Tri-band Repeater Antenna Construction Underway...

I'm in the process of making arrangements to relocate my 147.39+ repeater, 224.80- repeater, and 442.400+ repeater to a top perch on my tower at home. After 30+ years experience with amateur radio repeaters, I decided I do not want a fiberglass antenna on my tower...only a metal DC grounded antenna. I decided to set about to design a triband antenna for tower top installation for these 3 repeaters, with the vertical mast robust enough to support the DC grounded antenna for my 10 meter repeater RX side. 

I've started with a batch of DB Products folded dipoles. These are easily modified for correct operation on 2m, 220, and 440. These will all be fed from a single run of hard line via a 3 band tri-plexer. I've successfully fed the 10m receive antenna, 2 meter repeater, and 440 repeater like this in the past. Here's a few pics of the parts I'm working with. I'll update with more blogs as the project progresses. You can keep up with it by looking in the RH column in the "Jump to Blogs of Specific Topics", and clicking on "Repeater-Antennas". 

The long antenna is a Hy-Gain CLR2 I am repairing / retuning to 29.520 mhz for the 10 meter repeater's receiver.  

 The Hy-Gain CLR2 is a DC grounded 5/8 wl CB antenna, and makes a great 10m antenna.

 

Here's a batch of the folded dipoles from DB Products that I am re-purposing  for this custom build. They typically run around 110 ohms, so I'll be building a phasing & impedance matching  harness for these, once tuned.

Load of parts, ready for cleaning and mods. I actually picked these up years ago and stored them away.

Dave WB4IUY

www.WB4IUY.net

Yaesu FL-2100Z Amplifier in the shack!

I've been playing with a new (to me) toy in the shack, recently. It's the Yaesu FL-2100Z HF amplifier. It's fairly rare, not nearly as easy to find as the FL-2100B. This version was more common in other countries, and has all of the WARC bands on the band switch and tuned inputs for them as well. It uses a pair of Cetron 572B tubes at about 2600VDC. Cetrons are the only 572B tubes that can be operated in a horizontal position, none of the other brands have supports on the grids to keep them from sagging into the plates when operated in this position. This is a sweet little amp, and runs around 500-600 watts output, depending on the band. This one was actually bought to serve as a "guinea pig" for a conversion project to the Russian GI7B tubes, but that's a story for another blog. Here's another pic of it, in operation with my old Yaesu FT-901. I love the looks of this lash-up!

Dave WB4IUY
www.WB4IUY.net

Signal Electric M100, sorta...

This is the best handling straight key I have in the shack. It's a Signal Electric M100, and was made somewhere around 1939-1941, as best as I can tell from markings and catalog info. This one is equipped with a leaf spring, instead of the typical coil spring, and I've not been able to find any of the Signal Electric "J-38" style keys like that...so I'm a bit baffled by that part. If it was converted by someone, they did a great job: the lever spring force feels perfect and is very easy on the wrist. 

I've not tried to clean it, other than to brush the dust off of it. It looks to be all solid brass (not brass plated steel, as it's non-magnetic), with a plated steel lever and flat top knob. 

Signal Electric M-100 with leaf spring...

Close up shot of the leaf spring setup...

This leaf spring arrangement is a mystery to me, but it works great!

You can faintly see the "SIGNAL ELECTRIC MFG CO. MENOMINEE, MICH" markings in base, under the "up" adjusting screw contact point.

Dave WB4IUY

www.WB4IUY.net

Storm Damage, 2/6/2020

I had a little storm damage to the tower mounted antennas on 2/6/2020, though only a small amount. My tower is 105' tall, and the yagi antennas are mounted on top of that. The lowest antenna is the 6el Force-12 HF yagi, the middle yagi is the Cushcraft a50-5S 5el 6 meter yagi, and the top yagi is a Cushcraft 13B2 2m SSB yagi. 

We have had a weird winter...warm and wet. This is normally the time of year where we have temps in the low teens and the largest snowfalls. This year, we've barely run the home heating system, with lots of days in the 50's, 60's, and even 70's...and lots of rain. On this day, the temps started off in the 70's, fell about 20 degrees, and tremendous winds blew through. Rain storms were reported at moving over 100 mph (!!) by the local weather station, and there was lots of wind damage. We had loads of tree limbs down, but the damage in the photo below is the only antenna damage I had. The Force-12 at 105' was twisted on the vertical mast, the 6m 5 element yagi had a little damage to the reflector, and the tower mounted dipoles for 80 & 160 had a limb hanging on them. That's all! I'll take that any day, compared to the storm damage in 2016 that took the tower down :-)

Dave WB4IUY
www.WB4IUY.net

Portable Radio for RENT!

Boy, have times changed! This was supposedly a profitable business, back in 1948. Check out this cover from Radio News, May 1948...

Dave WB4IUY
www.WB4IUY.net