 6' whip to the antenna. I can tell this because the antenna can only be tuned as high as the 12m band with the 3' rod/Cap Hat combination (a 12m tune up requires the antenna to be fully down, minimum coil length). This combination has the advantage of a low overall height. I can resonate the antenna just fine on 10m with the 6' whip installed. Ron at Scorpion also made up a 4' rod/cap hat combination for me. I just got that installed yesterday and have only made a few contacts with it so far. I would say that there is a noticeable improvement in signal strength over the 3' rod/Cap Hat combination but I have not done enough testing yet to really gauge the difference accurately. This combination is definitely electrically longer than the 3' rod/Cap Hat combination as I can only tune the antenna as high as the 15m band with the 4' rod/Cap Hat combo. The longer rod is about the limit in terms of height given the low tree branches here in New England. I also received a 160m add-on coil from Ron and I have a new 8.5' whip that I can test as well - lots of new combinations to try. I am also most of the way through the installation of an Amplifier and Automatic antenna controller in my mobile setup. I will post more here testing results and on our blog -

http://stationproject.wordpress.com

as I complete the rest of the installation and have more time to test the final setup.

- Fred (AB1OC)
Logged
WN2C
Member

Posts: 467




Ignore
« Reply #14 on: Today at 12:38:45 AM »

I have been continuing to work on my mobile HF setup. I have a number of whips for my Scorpion Screwdriver antenna and I have had a chance to play with a few combinations including a 3' rod with a cap hat, a 4' rod with a cap hat and a standard 6' whip. I have done most of my contacts with the Scorpion SA-680 so far using the 3' rod/cap hat combination and it works great. I am especially surprised how well this combination works on 80m. Most of my contacts there so far have been in the USA up to about 2,000 mi. My signal reports are ranging between a 58 and a 59+10db with 100W into the antenna. I think these are good results for this power level and such a short radiator. The Cap Hat no doubt helps to improve the efficiency of the setup considerably over a standard whip. This combination looks electrically longer than a 6' whip to the antenna. I can tell this because the antenna can only be tuned as high as the 12m band with the 3' rod/Cap Hat combination (a 12m tune up requires the antenna to be fully down, minimum coil length). This combination has the advantage of a low overall height. I can resonate the antenna just fine on 10m with the 6' whip installed. Ron at Scorpion also made up a 4' rod/cap hat combination for me. I just got that installed yesterday and have only made a few contacts with it so far. I would say that there is a noticeable improvement in signal strength over the 3' rod/Cap Hat combination but I have not done enough testing yet to really gauge the difference accurately. This combination is definitely electrically longer than the 3' rod/Cap Hat combination as I can only tune the antenna as high as the 15m band with the 4' rod/Cap Hat combo. The longer rod is about the limit in terms of height given the low tree branches here in New England. I also received a 160m add-on coil from Ron and I have a new 8.5' whip that I can test as well - lots of new combinations to try. I am also most of the way through the installation of an Amplifier and Automatic antenna controller in my mobile setup. I will post more here testing results and on our blog -

http://stationproject.wordpress.com

as I complete the rest of the installation and have more time to test the final setup.

- Fred (AB1OC)

You know Fred, I have often wondered what would happen if you took an alligator clip with a length of wire say about 40 or 50 ft and put the end up in a tree and clip the other end to the Scorpion. Maybe throw out some radials.  I might try this when I get up into the mountains of Az.

Rick  WN2C
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!