Hi all!
Built a 2x10 CP UHF antenna. Started with an Arrow 437X14. Two 7 element antennas on the same boom.
Added three sets of elements. Have been using this as a linear antenna in my satellite rig. It's been performing reliably for three years, including all DX trips
This is one of those projects that took a lot of learning, mostly how to use the analyzer and become good at SMA connectors.
Pic of the antenna here:
https://www.flickr.com/photos/n3ykf/44365875084/in/dateposted/
The next three photos are of the scans made at the end of the project, verifying CP, +/- 90 degrees. Note that the offset from the adapters has to be figured in. 18.3 degrees.
Using three 9V rechargables in series to make the +V to drive the relays. RG-142b/u and SMA male connectors both from ebay.
Got out to play with it a few days ago. The CP rig doesn't appear to add much to the received signal where there is no obstruction. It does make a noticeable difference toward the horizon where trees come into play.
While measuring parts, I found that the little 26VDC SMA relays measured out NC and NO to 231 and 231.8 deg respectively. The actual path: 4.5cm. HUH?
Managed to damage one of the relays. Bypassed the center pin crushing the female contact in the relay. So I took it apart. Nothing inside to justify an unusual measurement.
Pics here:
https://www.flickr.com/photos/n3ykf/44604433654/in/dateposted/
The SMA jumper that was made using 90's and adapters to connect NC->NC measured out to 281.3 degrees. Path measurement: 9.5cm. Another surprise.
Doing the math, the relays appear to have a velocity factor of .1(back of the envelope math). Is this for real? A surprise considering that I've never seen anything with that low of a parameter.
Catch you on the birds
Norm n3ykf