[HCARC] Antenna Coupler vs Antenna Tuner (Gary J's weekly test tosee if the Reflector is still working)

[Gary and Arlene Johnson]

Kerry -

So much information to process and remember.

If one were to run open wire line as the feed line from an antenna to a 
shack - what would the max run be and how does it need to be run.  I assume 
it can't be run through conduit and I also assume it can't lay on the 
ground.  Isn't there something about it not twisting or is it that it has to 
have a twist in it??  I am totally ignorant on the subject.

Gary J
N5BAA

----- Original Message ----- 
From: "Kerry Sandstrom" <kerryk5ks at hughes.net>
To: "Gary and Arlene Johnson" <qltfnish at omniglobal.net>; 
<hcarc at mailman.qth.net>
Sent: Saturday, December 22, 2012 7:58 PM
Subject: Re: [HCARC] Antenna Coupler vs Antenna Tuner (Gary J's weekly test 
tosee if the Reflector is still working)


> Gary,
>
> There is no best place.  If you have a manual antenna tuner and want to 
> operate on several different frequencies, you have to have it in the shack 
> and take the losses.  Reasonable lengths of good coax have little loss at 
> HF.  Open wire line as very low loss at any reasonable frequency.  Note 
> that antenna tuners are not without losses either,especially at lower 
> frequencies.
>
> I'll give you some antenna tuner loss data later, but first lets look at 
> typical ham station.  We'll consider three different types:   First an 
> all-band vertical antenna; second, a station with a multi-band dipole for 
> 80, 40, and 30 m and a tribander for 20-10 m; and ,third, a station with a 
> long wire for all bands.  What are the requirements for each station?  The 
> first station with the all-band vertical probably has 50 kHz bandwidth on 
> 80 m, perhaps 150 kHz bandwidth on 40 m and full-band coverage on the 
> higher bands.  If he is a CW operator, he probably doesn't need an antenna 
> tuner. Even on 80 m, 50 khz bandwidth is adequate.  If he operates phone, 
> then the bandwidth on 80 m is just plain inadequate.  On 40 and higher, it 
> will be OK.  So, the phone operator will need an antenna tuner to provide 
> adequate coverage on 80 m.  If the first operator operates both CW and 
> phone, then he will need a tuner for both full coverage of 80 and 40 m.
>
> The second operator will find himself in a similar situation.  The 
> bandwidths of the multi-band dipole on 80 and 40 m will be similar to that 
> of the all-band vertical.  On 30 m, the dipole will cover the whole band. 
> The tri-bander will cover all of 20, 15 and 10 m with no problem.  So his 
> situation is essentially the same as the first operator.  His need for an 
> antenna tuner will depend on his choice of CW, phone or both.  Also, if 
> his multi-band dipole doesn't cover the WARC bands, then he will need an 
> antenna tuner to cover those bands also.
>
> The third operator is in quite a different situation.  His ability to 
> operate on any band will depend on an antenna tuner.   Unless he is very 
> fortunate, he will always need an antenna tuner to operate on any part of 
> any band.
>
> QST for May of 1995 had an article titled "How to Evaluate Your Antenna 
> Tuner - Part 2".  This article looked at bandwidth and efficiency/power 
> loss of 4 different tuners: Heathkit SA-2040, Johnson 275 W Matchbox, 
> Johnson KW Matchbox and Collins 30S-1.  The Heathkit SA-2040 is 
> represenative/better than the typical T-match antenna tuners currently 
> available such as the MFJ antenna tuners (My opinion!).  The Johnson 
> tuners are primjarily designed for open wire balanced transmission lines 
> but can be used with coaxial cables.  The Collins is rare, expensive and 
> about as good as you can get (Again my opinion!).  Now for the results. 
> The Heathkit tuner had losses above 10 % no matter what the frequency for 
> low impedance loads, under 50 Ohm.  The worst cases were for loads with 
> SWR of 16:1, the losses were 50 % or more for every frequency and for 30 
> meters, it was 76%.  When used with the built-in balun, the losses were 
> even higher with a maximum of 86% loss at 80 m with a 16:1 SWR.  And you 
> ask why I don't believe in baluns!  By the way, a loss of 75 % is the same 
> as 6 dB of loss.  You get a quarter of the power to the antenna.
>
> The Johnson Mathboxes had much lower losses, generally under 10 % but a 
> couple places where they hit 15 %.  However, these matchboxes didn't cover 
> as wide a range of SWR and didn't cover 160 m or 30 m and had their 
> highest losses on the WARC bands which they were not designed to cover. 
> Note that the Johnson Mathboxes are much larger than the Heathkit SA-2040. 
> They use air wound coils and wide spaced air dielectric capacitors.
>
> The Collins 30S-1 is the best of the lot.  Its losses are under 10 % 
> except for a 16:1 SWR on 12 and 10 m.  It is the only one of the 4 tuners 
> to cover 160 m although its range is quite limited on 160 m.  It can only 
> handle unbalanced loads.and is qiuite large and heavy.
>
> I don't have any data on the automatic tuners, however, I don't trust 
> them. Specific concerns are the use of small solid dielectric capacitors 
> instead of large air dielectric variable capacitors and small coils wound 
> on cores instead of air wound/ceramic coil forms used by Johnson and 
> Collins.
>
> So, where does that leave us?  I believe a sensible antenna setup for an 
> all-band (HF) station is a matched multi-band dipole or vertical for 160, 
> 80, 40 and 30 m and either multiband dipole or vertical or tribander or 
> small single-band Yagis for whichever higher bands you are interested in. 
> A tuner is required to get complete band coverage of 160, 80 and 40 m.  At 
> these low frequencies, I don't think it matters where you put the antenna 
> tuner.  The biggest source of loss is the tuner unless you invest big 
> bucks in the tuner.  For the bands/modes you aren't serious about, then 
> using an antenna tuner to cover those bands/modes is a reasonable 
> compromise.  It will at least get you on>
>
> I won't even comment on e-Bay, but I consider e-Bay to be a 
> commie/terrorist plot.  It has completely ruined the old equipment market 
> for normal people. About all you can do is learn as much about the things 
> you are interested in as you can and then keep your eyes open as you 
> attend hamfests.  If you see something you're interested in, you think you 
> understand it and the price seems reasonable, then go for it.  By the way, 
> I don't think any key is worth $100.  For some, an unusual key is a status 
> symbol.  Note that you can use anything you want as a key, but tell your 
> contacts its some rare, gold plated, exotic key.  They can't tell the 
> difference.  You might not sleep as well at night, but you'll be a lot 
> wealthier!  You can also tell your contacts that you're portable in some 
> rare, exotic location.  They can't tell the difference in that either! 
> And, yes, it has been done.  A couple of DX'ers were permanently banned 
> from DXCC because of the number of rare countries they "operated" from 
> without ever setting foot there.
>
> Kerry
>
>
>
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