[Mobile-Portable] Screwdrivers and whips

N5WV n5wv at comcast.net
Sat Jan 18 18:32:24 EST 2014 

Hello Group , I had only used Hustler HF antennas while mobile and had good results. Then went to a Scorpion SA 680 and had better results. Last summer I purchased the American Red Cross Ford Excursion ECRV 4707 from the Houston chapter. Most equipment was left intact . It has a SGC HF tuner and whip system installed. The whip is about 102 " and perfect for 10 meters. It does great on 10 to 15 but slacks off compared to the Scorpion. But its easier to install. I had a $500.00 L mount fabricated to mount the big heavy Scorpion on. Had it done first class , powder coated , etc. There is just so much more receiving with a Scorpion type antenna so it does better on the lower bands. For instance , I mainly listen. When I first bought the Scorpion I purchased a Radio Shack 102 " whip for it. About a month later I got back home from a trip and the whip was gone. The whip had broken off just above its lug where it screws into the top of the screwdriver antenna and I had not hit anything at all. After I removed the broken piece and after closer inspection the metal had small bubbles in it from a bad mix or temp problem. I found one of the old Antenna Specialist 108 " land mobile whips to replace it with. The RS whip broke off at some point while I listened to 20 meters the entire trip. I know it was on when I left because I always look at it. But throughout the entire trip listening to 20 meters , I still had great signals and did not notice any change in signal strength. Im sure there was some signal strength loss . I even have a 7 " LCD tv atop my dash showing the IC 7000's display. But there was no drastic loss of signal. The SA 680's coil and tubing was still receiving a good signal with no whip atop it. To add a bit more insurance I added a Antenna Specialist spring between the SA 680 and 108 " whip. This takes the pressure of the lug somewhat and moves it to the springs connecting part. So the bigger the antenna , the better it receives. Have a nice weekend , Great group here. Randy N5WV 

----- Original Message -----
From: "K0DAN" <k0dan at comcast.net> 
To: "Mobile-Portable Reflector" <mobile-portable at mailman.qth.net> 
Cc: iam at pmug.org 
Sent: Saturday, January 18, 2014 11:01:04 AM 
Subject: Re: [Mobile-Portable] Screwdrivers and whips 

I did the same thing (whip + tuner). Had a lot of fun (mostly higher than 14 
Mhz) and made a lot of contacts. But missed out on a lot also (mostly lower 
than 14 Mhz). 

I am no longer mobile on HF but if I were to do it again I would definitely 
come up with a screwdriver design, and follow the guidelines on the K0BG 
site http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=12686 

Have fun. 

73 
dan 
k0dan 

-----Original Message----- 
From: David 
Sent: January 18, 2014 00:17 
To: Mobile-Portable Reflector 
Subject: Re: [Mobile-Portable] Screwdrivers and whips 

You are right! 

I wasn't wise. I should have done my antenna efficiency studies BEFORE I 
spent all that time and energy on the whip & tuner installation. BUT, 
going back to the screwdriver cured the problems. 

David 
W7DBH 



** The K0BG site is like a Handbook for HF mobile operations. Whether or not 
** you believe an efficient HF mobile station can be built on-the-cheap, you 
** are sure to find some good tips and practical info of various 
** installations here. 
** 
** My own experience is that the ~108" whip with auto tuner is relatively 
** stealthy (as stealthy as a 108" whip can be), but , even when installed 
** high 
** up, has poor radiation efficiency on freq's below about 14 Mhz. The tuner 
** will make the transmitter happy but a lot of energy is being lost into 
the 
** ground and vehicle chassis, and not going into the ether where it 
belongs. 
** 
** Of course you can make contacts at 40M and 80M (even 160?!?) with a whip, 
** but the reality is a tuned antenna with an excellent vehicle ground 
** distribution (and no noise) will give you 3-6 dB or more radiation 
** efficiency. 
** 
** As with all things, your mileage may vary. 
** 
** http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=12686 
** 
** 73 
** de k0dan 
** 
** ______________________________________________________________ 
** Mobile-Portable mailing list 
** Home: http://mailman.qth.net/mailman/listinfo/mobile-portable 
** Help: http://mailman.qth.net/mmfaq.htm 
** Post: mailto:Mobile-Portable at mailman.qth.net 
** 
** This list hosted by: http://www.qsl.net 
** Please help support this email list: http://www.qsl.net/donate.html 
** 
** 


-- 
David B. 

______________________________________________________________ 
Mobile-Portable mailing list 
Home: http://mailman.qth.net/mailman/listinfo/mobile-portable 
Help: http://mailman.qth.net/mmfaq.htm 
Post: mailto:Mobile-Portable at mailman.qth.net 

This list hosted by: http://www.qsl.net 
Please help support this email list: http://www.qsl.net/donate.html 

______________________________________________________________ 
Mobile-Portable mailing list 
Home: http://mailman.qth.net/mailman/listinfo/mobile-portable 
Help: http://mailman.qth.net/mmfaq.htm 
Post: mailto:Mobile-Portable at mailman.qth.net 

This list hosted by: http://www.qsl.net 
Please help support this email list: http://www.qsl.net/donate.html

More information about the Mobile-Portable mailing list