ht w/rubber duck Tx distance/ wattage estimate

[EFUDD]

Okay y'all, here is what I've got as far as a question. First off I bought a Yaesu vx7r for my first radio. I live about 15 north of Charlotte nc and have been able to check in on some nightly nets in the foothills (lenoir and wilkesboro) using my ht and the rubber duck that came with it. I've checked google maps and the best estimate for mileage as the crow flys would be right at 50 miles for both of these repeaters. Is there a way to estimate how far a 5 watt ht should transmit? I'm also wondering if my radio may have been altered by the previous owner.  Is it possible that my ht may actually be tx'ing @ 7-10 watts? I haven't connected with anyone that has tester yet and I may just grab one at the Charlotte hamfest next month.  I just wanted to see what estimates and insight y'all may be able to provide.

Thanks,
Lee
Kk4gev

[WB6BYU]

Coverage distance is greatly dependent on terrain, much more so than power.

I can talk through a repeater 100 miles away on my HT, and it only runs 2 watts output.
And another one 70 to 80 miles.  But both of those are on hills (4000 to 7000 feet) and
are nearly line-of-sight for me.

If your radio really is putting out 7 to 10 watts, it will get too hot to hold pretty quickly.
(But it may do that at normal high power anyway.)

[WX7G]

There are no mods I know of to increase the TX power of your HT.

[KD8HYN]

My first radio was/is an Icom-V82, with its stock rubber duck I could barely hit the local repeater in the same neighborhood, but with the huge and unwieldy Diamond RH205, I could key it at .5 watts from 30 miles away. I had a very clear QSO with that antenna across town, 20 or so miles the other day at 7 watts with that antenna on my car's mag mount (stationary).

You really can get pretty far with an HT, I dunno about Yaseu but Icom's stock antenna was just junk.

[EFUDD]

There are no mods I know of to increase the TX power of your HT.

That is actually a little bit of relief!  I was starting to worry about releasing the "magic smoke" from my radio pre-maturely.  So I guess it's fairly common to be able to hit repeater at that distance then.  I'm going to start trying to reach out in other directions to just see what "she'll" do with her rubber duck antenna. Maybe if I work some repeaters toward the sandhills or the coast, I'll have a further reach.

Thanks for the info y'all!

[KATEKEBO]

On VHF / UHF it's the location that counts because for most of the time, VHF / UHF is line-of-sight communication.  You can talk hundreds of miles with 5W, as long as the antennas can "see" each other.  From personal experience I have made 80 miles simplex QSO's and hit repeaters over 130 miles away using an HT with a rubber duck antenna - operating from the Clingmans Dome in the Smoky Mountains.  The higher you get, the farther you can talk.

[N6AJR]

a couple of options, you can get an outside antenna and run a coax into the house and the outside antenna up a bit, for better coverage  and also there is a MFJ-310 which hooks on your car window and puts your rubber duck up above the roof line, under 20 bucks.

[KB3HG]

Suggest looking for reviews on the radio. Rubber ducks are generally referred to dummy loads, an external antenna will yield better results. Distance varies with terrain and obstructions. sometimes my Ht can make repeaters 10 to 12 miles out and sometimes not 5 miles for me, mild hills holes in elevation and Iron Ore (low grade)  in the ground around here. to give you an idea where I am look at a map for where MD, PA and DE state lines meet, that's where I am. Delaware City  70 cm repeater has about the best coverage for about 1/2 the state. Not a big state.  Remember the higher the antenna the better the range.

Tom Kb3hg

[KB4QAA]

The cheapest, easiest improvement you can make is to add a 19 inch counterpoise.  Take a peice of wire, strip off a couple inches and wrap it around the base of the antenna connector.  Cut is to about 19-20 inches.   You will be amazed at the improevement.

After that an extendable whip is an improvement.  I usually carry both a rubber duck and a whip antenna in my pocket when I am out in the hinterlands afoot.

Make a 3 element yagi.   An even simpler project is "The Repeater Eater" 2 element quad, which you can find in the QST archive from the early '90's.

bill

[G8JNJ]

HI,

You may wish to take a look at the free Radio Mobile radio coverage software produced by Roger Coudé, VE2DBE

Some excellent notes to get you started can be found here:-

http://www.g3tvu.co.uk/Radio_Mobile.htm

This sort of software has been used by industry for many years to predict the coverage area of fixed and mobile radio communication stations. However these commercial packages cost tens of thousand dollars. Radio Mobile provides a very good level of accuracy for free.

I've used it to check new QTH's before moving house on several occasions 

Regards,

Martin - G8JNJ

www.g8jnj.webs.com

 

[K6LCS]

Many a time, an antenna improvement on an HT is worth more than doubling/tripling your output power.

I mean, I regularly work stations that are more than 500 miles away from me all the time - with an HT and a little better antenna. No problem working those FM LEO satellites with a 1-Watt or so HT!

But put me in a downtown basement, and that same signal might not travel more than a few feet.

"Line of sight" is our guiding principle for FM voice comms on 2M/220/440. If your antenna has a straight shot - and can "see" the other antenna you want to work - you'll probably work it. Big Bear mountain is about 40 miles away from me - no problem with the stock duck hitting that "straight shot." Santiago Peak is 25+ miles from me - but also a "straight shot" and can be worked with 'bout any HT and their stock antennas.

SO - how far will 5W go on your radio? Anywhere from 25 feet to 500 miles, in my experience.

Clint K6LCS
909-241-7666 - cell

[EFUDD]

The cheapest, easiest improvement you can make is to add a 19 inch counterpoise.  Take a peice of wire, strip off a couple inches and wrap it around the base of the antenna connector.  Cut is to about 19-20 inches.   You will be amazed at the improevement.

After that an extendable whip is an improvement.  I usually carry both a rubber duck and a whip antenna in my pocket when I am out in the hinterlands afoot.

Make a 3 element yagi.   An even simpler project is "The Repeater Eater" 2 element quad, which you can find in the QST archive from the early '90's.

bill

I'm a little leery of that 1st option.....I've added wire to improve reception for Broadcast FM but thought it just wouldn't work for transmitting.  exactly how does this work?  Wrap it around the threaded portion of the connector?   I'm extremely cautious with anything I do with the radio now since I wouldn't be able to replace it if a part broke or the "magic smoke" leaked out.  I have been trying to find the QST article and have found where it was listed, but couldn't access it.  Thanks for the info, I just like the name "Repeater Eater"!!!
Lee

[EFUDD]

Many a time, an antenna improvement on an HT is worth more than doubling/tripling your output power.

I mean, I regularly work stations that are more than 500 miles away from me all the time - with an HT and a little better antenna. No problem working those FM LEO satellites with a 1-Watt or so HT!

But put me in a downtown basement, and that same signal might not travel more than a few feet.

"Line of sight" is our guiding principle for FM voice comms on 2M/220/440. If your antenna has a straight shot - and can "see" the other antenna you want to work - you'll probably work it. Big Bear mountain is about 40 miles away from me - no problem with the stock duck hitting that "straight shot." Santiago Peak is 25+ miles from me - but also a "straight shot" and can be worked with 'bout any HT and their stock antennas.

SO - how far will 5W go on your radio? Anywhere from 25 feet to 500 miles, in my experience.

Clint K6LCS
909-241-7666 - cell

LOL! so close enough to whisper to a friend, up to a long distance phone call!  I have experienced the dreaded "in the Truck" syndrome.  Been using a repeater 30 miles away, then get in the vehicle and I can't hardly turn the repeater on!  But all that will work out when I get a mobile/mag mount from a buddy of mine.  Where I live in NC we have some rolling hills and some flat land too, all rolled into one happy little package.  We are also located in the South central part of the state.  I haven't tried to access the repeaters toward the coast, but have hit some in the foothill region (about 50 air miles).  I have been able to turn on a few repeaters in the high country (Boone NC) but don't know what amount of voice actually made it (no one responded, and I haven't found a net on one of those "distant" repeaters to test the voice yet).
Thanks for the input!
73'S
Lee
KK4GEV

[EFUDD]

On VHF / UHF it's the location that counts because for most of the time, VHF / UHF is line-of-sight communication.  You can talk hundreds of miles with 5W, as long as the antennas can "see" each other.  From personal experience I have made 80 miles simplex QSO's and hit repeaters over 130 miles away using an HT with a rubber duck antenna - operating from the Clingmans Dome in the Smoky Mountains.  The higher you get, the farther you can talk.

You just gave me a reason to head to the Smokies!!!! Now how can I disguise it so it's an acceptable trip to the wife?  Flyfishing and Ham operations are two good ones for me, but I don't know if she'll go for it......maybe I can drop her off on the other side of the mountain in Pigeon Forge and them come back to Clingman's Dome!
Lee
KK4GEV

[WB6BYU]

The cheapest, easiest improvement you can make is to add a 19 inch counterpoise.  Take a peice of wire, strip off a couple inches and wrap it around the base of the antenna connector.  Cut is to about 19-20 inches.   You will be amazed at the improevement.

I'm a little leery of that 1st option.....I've added wire to improve reception for Broadcast FM but thought it just wouldn't work for transmitting.  exactly how does this work?  Wrap it around the threaded portion of the connector?

I've actually measured this - over a range of antennas the average increase was 9dB: that
is like running 8 times the output power.  It might not be quite the same on every radio, but
it still can make a significant improvement.

My HT has one of the older BNC connectors for the antenna.  I take about 24" or so of light
stranded, insulated wire, strip the insulation off one end.  Take the antenna off the radio,
wrap the wire around the ground side of the antenna jack and twist it together, then stick
the antenna back on to hold it in place.  Trim the hanging length to about 19".  One approach
is to tune in a distant repeater that is weak and noisy, then add the wire and see how much
difference it makes.  You can even trim the wire length for best reception as long as you have
a signal that isn't full scale on the radio.  You can also solder the wire to a lug that fits under
the antenna connection.  On a newer radio with an SMA connector you can wrap it around the
connector shell, or secure it to a screw somewhere on the radio that make contact with the
case.

The whip on an HT is a vertical antenna - half of a dipole.  Ideally it works a against a ground
plane or a radial system:  the HT case normally suffices, but it is smaller than optimum (especially
as radios get smaller.)  The wire works as a quarter wave radial and turns your monopole into
a dipole.  Using a longer antenna on the HT also helps - a quarter wave whip made from brazing
rod might be a starting point.


There are lots of types of antennas that you can add to your radio, many of which you can
build at home for little cost.  The most important improvement you can make is height.
If you can't get up to Clingman's Dome whenever you want to work a particular station then
putting an external antenna up on the roof, or on a mast, is the next best thing.  A simple
ground plane antenna built on a coax connector works about as many of the other antennas.

For more gain you can build yagi or quad beams, quagis, etc.  I have several that fold up so
I can carry in my hand luggage on international flights.  For backpacking or portable work,
weight and size may be important factors, but for home use that isn't as much of a limitation.
Choosing one is mostly about choosing a construction method that is within your abilities
and resources, and thinking about how you will use it and therefore what physical factors
are important.  I have trouble drilling a straight hole through a piece of PVC pipe, and I've
built lots of simple beams that work very well.

Here are some links that show you various sorts of home-brew antennas you can build -
any of them will work, regardless of whether it has a fancy name or not.  But remember
that height is more important than gain - first get you antenna up higher in the air, then
think about improving it.

http://www.wa5vjb.com/yagi-pdf/cheapyagi.pdf
http://commfaculty.fullerton.edu/woverbeck/quagi.htm
http://www.cebik.com/content/a10/vhf/fmant.html
http://www.mydarc.de/dk7zb/
http://www.k7mem.150m.com/Electronic_Notebook/antennas/yagi_vhf.html
http://www.ifwtech.co.uk/g3sek/diy-yagi/index.htm
http://www.yu7ef.com/LowTemperatureAnt.htm
http://www.geocities.jp/jk7tke502/antennas_album_eng.html
http://www.cebik.com/content/a10/quad/2mq.html
http://www.cebik.com/content/a10/vhf/2mowa1.html
http://www.cebik.com/content/a10/vhf/scales.html
http://www.cebik.com/content/ao/ao1.html
http://www.cebik.com/content/ao/ao2.html
http://www.cebik.com/content/ao/ao3.html

The links to cebik.com are the website of the late W4RNL, and require a free registration.  It is
well worth it, as it is a wealth of antenna information and you can spend weeks reading through
everything (though not always strong on practical details, except the last couple articles.)