Yes, Chuck, I ran similar calculations and found that I needed to go with at least 7/8" heliax in order to be competitive with open wire line when trying to feed antennas with very high input impedan
Jim, et al: Make sure you are wearing hip wadder boots when you start reading the stuff submitted by the BPL lobbyists. A number of them clearly need to crack their physics textbooks for a refresher
Jim, et al: Make sure you are wearing hip wadder boots when you start reading the stuff submitted by the BPL lobbyists. A number of them clearly need to crack their physics textbooks for a refresher
This sort of goes along with both (a) and (e), but I worth reiterating. If you are running a horizontally polarized antenna, the choke will help to reduce the vertically polarized response added by
Fellow Reflectorites: Just a quick reminder that the deadline for filing comments in response to the FCC's Notice of Inquiry on Broadband over Powerline (BPL) is this coming MONDAY JULY 7, 2003. If y
Thanks for your very thought provoking comments, Jim. While I am not sure that I agree that large scale BPL rollout is a fate accompli, I do agree that it is important that reply comments address the
Scott, A couple of questions: 1) Where are you measuring the impedance - at the feedpoint or through a length of coax? 2) If through a length of coax, how long and what type? 3) Did you cross over th
Did you get the periodic variation in impedance (800 KHz to 1 MHz periodicity) when you measured from the top of the tower, or just when you measured from base with the 130' coax? I would try discon
Pete, get a gas tube grounding block. http://www.viewsonics.com/webapp/wcs/stores/servlet/ENPlevel2catView?categor yId=11257&catalogId=10013&storeId=10013&catalogId=10013&langId=-1 Click on Grounding
This brings up an interesting question, Jim. The gas tube ground blocks I mentioned are basically the same thing with a gas tube used in addition or in place of the air-gap. Since the aggregate RF vo
The type 77 material is notorious for having a poor loss tangent, hence the 60 deg phase angle. Type 61 material is much better, but the mu is much lower so you need bocque beads to get the same seri
The two I purchased are up high in the air, otherwise I would do as you suggested - hi hi. Mike, W4EF................................................................... numbers. Weather Stations", an
That's interesting, Joe. I thought type 73 and type 77 were both lousy in terms of loss tangent. In fact, when I looked up the tan(d)/ui numbers in my amidon catalog - they appear to me to be very si
I tried this a while back, but I had some little trouble with the compression fittings rotating around the hardline outer conductor. Anyway to cure this, or was it perhaps that the hardline I was usi
It sounds like an oxymoron, but what its referring to is cable TV that is delivered to subscribers using terrestrial microwave at 2.5 GHz. http://www.wcai.com/mmds.htm 73 de Mike, W4EF...............
Actually, it depends on whether or not you connect the shields together at both ends. If you don't connect the shields together at both ends, then current can be capacitively coupled from the center
Don't feel bad, Jim. I went to bed last night thinking that it was 1/2 the loss, but when my head hit the pillow I started to imagine two separate generators (one driving each coax with 1/2 the total
Hi Chuck, There should really be two power ratings for these isolator things. The first one should be the power handling for the normal differential transmission line mode. This test could be done w
Has anyone tried one of these in rocky soil? I thought about getting one to do my yard, but I have so many rocks in my soil, I figured it wouldn't last very long (one cubic foot of soil area in my ya
Yes, Jim, we used one of those "ditch witches" here at my QTH last year to lay drain pipe and my gas line. As you say a "very cool machine", but unfortunately, they are much too big for laying radial