[TowerTalk] Measuring Coax Loss

Thu Feb 11 17:59:10 PST 2010

I'm totally with you there.  If it comes to improving something, antennas
get the most bang for the buck.  But I just can't see spending money over a
dB or two... especially when I have competing interests.  I guess if I
really cared about DXCC and working #338 (or how ever many it is now), I
might think about it... but a dB or two will never be my breaking point.

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Dan Schaaf
Sent: Thursday, February 11, 2010 8:56 PM
To: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] Measuring Coax Loss

I do not have the test equipment that would let me run those tests.
That is why I pay attention to losses external to the radio.
And I cannot afford the radios on the market today. So, my paltry bucks go 
into things I  have control of, antenna and coax and connectors.

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 at cox.net>
To: "'Tower and HF antenna construction topics.'" <towertalk at contesting.com>
Sent: Thursday, February 11, 2010 8:51 PM
Subject: Re: [TowerTalk] Measuring Coax Loss

> Dan,
>
> Just out of curiosity, have you checked the sensitivity your 'legacy' rigs
> against something new?  Aren't you losing a dB or two there?  Just more
> fodder!
>
> So... how much IS that dB worth?
>
>
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com] On Behalf Of Dan Schaaf
> Sent: Thursday, February 11, 2010 8:48 PM
> To: Tower and HF antenna construction topics.
> Subject: Re: [TowerTalk] Measuring Coax Loss
>
> OK, it is now  in perspective.
> Presently, I use an 11 year old radio FT-920 for the  last 108 countries 
> and
>
> used an older FT-101ZD previously for the first 200 .
> These radios are all fine radios without the  bells and whistles of the
> newer rigs, IF DSP etc.
> But it all means nothing, to me,  if the losses in the antenna and coax 
> are
> high.
>
> KH7XS,Hi Bill.
>
> 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 at cox.net>
> To: "'Tower and HF antenna construction topics.'" 
> <towertalk at contesting.com>
> Sent: Thursday, February 11, 2010 8:42 PM
> Subject: Re: [TowerTalk] Measuring Coax Loss
>
>
>> 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 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.
>>
>>
>>
>>
>> -----Original Message-----
>> From: towertalk-bounces at contesting.com
>> [mailto:towertalk-bounces at 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 at cox.net>
>> To: "'Tower and HF antenna construction topics.'"
>> <towertalk at 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 at contesting.com
>>> [mailto:towertalk-bounces at 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 at cox.net>
>>> To: "'Tower and HF antenna construction topics.'"
>>> <towertalk at 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 at contesting.com
>>>> [mailto:towertalk-bounces at 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 at cox.net>
>>>> To: "'Tower and HF antenna construction topics.'"
>>>> <towertalk at 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 at contesting.com
>>>>> [mailto:towertalk-bounces at 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 at audiosystemsgroup.com>
>>>>> To: "Tower and HF antenna construction topics."
>>>>> <towertalk at 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 at contesting.com
>>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>>
>>>>>
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