Yeah, I did not jump in to argue and also why would you spend $1000 for an
antenna and use RG58!! We can definitely add on the website “RG213” of good
quality used if it makes folks not get confused.
The swr curves shown are for “reference” purposes only. An swr curve at QTH “A”
will be be slightly different at QTH “B” depending on height above ground,
surrounding structures, other antennas, etc etc.
The analyzer is a RigExpert and it seems to be working fine. Maybe you should
ask RigExpert why there seems to be a small drop at the measured edges. The
image was taken from the Antscope software.
If someone doesn’t like what data is presented, then they have a lovely choice,
go buy another manufacturer’s products. There are many good choices out there.
Its a healthy competition.
I can only tell you that so far, I have not come to this forum even once to
announce or talk about our antennas (i just signed up today to towertalk). Our
customers come and buy and evangelize our antennas because they get exactly
whats claimed as specs by us and also they love it because of the mechanical
construction and high-quality parts used.
Thanks for all the input. Happy Thanksgiving.
On Nov 27, 2014, at 4:38 PM, Joe Subich, W4TV <lists@subich.com> wrote:
> There is not much significant difference
It depends ... perhaps with quality RG-213 where loss is ~1 dB/100'
at 30 MHz the difference is not significant. However, if you're using
RG58 with nearly 3 dB/100' at 30 MHz even a non-resonant antenna begins
to look good. Your web page does not specify the type of coax and loss
thus "at the feedpoint" measurements are more appropriate.
I do not trust the presented curves in any case - each band shows an
anomalous drop in the last few measurement points. This behavior would
indicate a faulty measurement device, inappropriate date manipulation
(smoothing/averaging), or some potential loss/resonance in the system.
73,
... Joe, W4TV
On 2014-11-27 2:30 PM, Ken Garg wrote:
> Joe,
> All data is available at 50ft, 100ft etc. There is not much significant
> difference thats smoke and mirrors. The reason to show 100ft was taking into
> account an average ham shack with a coax run. Do you think there will be a
> significant difference in swr between 100ft and 50ft? Ot do you think that
> our coax has so much loss that we don’t see swr? Not sure of your point. If
> measured swr at the feed point is 1.28:1, then the measured swr at 100ft will
> be approx 1.2:1 using RG213 as a coax.
> The goal was to show a freespace design vs actual measured for the average
> ham on a simple page. If someone needs more details, they can always ask in
> an email through the website.
>
> Thanks,
> Ken
>
> On Nov 27, 2014, at 2:12 PM, Joe Subich, W4TV <lists@subich.com> wrote:
>
>
>> The swr curves for this antenna assembled out of the box at 36ft is
>> presented here .. http://jkantennas.com/navassa-5-data.html
>
> If the antenna is at 36 feet, why are you using 100 feet of coax for
> the measurement? Why not use 50 feet or calibrate out the losses and
> present true "at the antenna" measurements?
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2014-11-27 12:34 PM, Ken Garg wrote:
>> Happy Thanksgiving all !!
>> A good friend alerted me to a posting by K9OM. His post starts as follows
>> ..”Correct me if I’m wrong …”. Well, Dick you are WRONG.
>> The JK Navassa-5 comes pre-drilled, pre-cuts tips from the factory. The user
>> just needs to assemble the antenna. These antennas are made of the best
>> quality hardware and rated heavy-duty. There are many other quality
>> manufacturers in the Yagi antenna space and the Hams are left to some good
>> choices. If you like the JK construction with machined saddles, and quality
>> hardware, including the “mast plate" all available for $1185 compared to
>> others, then you will buy this antenna. The JK construction and mechanical
>> robustness speaks for itself and folks that have it will speak to it. The
>> swr curves for this antenna assembled out of the box at 36ft is presented
>> here .. http://jkantennas.com/navassa-5-data.html
>>
>>
>>
>> _______________________________________________
>>
>>
>>
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