[Top] [All Lists]

Re: [TowerTalk] TowerTalk Digest, Vol 117, Issue 9

Subject: Re: [TowerTalk] TowerTalk Digest, Vol 117, Issue 9
From: Roger D Johnson <>
Date: Tue, 04 Sep 2012 16:01:01 -0400
List-post: <">>
Hi Jim...

I'm used to the old Tek pulse type TDRs. What would be the effect on the trace of a swept frequency TDR with FFT when the line is terminated with an antenna with several resonant points, such as Roger's? The one trace I saw on the Array Solutions site for the AIM 4170 looked fine but the load was a resistive.

73, the other Roger

On 9/4/2012 1:17 PM, Jim Brown wrote:
On 9/4/2012 10:00 AM, Spencer wrote:
You need a FAST rise time pulse generator with variable repetition rate and pulse width. A good scope. A test setup. ANY Z discontinuities will cause a reflection and will show up on the scope trace.

There are several ways to skin this particular cat. That's one of them. Transforming a frequency sweep is another, and has been widely used in the pro audio world for at least 30 years. One of the major advantages is signal to noise level. Another is that you can limit the response to the frequency range in which you are interested. For example, small discontinuities that would be more problematic at UHF can be ignored by using a sweep that only goes to 100 MHz, and those discontinuities emphasized by using a sweep that begins at 100 MHz or or so and sweeps to a higher frequency.

73, Jim K9YC


TowerTalk mailing list

Remember the Liberty (AGTR-5)


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>