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Old 22-08-2011, 13:10   #31
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Sure, why not? Wire is wire. The diameter might make a bit of a difference for tuning, but not enough to really notice. I'm using left over speaker wire and put out a better signal that most land stations.

I'll eventually replace it, but it's way down on the list right now.
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Old 23-08-2011, 12:58   #32
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Re: Ham on a Budget

Quote:
Originally Posted by drew23 View Post
thanks all for such thoughtful replies!

yes, btw, I am a licensed ham - VA7DSX, hopefully soon to be VE0TF. I am jumping though as many bureaucratic hoops as are being thrown at me currently, and intend to have all of the appropriate station licenses to operate internationally.

much to think about! so far I'm gathering that spending the extra couple of hundred on an SGC tuner is not money wasted...?
Drew,
Well it's good that you're a ham....and that you're looking into getting things set-up correctly.....
Congrats on both of those!!!!


I'm not going to argue over a db......but, I just might be able to help......


Perhaps I could make a comment / add some advice, that will put me way out on a limb????
The number one, most important quality for an effective and efficient HF system is operator skill / knowledgo / experience.....

This in NO way is meant to imply that anyone here isn't skilled / experienced....
But just that while everyone seems concerned over what to use for a radio (my opinion: spend the $$$ on an M-802 and you'll be happy), what to use for an antenna (Bill's alternate backstay would be my recommendation as well), what to use for a counterpoise (you guys really need to buy your copper strapping somewhere else, see below for details....), etc.....the skill, experience and ability to operate the system
effectively hasn't been mentioned...

I'm not one of those arrogant blow hards that thinks since I needed to learn morse code ~ 40 years ago, draw / troubleshoot written schematics, etc. (I did) in order to get a license that everyone nowadays should do the same....that's NOT what I'm trying to impart.....

Rather, I'm trying to impress upon everyone (new or old to HF radio, etc.) that an experienced, skilled operator can take a mediocre radio, a simple antenna, with a questionable installation, and make many contacts on various bands, night or day, over great distances......BUT, the opposite is NOT the case.....
An inexperienced or poorly trained operator can be given a top-of-line, perfectly working radio, properly installed and still have difficulties making contacts......


So, wanting a "ham set-up on the cheap" is very do-able using the advice givern here, by many:
a) Using a marine HF transceiver (either an older marine transceiver, or a more modern one, such as M-802, M-710, or other high quality unit)....
b) Rigging an alternative backstay antenna, fed with a remote tuner (SGC or Icom)....
c) And a simple counterpoise / ground system (copper strap to a thru-hull, or toerails / lifelines, or radial wires, etc.)

BUT, one of the cheapest things to do to accomplish your goal is to spend the time and effort (no $$$$ needed!) to gain the knowledge, skill, and experience to make even a "cheap" set-up play well!!!!
Now, I realize that it isn't as quick and easy as I make it sound here.....as I've been doing this close to 40 years now.....but, there have been others here in the past that have mentioned how much money/time/effort cruisers spend on many, many other items/systems, but seem to ignore learning the ropes of HF radio operations.....

So, here's the best advice I can give......
Buy and read the ARRL Radio Amateurs Handbook......
www.arrl.org
(and perhaps Marti Brown's book, "Marine SSB for Id-i-Yachts")
And then spend a lot of time listening on-the-air, even if there's nothing much to listen to.....


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Just a few basic examples.....
a) Learning the basics of radio propagation, learning what atmospheric noise is and sounds like, why the sun does a lot more than just charge the ionosphere, etc.....all allows you to know what band/freq to use at what time of day, for a specific communications path, etc..

b) Just learning the very basic correct/proper radio terminology, and knowing the phonetic alphabet, etc. will allow you to pass info, and get accurate reports, etc. when others are asking "huh???"
(heck, just learning to say "Roger" is a step up for most on-the-air thesedays!!!)

c) Understanding that the best way to communicate is to listen more than you talk......(something "motor-mouths" like me still need to remind ourselves of!!!)

d) Knowing what "RF" is.....

e) Knowing what different noises are, and where they may be coming from.....
Some are "natural", lightning crashes, geomagnetic storms, etc....
Some are "man-made", electrical noise from inverters, battery chargers, refrigeration units, fans, meters, etc....
Some are nearby (on your boat of very close) and some are miles away.....etc.....
Some are "spurious noise" from others.....and some of these "spurious" signals can also be coming from your own radio.....
Some are other transmissions......(a personal example here was an ALE "sounding" transmission a couple years ago, blanking out some maritime HF channels, was a gov't system that had been incorrectly programmed.....it took a few weeks for the "gov't" to figure out which one of the systems was doing it, and when I pressed, I was told "we can't say"....)

And, then there are the noises that you, yourself are transmitting....
And, that can be everything from a 12 volt fan blowing on you, keeping you cool but also causing others to have trouble understanding what you are saying.......
Or, all the way to having your radio misadjusted, and distorting your own signal.....(seeing a meter deflect farther, does NOT mean others can hear you better!!!!)...another reason to use a commercial marine HFtransceiver where you won't be able to screw things up (at least not much...)

Heck, I could on and on about noises, etc.....but you get the point....


Please understand that the smartest people I've ever met are the ones who asked a lot of questions, read a lot of books, and were never concerned about "looking stupid".......they are always learning!!!!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For some additional info/thoughts/data, have a look at these pages....


Here are many thoughts on marine radios, particularly the Icom M-802....
SSCA Discussion Board • View topic - ICOM 802 - Purchasing a New SSB Radio


And, here are many thoughts on the KISS-Ground....
The KISS SSB Counterpoise - Revealed ( with Pics )


And, here's where you can buy clean, smooth, thick copper strapping CHEAP.....the stuff I recommend for most is 0.012" thick and will not "waste away" in a few years.....
GEORGIA COPPER - Copper ground strap
This stuff is 4 times thicker than the crap you're being sold by "marine stores", etc.....and is much, much cheaper.....
Cost for your average boat is going to be less than a nice dinner...
(heck, I've even bought copper strapping on sale for less than $10 for a 25' roll of 0.012" thick strapping....)


(I use the 6" wide 0.022" thick and 3" wide / 0.022" thick strapping... GEORGIA COPPER - Copper ground strap and, I spray them with some clear laquer where desired.....but, I'm a fanatic!!! )

Here's a few photos of my Nav Station.....
Nav Station

and of my 5+ year old copper strapping attching to my 2 large Dynaplates, and of my pricey Hydn Hi-Mod backstay insulators (with the Sunbrela cover removed), and
4705407
4706601
4711201
4705408


and a few shots of my shack at home...
QRZ.COM Callsign KA4WJA



Not sure if anything I wrote here will be of great help.....but I tried....

John, KA4WJA
s/v Annie Laurie, WDB6927
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Old 23-08-2011, 13:13   #33
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Re: Ham on a Budget

Drew,
I forgot one simple thing....

A good pair of headphones!!!
Until you really experience the difference a good pair of headphones can make when listening to signals that near the noise level, I cannot explain here in words.....

Do not waste the $$$ on "noise cancelling" headphones, nor DSP speakers.....
Look for a pair of decent communications headphones, or even an inexpensive pair of music headphones......(no need to spend more than $50...)
Do NOT try to use computer earpices nor ear buds, etc.....they're a waste of effort....

I personally like Kenwoods, but have a pair of cheap ($25 - $30) MFJ headphones on my boat that work great, and I don't care if I ruin them!!!
(and, I've evn got an old pair of "on ear" headphones from Radio Shack (< $20) that work pretty well....)


Bottom line:
Gaining the knowledge and skill, along with a good pair of headphones will do more than you can ever imagine for your "Ham on a Budget" set-up....


Fair winds.....

John, KA4WJA
s/v Annie Laurie, WDB6927
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Old 23-08-2011, 13:26   #34
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Re: Ham on a Budget

Wherever you get the headphones, make sure they surround your ear and block out the outside noises (a boat underway can be very noisy, and having crew talking while you're trying to hear a weak signal is very frustrating.) The foam "on-the-ear" headsets just don't block the ambient sounds very well.
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Old 23-08-2011, 13:42   #35
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Re: Ham on a Budget

Quote:
Originally Posted by fairbank56 View Post
A db is a db. A 3db change in voltage is a 3db change in power.Eric
I very hesitant to mention this, as I don't wish to start an arguement over one db....and since we mostly discuss power......but, unfortuantely Eric, you misspoke here.....

A 3db change in power is NOT the same as a 3db change in voltage....
(we use the 10 log eq for power, and usually use the 20 log eq for voltage, as long as the impedances are the same, saving us some math steps....)


Power decibel calculations are:
db = 10 log (power 1 / power 2)

And....

Voltage decibel calculations are:
db = 20 log (voltage 1 / voltage 2)


Here, by happenstance, is a page that can help others understand this....the ironic thing here is, I was discussing this on 75m on night, a few years ago, and a longtime friend of mine decided to put some things on-line, and this is HIS response to my ramblings.....he added this to his pages.....
Decibel Calculations - POWER & VOLTAGE


But, if someone wishes for a more mainstream source of info, there's google and wikipedia.....
Gain - Wikipedia, the free encyclopedia
Gain - Wikipedia, the free encyclopedia

and even more details....
Decibel - Wikipedia, the free encyclopedia
Decibel - Wikipedia, the free encyclopedia


Hope this clears up things a bit.....


Fair winds....

John, KA4WJA
s/v Annie Laurie, WDB6927
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Old 23-08-2011, 14:33   #36
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Re: Ham on a Budget

John, a dB *is* a dB. The 20log (for voltage) vs 10log (for power) simply reflects the fact that power is relative to voltage-squared.

Start with 1W in a 1 Ohm load. E = Sqrt(P * R), E = 1V
Now double the power to 2W: E = Sqrt(P * R), E = 1.414V

20Log(1.414V / 1V) = 3dB
10Log(2W / 1W) = 3dB

Looking at it from the Voltage perspective, start with 1V across 1Ohm

P = (E**2) * R, P = 1W

Double the Voltage
P = (2V**2) * 1 Ohm, P = 4W

20Log(2V / 1V) = 6dB
10Log(4W / 1W) = 6dB

I think we are saying the same thing: using Voltage, we calculate dB as 20Log(V1/V2). Using power, we calculate as 10Log(P1/P2).
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Old 23-08-2011, 14:43   #37
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Re: Ham on a Budget

Yes, Paul, you and I are saying the same thing.....and yes, I'm well aware of how voltage-squared is related to power.....
I just wanted to make sure others didn't confuse a 3db change in power as the same as a 3db change in volatge.....

What I did not want to do is start a long, discussion about math....


All my best and fair winds....


John
s/v Annie Laurie
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Old 23-08-2011, 15:07   #38
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Re: Ham on a Budget

Speaking of radio issues, I've heard that some of the best Icom mobile ham rigs really prefer to see 13.8V on the power supply, and at 12-12.5 (typical boat battery voltage) they get really cranky as distortion goes up and output goes down.

Just something to consider before buying any ham radio that will be run off battery power, some really are spec'd for twelve volt use, others will not be happy there.
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Old 23-08-2011, 15:15   #39
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Re: Ham on a Budget

Not a problem with the 718. Transmitted and recieved fine with under 12volts on the ammeter. No sun for the first 10 days of my Transpac and knew the sun was going to come out, some time, so didn't run the engine to charge the batteries.

Since marine and ham radios pretty much use the same componenets to generate the signal, doubt that a marine Icom would be any better than ham rig.
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Old 23-08-2011, 15:21   #40
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I have an icom 7000 and a 700pro and don't have any problems with low batteries using either of them, say down to about 50+%. The 700pro puts out 150 watts all the time, but I can control the 7000 and either go with 10 or the full 100, depending on propagation. I really like all the filters too, but it's ham only...
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Old 23-08-2011, 15:38   #41
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Re: Ham on a Budget

Quote:
Originally Posted by ka4wja View Post
I just wanted to make sure others didn't confuse a 3db change in power as the same as a 3db change in volatge.....

What I did not want to do is start a long, discussion about math....
Fair enough, but a 3dB change in power is *exactly*the*same* as a 3dB change in voltage.

Tell you what, rather than continue to hijack this thread I will start another on the definitions and calculations of the various forms of decibels. You are welcome to join in the discussion (if there is anyone besides myself, who finds this stuff interesting.)
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Old 23-08-2011, 15:41   #42
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Re: Ham on a Budget

Quote:
Originally Posted by hellosailor View Post
Speaking of radio issues, I've heard that some of the best Icom mobile ham rigs really prefer to see 13.8V on the power supply, and at 12-12.5 (typical boat battery voltage) they get really cranky as distortion goes up and output goes down.

Just something to consider before buying any ham radio that will be run off battery power, some really are spec'd for twelve volt use, others will not be happy there.
FWIW, my Icom 746 ham rig just rolls back the power if the voltage drops... no distortion.

73 de Jim N9GFT/VK4GFT
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Old 23-08-2011, 16:19   #43
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Re: Ham on a Budget

I did not misspeak. I did not say that a 3db change in voltage is THE SAME as a 3db change in power. I said a 3db change in voltage IS a 3db change in power. I know about the different formulas. People have it in their mind that there is a "voltage db", and/or "power db" and that you have to differentiate between the two. You don't, there is no "voltage db" nor is there really a "power db" as a db by definition is used to represent relative differences in signal power. Increase the voltage level of your output by 3db, you've just increased your power level by 3db.

Eric
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Old 23-08-2011, 17:06   #44
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Re: Ham on a Budget

Well, Eric, please accept my apologies....it seems it was I who "misread"......(can I blame the internet??

(But, my orginal instinct was probably correct.....as I wrote I didn't wish to argue about db's, and it seems that's what happened)



What I'd like to do is also apologize to Drew as well.....as I believe all this is distracting to him and others looking for good ideas and advice.....
So, with all the sincerity possible on the internet, Drew please accept my apologies for drifting this far afield......


Seriously, Drew please don't let this drift distract you.....and in true ham spirit, 73....



John
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Old 24-08-2011, 16:15   #45
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Re: Ham on a Budget

On the power output vs. input voltage question, I just ran a little test with my ICOM IC-7000, a modern 100 watt HF/VHF radio designed for mobile operation. This was in CW mode at 7.100 mHz into a 50 ohm dummy load at three power settings, with RF power measured and displayed by an MFJ-993 autotuner. The variable power supply was an Astron VS-35M and voltages and current were measured by a separate inline digital meter. V_S is no load voltage at radio input, V_R is voltage at the radio during key down, Amps is power draw during key down, and Power of course is measured RF power output of the radio into the dummy load.

ICOM IC-7000 Power Output vs. Input Voltage

100%
V_S V_R Amps Power
14.0 13.5 19.0 115.0
13.0 12.5 17.3 92.0
12.0 11.6 15.3 66.0

50%
14.0 13.6 14.7 56.0
13.0 12.6 14.2 50.0
12.0 11.7 12.4 37.0

25%
14.0 13.8 11.8 28.0
13.0 12.7 11.5 27.0
12.0 11.7 10.5 20.0

As one can see, power output with this radio does go down as input voltage drops, and it happens more dramatically when the radio is trying to produce higher power outputs.

If you have the radio set to produce full power, and you modulate with voice or a Pactor modem at high levels with low radio input voltages, there is going to be clipping and distortion of the RF output. I've seen this happen with my radio, and it was manifested by wild swings in the apparent SWR during operation, an indication of a high amount of spurious RF energy and band splatter. Not to mention failure to make a Pactor link!

If you under-modulate the radio, this is much less likely to happen - which is probably why some haven't seen a problem with low input voltages.

I can't speak with experience about other radios, but I doubt the the entry level ICOM IC-718 does any better in this respect than the IC-7000. I would venture to guess that most ham radios will behave in a similar fashion, but not all do. I have an Elecraft K2, which is a 10+ watt radio that is designed to operate very well down to about 10 volts input, but it is not a high power radio and is designed specifically to do well under low voltage conditions.

Chip
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