[SMCARA] To Spice or not to Splice

[Clarke, Tom AIR4.0P NATOPS]

Hi Bill,

Not sure what you want to do.  Are you talking about a random/long wire, or a resonant type (dipole, loop, delta, vert) antenna?  Or is the question just about the mechanical aspects, i.e., splicing the wire?

For a splice, use a Western Union or Lineman's Splice (https://www.google.com/?gws_rd=ssl#q=lineman%27s+splice) for the mechanical joint and then solder it.  Clean the wire well before splicing using a knife to scrape and sandpaper.

If you have an antenna that is resonant at the wrong point, adding wire to lower the frequency is a valid approach and will make the antenna more efficient (i.e.,  lower the loss due to VSWR effects on the coax feedline) resulting in more RF going out into the ether!

If you are talking about a random wire or a beverage type antenna, more is generally better. Capture area rule makes this so.  

A lot of antenna theory seems related to "black magic" sometimes, but there are some hard and fast rules (supported by some eye watering math!) that must be observed. Basically, you can't fool Mother Nature!

L. B. Cebik, W4RNL (SK) has written extensively on antennas and may be found all over the internet.  W8JI, K0BG have also written on the subject.  Jerry Sevick, W2FMI (SK) also.  A Google search will bring you tons of articles.

I heard an interesting discussion on a local repeater recently concerning radials for a vertical antenna.  The FCC favors a minimum of 120 radials around a 1/4 lambda (90 degrees) in length.  That's a lot of wire folks!

Conventional wisdom speaks to 30 or more 1/4 wave radials for ground mount and minimum of 4 (per band)elevated and tuned radials, although some will consider 60 a minimum number.   I had a Hustler 4BTV mounted on a terra cotta roof with 4 stub tuned elevated radials and it worked great.  I am sure having the EA7BXP call sign added a few dBs!  My current vertical has 32+ radials about 25 feet long and it works well. I will probably add a few more radials this year.  They started out laying on the ground held in place with garden staples, but now are covered with mulch, leaves, and assorted vegetation. Keep in mind that ground mounting the radials detunes them so don't get hung up on precise measurements!  Some longer, some shorter; they all help.

I haven't made any field strength measurements, but the antenna loads up well ( no tuner ) and makes QSOs.  I tried this antenna once without radials and it showed a nice VSWR, but didn't get out worth a flip!  A 50 ohm dummy load will show a low VSWR also!
 Just sayin"!!

Keep the RF flowing!

73 Tom/W4OKW

Clarke's First Rule of antennas:  "If it sounds like a stupid idea, but it works, it's not stupid"!

-----Original Message-----
From: SMCARA [mailto:smcara-bounces at mailman.qth.net] On Behalf Of Bill Jones
Sent: Thursday, March 26, 2015 8:50 AM
To: smcara at mailman.qth.net
Subject: [SMCARA] To Spice or not to Splice

Can you without without any loss extend a wired antenna? Or do you just rerun new wire? And if so, do you just tape it and then liquid tape it to maintain integrity? Thanks!

Bill

--
KC3DEZ
www.qrz.com
______________________________________________________________
SMCARA mailing list
Home: http://mailman.qth.net/mailman/listinfo/smcara
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:SMCARA at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message delivered to frederic.clarke at navy.mil