Tuesday, March 17, 2009

Making the Connection

In the aftermath of the very fun ARRL VHF-UHF 2009 Sweepstakes, I am in the process of trying to upgrade my VHF-UHF capabilities. I've got a number of antenna projects planned—yagis, halos, all the good stuff—and, of course, putting more antennas in the air means that you've got to run feedline and make a connection to your rig.

In the past, I would have rather blindly figured that, since they put an SO-239 connector on the back of my rig (even for 2 meter and 70 cm connections) it must be just fine to use that for VHF-UHF stuff. Well, I'm finding out that that is an incredibly naive view.

Many of you may already know this, but the PL-259/SO-239 combination does not maintain a constant impedance as the frequency increases. So down in the HF range, you're probably fine. But as the frequency increases into the VHF and certainly in the UHF range, the connector itself can start giving you an impedance mismatch and the mounting signal losses that go with such mismatches. N connectors maintain a constant impedence at much higher frequencies, hence their usefulness in VHF and especially UHF and microwave applications.

Here's what Chris, KF9OP my microwave guru has to say about the matter:

When I think PL259, I think vacuum tubes, the Ed Sullivan show and the 1950's.

Then there's the post-hippie 1970's BNC option for less than 50 watts and less than 250 MHz. However, BNC was only designed for less than 500 MHz, and its main benefit is ease of connection. If this isn't of value, then I would only use it because of cost/availability.

The 1980's man, uses N for more than 50 watts, SMA for less than 50 watts.

The 1990's man doesn't use connectors, since the 1 dB per connector hit is too great. He solders directly to the PCB ;)

The millennial man doesn't use coax at all! He integrates his radio into his antenna and runs his power/data up the tower. ;)
Now Chris is way out of whack with his estimate of 1 dB per connector; a properly installed connector, of the correct type for the frequency used should be more like 0.1 dB. But that last point is something that Chris and I have discussed a lot. Especially as you go up, up, up in frequency it makes less and less sense to spend big $$$ to try and corral that RF as it goes through a feedline. If you put the transmitter at the antenna you save all that expense and path loss. But since that's not always practical, one does sometimes need to run feedline.

So, back to connectors, there was a good article on the installation of N connectors last year in QST magazine, "Those Type N Coax Connectors," in the April 2008 issue. Unfortunately, it's not on-line yet. But there is a diagram on this here. And there's an interesting exchange about the relative merits of the N connectors in ham radio applications over on EHam.net.

73 DE W9HQ

Wednesday, March 11, 2009

In Honor of Richard David (SK), the Original W9HQ

When I upgraded to an Extra class license and changed my call sign to W9HQ, I wondered about the man who had held this call sign before me. I did some initial searching back then, but came up empty on any specifics. Then the pressing details of life pushed that search out of the way. Early this year, I began searching again in order to put some information about him on this blog. Alas, I found the news that Mr. Davis had died just a few days before. I had missed the opportunity to correspond with him.

I believe that it is crucial to remember those radio amateurs who have gone before us. I am honored to have the call sign W9HQ and I want to make sure that I pay proper tribute to the man who held it before me. So far I have only been able to secure the published obituary and a beautiful tribute to Mr. Davis from a woman who stayed with that family as a foreign exchange student. He sounds like a wonderful person. I will be adding more information about his professional life and his ham radio activities as I am able to learn about them.

I would also like to ask all to pray for the repose of his soul.

Requiem aeternam dona ei, Domine, et lux perpetua luceat ei. Requiescat in pace. Anima eius et animae omnium fidelium defunctorum per misericordiam Dei requiescant in pace.

(Eternal rest grant him, O Lord, and perpetual light shine upon him. May he rest in peace. May his soul and all the souls of the faithful departed, through the mercy of God, rest in peace.)

SOUTH BEND -- Richard A. "Dick" Davis, 93, of South Bend, died at 11:30 a.m. Tuesday (Jan. 13, 2009) in The Sunset House of Mishawaka.

He was born Sept. 27, 1915, in LaPorte to Arthur S. and Louise (Wendt) Davis. On April 8, 1938, he married Marie E. Spromberg in South Bend.

She survives in Mishawaka along with two daughters, Kathryn L. (Gary) Wilson of Markle and Liese M. (Tom) Kreiser of Elkhart; one son, Dr. Timothy E. (Sandy) Davis of Elkhart; one adopted daughter, Gilly Simpson of Tunbridge Wells, Kent, England; eight grandchildren; and six great-grandchildren.

One brother, William Davis, and one granddaughter, Megan Wilson, preceded him in death.

Mr. Davis was a 1933 graduate of Central High School, South Bend. He began working at Bendix Corp. as a mail clerk and delivered the mail around the plant on roller skates. He retired in 1979 as supervisor of the aerospace division after more than 40 years of service. He had been active in the Boy Scouts, attaining the rank of Eagle Scout.

He was a longtime ham radio operator with the call signal W9HQ, and a member of Community Congregational Church of South Bend, Bendix Retirees Club and the Izaak Walton League. Mr. Davis, aka the "Watchdog of Juday Creek," fought off developers and pollution sources to preserve the creek, one of Indiana's last naturally spring-fed waterways. He designed and built his own home and cabinets, built dollhouse furniture for his daughters and volunteered at the Clay Township branch of the South Bend Public Library after his retirement, where he devised a method of repairing the bindings of old books that was adopted by other area libraries.