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Author Topic: 75 Meter & Weak Signals  (Read 9855 times)
N3OX
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« Reply #15 on: September 19, 2007, 01:59:33 PM »

"Who care if you impress anyone... it's about making contacts isn't it"

Not in old-fart ragchew circles on 75m.

Look, if ever in my occasional foray to 75m fone I hear you calling CQ on 75m I'll give you a call.  We may be both a little down in the noise with our 100W but I'll swing the flag around to you so I can hear you a little better...

... but the thing is, not everyone wants to work for a contact.  Some guys want to have telephone-quality conversations with their buddies on 75m.

I think this thread probably started because the kilowatt alley ragchewers are the DX of the stateside world... what do I mean?

They are some of the loudest signals out there.  I can put up a 40m dipole at 10 feet, "tune it up" with my MFJ tuner on 75m, and STILL hear these guys 10dB over S9.

Hell, I can probably hear them at S7 with a screwdriver (the tool, not the antenna) plugged into my HF preamp.

It's because they're running full legal limit (or ... dare I suggest... more) into a high, efficient antenna.

Now I'm there with my 40m dipole fed with 50 feet of RG-8/X listening to this 59+10dB signal thinking "wow, I can easily work this guy... " but little do I know he'd be 59+26dB without the 16dB loss in my feedline...and when I come back to him, I'm TWENTY-EIGHT dB down from his buddies running 1500W into 99% efficient antenna systems.

Now, reciprocity demands that the actual deficit between my hearing him and his hearing me is just the 12dB going from 1500W to 100W... but I'm still nearly 30dB down from the people he's talking to.

So, now we've established that I'm piss-weak compared to his buddies.  Doesn't ham spirit demand that he talk to me anyway?

I dunno... maybe he DID cheerfully pass out contacts to the first 100 stations running a 40m dipole and 100W who broke into his ragchew looking for a signal report.  Then he willingly passed out the next 200... reluctantly did the next 500... but after 800 times that some @#(*$^#(* guy with 100W and a 40m dipole broke in...

Get the picture?

Look, I don't like cliques on the radio, I don't like the people thinking you have to run full legal limit to be loud (obviously, you don't always... ) but I *don't* think that everyone on 75m should be obligated by ham spirit to dig out your weak signal if indeed you have a weak signal.

I think the really loud guys on 75m are probably absolutely swamped with really weak guys looking to test out their radio, and that would get tired after a while if what you want to do is have armchair-copy QSO's with people you know.

And if you really DO want to break into a loud ragchew group... lie about how much power you're running and don't say "G5RV"

That will make them tolerate a weaker signal much better.. stupid but true.

73,

Dan
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
N3BIF
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« Reply #16 on: September 19, 2007, 08:53:36 PM »

So I guess 160 is definitely out of the question for any barefooters.  Then why do they bother putting 160 on HF rigs only capable of 100 watts?
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ONAIR
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« Reply #17 on: September 20, 2007, 12:18:45 AM »

    I remember many years ago, I had a friend who bought an old Lafayette HE-20C tube CB radio from his buddy for $20 bucks.  Being a 14 yo kid he couldn't afford to buy an antenna, so he threw a piece of wire out the window.  The guys in the neighborhood all had nice CB rigs with big Antenna Specialist "Super Magnums" or Shakespear "Big Sticks" on the roof.  When my friend tried to get a break and join in the conversation, they called him a "Wimp" and a "Mud Duck", and stepped all over him.  It's appalling to hear that the power guys on 75 meters are treating some of the weaker ham stations the exact same way today!  By the way, my friend eventually got a 4 element CB beam and a 500 Watt linear. and blasted all of those rude big shots right off the frequency!
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KB9CRY
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« Reply #18 on: September 20, 2007, 08:03:38 AM »

Then why do they bother putting 160 on HF rigs only capable of 100 watts?

Because you use that to drive your amp.
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KE3WD
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« Reply #19 on: September 20, 2007, 10:21:27 AM »

>>Then why do they bother putting 160 on HF rigs only capable of 100 watts?<<

Also because there are a few individuals who have the real estate to erect a huge loop, Beveridge, loaded long tall tower, etc. and can indeed run 100W on top band with success.  

But mostly because of marketing.  

New hams are enamored with DC to Daylight rigs, plain and simple.  

Not understanding the tradeoffs inherent in such, the things sell very well.  


KE3WD
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N5GLR
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« Reply #20 on: September 20, 2007, 09:13:48 PM »

Most of the responses here are about what I expected.  Knowing the mentality of the folks who haunt these posts waiting to leap into action and display their ignorance ... I'm not surprised at all.

A couple of folks here "get it" but, most don't and don't want to.  They just want another opportunity to rant and rave about how unfair it all is.

Here's a question for all of you "logic" challenged folks to answer ... How long are you willing to try to hold a conversation with someone you can only hear about 80% (or less) of the time?  
Put another way ... how long were you willing to talk to someone who was not full quieting into the repeater?
   
It ain't about who's the biggest "gun", it's about being able to hold a QSO ... which is something most of you here don't understand.  Contact = signal report. Can't hear you well = contact.  I can hear you comfortably above the noise = QSO = conversation ... as in discussion.

You "new to HF folks" need to change your mind-set. You're not on the local repeater system anymore with full quieting signals.  HF is all about propagation and signal strength and competing with noise and propagation to be heard. Many times you're competing with other stations to be heard by a DX station.  

Here' another thing ... Other than for emergencies, the rules don't require anyone to acknowledge you.  You can call 'til you're blue in the face and folks can ignore you at their will.  Don't come on any frequency thinking you deserve to be acknowledged just because you announce your call or ask for a break.  

By the way ... if you don't operate HF, this discussion doesn't concern you so, butt out.
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N3OX
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« Reply #21 on: September 21, 2007, 04:08:14 PM »

"New hams are enamored with DC to Daylight rigs, plain and simple.

Not understanding the tradeoffs inherent in such, the things sell very well.
"

I have 39 countries worked on 160m with 100W.  Most of the Europeans worked on 160m were worked using a barefoot FT-857D...

'course that's 100W CW... but some people work 160m QRP too!

I've made several contacts with the really really loud guys in the 75m / 80m DX windows with 5W.  Got a 579 report and a real QSO; easy back and forth with the info with F5IN on 80CW using 5W.

It's unlikely you'll make it all the way to signal parity with a guy running 1500W into any reasonable antenna on 160m unless you're running a little power, but if you can put up a real antenna... say a full size quarter wave with lots of radials... you can probably get to within a handful of dB of the guy running 1500W into his inverted L with 3 ground radials.

Now, that's a little silly... if you're going to spend that much money and/or effort on an antenna system for 160m, you might as well back it up with an amplifier... but you can use your 100W on 160m just fine until you can get an amp.  And a good antenna can make 800W from a low-priced HF amp sound like someone else's 1500W into a lesser antenna.

Just don't go putting up a really crappy antenna and trying to break into N5GLR's ragchew.  

Do something fun instead, like slip down to 1834 CW and work DF2PY.  He can hear EVERYBODY ;-)

The thing I'd say is most important about the low bands, is for god's sake, don't use your dipole for a low band on the next one down.  It just doesn't work.  Your tuner is almost guaranteed to handle it fine... and that may be why so many people make this mistake, but it just doesn't radiate much power!!!

73,
Dan





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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
N5GLR
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« Reply #22 on: September 21, 2007, 05:47:49 PM »

N3OX said ...
"Just don't go putting up a really crappy antenna and trying to break into N5GLR's ragchew."

He's right folks ... not if you want to "ragchew".  If you want a quick "contact", which seems to be the way of things these days, and I can hear you on your "crappy antenna", I'm happy to oblige.  However, it gets very uncomfortable on the ears trying
Otherwise, drop down to 160 mtr. and join N3OX in his QRP DX chasing.  

N3OX has made another good point.  Your antenna needs to be cut for the band ...  not half size.  Don't expect your 40 meter antenna to perform well on 80 ... it won't.  It's about "radiating area" and "capture area".  An antenna only half as long as it should be will not "capture" the same amount of signal as a full size antenna (same is true for transmit).

For those who enjoy CW, as I do, you still need a decent antenna.  The less power you run, the more important your antenna becomes ... the more efficient it must be.  By the way, ragchews occur on CW also.  I've had some very enjoyable QSOs with folks I've met on the air for the first time ... on phone and CW.  I happen to enjoy phone, CW, ragchews, & DX.  I haven't counted the number of CW contact I've made but, I know it' well over 1,000 and maybe half of those are DX and maybe half of those are QRP.  

The addage is ... whatever amount of money you plan to spend on an HF station, spend 90% of it on your antenna system and the remainder on a radio.
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N3OX
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« Reply #23 on: September 22, 2007, 11:40:16 AM »

"Your antenna needs to be cut for the band ... not half size"

I would say that if it's half size, you have to load it with good coils, that's what I'd say.
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
N3OX
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« Reply #24 on: September 22, 2007, 11:40:22 AM »

"Your antenna needs to be cut for the band ... not half size"

I would say that if it's half size, you have to load it with good coils, that's what I'd say.
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
VA3XQ
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« Reply #25 on: September 22, 2007, 12:28:26 PM »

I think there are other ways to get the signals out as well with the station most people have. Audio, most audio is not that clear, muffled, lots of lows, background noise etc. Clean this up and speak clearly and that will go a long way. I added a 2 band equalizer and use a Heil mic to be sure I can get the most punch from my audio. Much cheaper than a new amp. Use headphones, cannot imagine not wearing them to hear other stations especially on 75. It just makes that much more of a difference. And use standard phonetcs, the ones we all had to learn to get our tickets. Stick to that, thats what other operators expect to hear. Not some made up out of your hat phonetic. All these are cheap fixes and will go  along way to getting the contact made. Transmit audio is definetly a big one to work on and you will see immediate success once this is fixed up.
jeff
va3xq
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KE4ZHN
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« Reply #26 on: September 22, 2007, 01:04:33 PM »

I will work anyone I can reliably copy regardless of what their running. What many dont seem to understand or want to understand is, the noise floor and propagation of 75 is such that many times you just need to run an amplifier into a full sized antenna. This hasnt got anything to do with being a power monger or a  cb'er its just the plain hard facts that its a tough band to work with a compromise station, period. Some winter nights you can work fine barefoot on 75. And many times during the winter I do leave the amp off. The band changes constantly and sometimes you just need the extra punch to be heard. Why does this upset the power police and amp haters so much? We're supposed to run the minimum power for communications and sometimes when the noise level is S9+20-30 this happens to be legal limit. If you cant work the band properly then dont expect to be welcomed with open arms when your signal is 40 db below the noise floor. It would be like someone trying to run qrp on 160 in mid summer into a hamstick getting pissed because nobody will answer their call. Use the right tools for the job and youll get much better results. If you dont know what those tools are, ask around or research it online. Your 75 mtr. experience will be much more enjoyable.  
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ONAIR
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« Reply #27 on: September 22, 2007, 06:04:54 PM »

    This reminds me a little of a ham I heard a few years back.  He was trying to keep up with the conversation on 75m, but he got really annoyed when a newbie located a mile away tried to talk to him.  He came right out and said to the kid...  "I won't talk to you now because you are too damn strong"!
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KB9CRY
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« Reply #28 on: September 23, 2007, 05:33:36 AM »

Now, that's a little silly... if you're going to spend that much money and/or effort on an antenna system for 160m, you might as well back it up with an amplifier... but you can use your 100W on 160m just fine until you can get an amp. And a good antenna can make 800W from a low-priced HF amp sound like someone else's 1500W into a lesser antenna.



Well the real thing about the lowbands, and especially 160M is that most of the top guys, even those with super transmit antennas and amplifiers, also have separate receiving antennas also.  You'll find that most good transmit antennas for the low bands are also lousy reception antennas.

You can't work them unless you can hear them.  The amp allows others to hear you better for sure but you also need to be able to hear them; it's a two way street.

Here's a link to a nice compendium of low band receiving antennas that everyone should be able to erect with little cost.

http://www.angelfire.com/md/k3ky/page20.html


So those of you with the marginal transmit antennas, you may want to try one of these to augment your setup.  Usually, if you can hear them, they ought to be able to hear you.

Word of Warning:  Most low band net operators, my own opinion of course, don't have good receiving antennas and they get by by cranking up the watts with each other.  I'm talking DXing only in my above comments.
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N3OX
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« Reply #29 on: September 23, 2007, 08:08:27 AM »

"Usually, if you can hear them, they ought to be able to hear you."

At 1500W, yes.. you should be able to work them if you can hear them.  At 100W...

I'd say the rough percentage for me on 80m is if I can hear them, they can hear me 75% of the time.

On 160m, if I can hear them, they can hear me maybe 50% of the time.

This is a good message for the low band guys with only 100W.  If you can work even half the DX you hear, it's going to be fun!  

- - - - - - -

Phil's point about RX antennas should be taken very seriously, in the sense that for DX, there's often the opposite problem that N5GLR has.  The DX is really weak, we're all straining to hear him.  If you don't really hear him but keep throwing in your call hoping that the faint peeping will come back as something you recognize, and we all hear the DX coming back to you over and over again without you noticing, you're not going to be a very popular guy.

Dan







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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
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