Mike Besemer (WM4B) wrote:
> But let's put it in perspective.
>
> Suppose you're putting up a new antenna system and have two 100' lengths of
> coax to choose from, one of which has 1dB more loss than the other.
>
> How much is that 1dB worth to you? 10 cents/foot? 20? 50? Suppose you
> have to make the same choice for 4 or 5 runs of the same coax. Where do you
> draw the line?
>
> I certainly get your point... I think the question is, where is the point of
> diminishing returns?
>
>
I think it's not the point of diminishing returns but rather what
compromise is the individual willing to settle for. IOW would you pay $1
more per foot, $2.00, $3.00, $5.00, or where would the individual draw
the line on those diminishing returns. I started with good RG-8, then
went to 9913, then LMR-400, and currently with LMR-600. Next step? 7/8"
Heliax for each run to the tower and up the tower? Probably if I come
across some at a good price...IE, pull out from a commercial station
that's been swept. How much are you willing to spend for power? You can
get the legal limit for close to $1000 used and go all the way to an
auto tuning alpha that runs close to ten grand. Is the $800 plus Yaesu
897D good enough or are you willing to go $13,000 for their best
transceiver. What if you spend at least as much time in your shop as the
house like I do. Would you get the versatility of the 897D and carry it
back and fourth, get two of them and spend the bucks to set up a SO2R
station? I've had both the 897D and the 7000. Hated them both although
they'd make great mobile rigs.
Like many on here, my interest is in antennas, towers, and feed lines
and *probably* most of us would spend more on the antenna and feed line
than is installed in the typical station.
Some individuals would spend big bucks to get that 1 db. I really need
to put the story up about WD8RXP's home brew, self supporting tower.
The story was in QST (I had the cover shot) as the "Mid Michigan
Skyhook" written by Norm Keyon (WA8AEG) now W8AWE. IIRC John had
something like three semi loads of steel in that tower and over $30,000.
John passed away a few years back and they couldn't even give the tower
away. It was even on e-bay with no bids. That system was small potatoes
compared to some that have been listed on here such as those self
supporting towers large enough to support a 4L 75 meter beam large
enough to walk "inside" the boom. Add to that the extra money for a
big beam...say monobander and the structure to support and turn it for
another db. Suppose the individual is willing to take the risk of not
grounding the coax at the top and bottom of the tower so they eliminate
the cost and loss (a few tenths of a db) for those extra connectors
who's sole purpose is safety. They could be putting their entire station
on the line just for a few tenths of a db.
> I have a different perspective. Aside from my time when I was a kid, I
> never had a 'decent' antenna system. I moved every couple of years for the
> 24 of the past 29 years. I used low wires and whatever else I could put up.
> I have confirmed over 200 countries and never applied for DXCC because it's
> not important to me.
>
> How much would I pay for that extra dB? Not a cent.
>
I think that is one of the great things about ham radio. You can put
into it what you want and you and strive to get out of it what you wish.
There is a place for virtually every budget. income, and most
personalities. There are probably as many answers to the original
question of what would you spend for that extra db as there are
hundreds,or possibly over a thousand who are on, or follow Tower Talk. I
would add to the question as to how much more would you be willing to
spend, "how much extra work, and why".
73
Roger (K8RI)
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Dan Schaaf
> Sent: Thursday, February 11, 2010 8:33 PM
> To: Tower and HF antenna construction topics.
> Subject: Re: [TowerTalk] Measuring Coax Loss
>
> I spend most of my waking hours working DX. And since I have worked 308
> countries on most bands, I hunt for those that I have not yet worked on
> certain bands. Tonite for example I worked DU9 on 15 meters SSB. Koichi was
> just above the noise except for some QSB when he dropped in/out. Most of
> what I need is weak. I did the 308 countries during the last 5 years when
> the SSN was in decline.
>
> Best Regards
> Dan Schaaf
> K3ZXL www.k3zxl.com "In the Beginning, there was Spark Gap"
> ===============================
> NOBSKA
> www.nobska.net
> ===============================
> Cape Cod Instruments
> www.oceanbiz.net
> ===============================
> ----- Original Message -----
> From: "Mike Besemer (WM4B)" <mwbesemer@cox.net>
> To: "'Tower and HF antenna construction topics.'" <towertalk@contesting.com>
> Sent: Thursday, February 11, 2010 8:26 PM
> Subject: Re: [TowerTalk] Measuring Coax Loss
>
>
>
>> How, it the real world of ham radio, do you experience hearing the
>> difference of 3dB daily?
>>
>> I'm not talking about a lab.
>>
>>
>>
>> -----Original Message-----
>> From: towertalk-bounces@contesting.com
>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Dan Schaaf
>> Sent: Thursday, February 11, 2010 8:24 PM
>> To: Tower and HF antenna construction topics.
>> Subject: Re: [TowerTalk] Measuring Coax Loss
>>
>> I am not " thinking what I want". I know this to be fact.
>> I experience it daily.
>> Nobody is disqualifying you or accusing you of stupidity. There is a
>> difference between stupidity and ignorance. Ignorance is "not knowing or
>> not
>>
>> having been educated". Stupidity is knowing and still being defiant of the
>> knowledge.
>> You come to this and other groups for knowledge.
>>
>>
>> Best Regards
>> Dan Schaaf
>> K3ZXL www.k3zxl.com "In the Beginning, there was Spark Gap"
>> ===============================
>> NOBSKA
>> www.nobska.net
>> ===============================
>> Cape Cod Instruments
>> www.oceanbiz.net
>> ===============================
>> ----- Original Message -----
>> From: "Mike Besemer (WM4B)" <mwbesemer@cox.net>
>> To: "'Tower and HF antenna construction topics.'"
>> <towertalk@contesting.com>
>> Sent: Thursday, February 11, 2010 8:13 PM
>> Subject: Re: [TowerTalk] Measuring Coax Loss
>>
>>
>>
>>> Think what you want, Dan... I stand by my argument that 99% of the time
>>> 3dB
>>> is inaudible.
>>>
>>> I love the sanctimonious attitude on this list. If somebody disagrees,
>>> they're automatically unqualified or stupid.
>>>
>>> That's why I left last time.
>>>
>>>
>>> -----Original Message-----
>>> From: towertalk-bounces@contesting.com
>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Dan Schaaf
>>> Sent: Thursday, February 11, 2010 8:07 PM
>>> To: Tower and HF antenna construction topics.
>>> Subject: Re: [TowerTalk] Measuring Coax Loss
>>>
>>> A really serious DXer is concerned about these losses.
>>> Someone who casually operates may not care too much.
>>> The point is that all losses add up.
>>> I CAN hear the difference.
>>> For example. +/- 3 db is either 1/2 or 2 x the power whether transmitted
>>> or
>>>
>>> received. I can clearly hear the difference in a weak signal if itdrops3
>>> db
>>>
>>> or raises 3 db.
>>> I think that you are just repeating something that you heard and have not
>>> actually experienced these differences on the air.
>>>
>>>
>>> Best Regards
>>> Dan Schaaf
>>> K3ZXL www.k3zxl.com "In the Beginning, there was Spark Gap"
>>> ===============================
>>> NOBSKA
>>> www.nobska.net
>>> ===============================
>>> Cape Cod Instruments
>>> www.oceanbiz.net
>>> ===============================
>>> ----- Original Message -----
>>> From: "Mike Besemer (WM4B)" <mwbesemer@cox.net>
>>> To: "'Tower and HF antenna construction topics.'"
>>> <towertalk@contesting.com>
>>> Sent: Thursday, February 11, 2010 8:01 PM
>>> Subject: Re: [TowerTalk] Measuring Coax Loss
>>>
>>>
>>>
>>>> I qualified my comments to exclude microwave/weak signal work.
>>>>
>>>> If you have that many connectors in-line, how concerned are you REALLY
>>>> about
>>>> loss?
>>>>
>>>> C'mon guys... for HF and probably VHF, it isn't that critical.
>>>>
>>>> WM4B
>>>>
>>>> -----Original Message-----
>>>> From: towertalk-bounces@contesting.com
>>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Dan Schaaf
>>>> Sent: Thursday, February 11, 2010 7:45 PM
>>>> To: Tower and HF antenna construction topics.
>>>> Subject: Re: [TowerTalk] Measuring Coax Loss
>>>>
>>>> Having been a calibration Engineer in my early days, I concur with Jim.
>>>> In addition, each coax connector inline introduces losses. They all add
>>>> up.
>>>> Definitely worse in VHF/UHF. Some folks say you can't hear the
>>>> difference,
>>>> but when you are trying to hear and work a weak signal in/above the
>>>> noise,
>>>> every db counts.
>>>>
>>>> Dan Schaaf
>>>> K3ZXL
>>>> "In the Beginning there was Spark Gap"
>>>> www.k3zxl.com
>>>> ----- Original Message -----
>>>> From: "Jim Brown" <jim@audiosystemsgroup.com>
>>>> To: "Tower and HF antenna construction topics."
>>>> <towertalk@contesting.com>
>>>> Sent: Thursday, February 11, 2010 7:34 PM
>>>> Subject: Re: [TowerTalk] Measuring Coax Loss
>>>>
>>>>
>>>>
>>>>> On Thu, 11 Feb 2010 19:03:51 -0500, Mike Besemer \(WM4B\) wrote:
>>>>>
>>>>>
>>>>>> Still... a dB or so (or even 3) on a long run of coax isn't going to
>>>>>> make a hill of beans difference for most applications... an S-Unit
>>>>>> is ~ 6dB.
>>>>>>
>>>>> Only by someone's definition, not in reality. If you actually MEASURE
>>>>> the
>>>>> response of the S-meters in REAL radios, you find that an S-unit may be
>>>>> close
>>>>> to 6dB near S9, but is usually closer to 3dB at S5 and below.
>>>>>
>>>>> As to a hill of beans -- many hams have long runs of coax to their
>>>>> antennas,
>>>>> so loss can be a BIG deal, not a hill of beans. The loss in dB of
>>>>> verious
>>>>> RG8
>>>>> style coaxes ranges by a factor of about 2:1 from the lowest to the
>>>>> highest.
>>>>> Over the past several years, I've been doing a lot of little things to
>>>>> improve my station. A dB here, a dB there, they all add up. Smart
>>>>> operators
>>>>> know that. The difference between a 3-el yagi and a 4-el yagi of
>>>>> comparable
>>>>> design is only 1-2 dB, and often double the cost. That doesn't stop a
>>>>> lot
>>>>> of
>>>>> guys who have the space from putting up 4-el yagis!
>>>>>
>>>>> Somehow, the scientific method seems to be lost on some of those
>>>>> commenting
>>>>> on my post. How do you know that the MFJ (or any piece of test gear) is
>>>>> accurate if you don't compare it to another measurement or test method
>>>>> of
>>>>> known accuracy? I'll bet a six pack of your favorite 807s that if I had
>>>>> posted loss measuerements made ONLY with an MFJ, someone would have
>>>>> pooh-
>>>>> poohed them because I didn't use equipment traceable to a calibration
>>>>> lab.
>>>>>
>>>>>
>>>>>> Forgot to mention... unless I actually SAW the 10' piece being cut off
>>>>>> the
>>>>>> longer roll I was considering buying from, I wouldn't trust the
>>>>>> measurements
>>>>>> anyway.
>>>>>>
>>>>> Did it ever occur to you that sometimes ham stores, even the best
>>>>> known,
>>>>> with
>>>>> the biggest ads in QST, may not have good data on what they're selling?
>>>>> I
>>>>> don't trust some of them any more than an anonymous vendor in a flea
>>>>> market.
>>>>> But there ARE some good deals out there, IF you have an open mind and
>>>>> know
>>>>> how to evaluate them. The point of my post was to show that you CAN get
>>>>> decent data from an MFJ259B that has been calibrated if you're
>>>>> measuring
>>>>> a
>>>>> sample that is long enough.
>>>>>
>>>>> How many measurements of coax loas have you actually made? How did you
>>>>> do
>>>>> it?
>>>>> How did you know that you had good data? At some point, you've got to
>>>>> know
>>>>> exactly how long that piece of coax is. RG8 is big and heavy, so
>>>>> unspooling
>>>>> enough of it to get a good measurement isn't always easy. You've got to
>>>>> deal
>>>>> with the length of cable sample you can get.
>>>>>
>>>>> 73,
>>>>>
>>>>> Jim K9YC
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>>
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