From: [email protected] <[email protected]> on behalf of Brian Pease <[email protected]>
Sent: Tuesday, January 11, 2022 11:02 AM
To: [email protected] <[email protected]>
Subject: Re: [600MRG] "The Lowdown Amateur Radio Antenna for 630 Meters Model 630.PD"

My 50 ft high inverted L on 630m has a ~300 ft horizontal wire, so my tuning inductor is small. It has a shunt vacuum capacitor driven by a cheap gearhead DC motor from mpja.com, without a turns readout display. I use a large binocular core ferrite as a transformer to reach 50 Ohms. I have an analog SWR/power meter in the shack that a ham was selling on Ebay designed for 630m that also works well on 160, 80, etc. I am always below 2 Watts reflected for 100 Watts in. It is -4 F outside at the moment and I am not about to make a 600 foot roundtrip through the snow to the tower to tweak something! I used NEC4 simulations then used an AIM/UHF analyzer to do the initial setup.

On 1/11/2022 9:58 AM, Dwight Blevins via 600MRG wrote:

Greg,

At first I was just using my bucket coil, attached at the base of my Hustler 5 band HF trap vertical. My perception is that the trap coils, especially the big 40m thing at the top, which serves both as a trap and loading coil for 80--that all these coils were just more or less dummy loads, eating up a lot of RF. So I decide that I wanted a straight up vertical, no traps, but with the top hat wires coming down for support.

Long story short, I bought one of these 19' UK hf verticals, took off the balun at the base and used that antenna instead, along with a cheap 60" whip which I mounted on top of all else. In retrospect I realized that I could have accomplished the same thing with some telescoping PVC and a big heavy gauge wire (maybe 8 to 10 gauge) running up the pvc for the vertical part of the radiator. Some of the green military telescoping fiber glass poles would do the same thing. I see them around on eBay and they are probably better than HomeDepot PVC.

The tricky part is that you've got to put plenty of taps on that bucket wire so that you can find the right impedance match, both for the feed point and a tap at the top to resonate the bucket with the vertical radiator. The variometer adjustment with the bucket is super if you can get the mechanics worked out so that it's easy to adjust and stays put where you want it. I finally gave up on that because I kept having to go out to the bucket and readjust all the time. So I finally opted for the multi-tap wire bucket and that remains pretty stable.

Hope all this helps. I'm old school so have to stick with 1950's technology :)

KW7T

On Tuesday, January 11, 2022, 07:40:58 AM MST, Greg KF5N <[email protected]> wrote:

Hi Dwight, thanks for the tip! What do you consider to be a "cheap 25' vertical"?
I was looking at sectional aluminum flag poles and I was wondering how well that would work.

73 Greg KF5N

On Tue, Jan 11, 2022 at 9:01 AM Dwight Blevins <[email protected]> wrote:

Greg,

You asked about "something equivalent." There definitely is and it will cost you maybe $125.00 max (if that). The equivalent is a 5 gallon plastic bucket, a cheap 25' aluminum vertical and a roll of solid core insulated wire (16 or 18 gauge). Add a 3-wire top hat to the vertical and ground mount the thing with the big bucket loading coil, feed point taped up from ground. I'm 75 years old and easily picked up the whole apparatus and had it up and tied off in less than an hour, once everything else was assembled.

It works great on receive and my little 5 watt one tube 630m exciter loads up with ease. I can copy KB5NJD Q5 most any time he is on the air, CW. All I have for a counterpoise is that the mounting mast goes in the ground maybe 40 inches and I have that tied off to a nearby chain link fence. Again, tip of the antenna is maybe 25' up. For the top section I bought a 60 inch whip which attaches to the top of the vertical where the top hat wires are connected. They go down at a 45 angle, tied off with insulators to stakes on the ground. So the 3 top hat sloper wires serve to support the slender vertical when the wind comes.

I don't know what the radiation resistance is, but the thing works great, low background noise, no BCI garbage, etc! I'm not saying don't buy the commercial antenna, but on my budget I have to make my own stuff, which is the fun part of the hobby :)

73's

KW7T

Colorado

On Tuesday, January 11, 2022, 06:38:03 AM MST, Greg KF5N <[email protected]> wrote:

I like the design as I could use it even in my relatively small back yard.

The availability of a turnkey antenna and other gear is good, but I'm not even sure there is that much easily available reference material if you want to build your own.
I recently ordered the 2022 ARRL Handbook, and found only one page on LF propagation. Did I miss something, or is there no other information on the ham LF allocations in the latest handbook?

Let's say I was a newbie interested in trying out 630 meters. Where would I go to find construction details for an antenna equivalent to this commercial offering?
Long ago (1980s) I built and operated a Lowfer Beacon. There was the series of books by Ken Cornell, and a couple of enthusiast periodicals on Lowfer and other LF topics.
Lots of antenna topics and construction articles in those publications.
Is there something equivalent to this today for 630 meters?

73 Greg KF5N

On Tue, Jan 11, 2022 at 8:03 AM John Langridge <[email protected]> wrote:

Good morning,

Jamie, N2VJ, reported this morning on SLACK that a US-based company is
producing a portable, turnkey 630-meter vertical antenna system.
Originally developed for BC medium wave AM as an emergency continuity
system, this model has been modified for 472-479 kHz. You can see the
specs here: https://theradiosource.com/products/antenna-630pd.htm

Jamie indicated that the company is probably testing the market and
the price may be somewhere in the $890 USD range. While that may seem
pricey to some, there are a lot of people out there still waiting for
a turnkey option and engineering and materials are expensive these
days. Yes you can build this stuff for a LOT cheaper but there are a
lot of hams today that can't or won't so here is an option to fill the
void.

Have a look and show some interest as doing so often drives product
development and innovation.

Jamie explicitly noted that he is not endorsing this product and he
has no financial interest.

73,

John KB5NJD
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