[600MRG] "The Lowdown Amateur Radio Antenna for 630 Meters Model 630.PD"
Brian Pease
bpease2 at myfairpoint.net
Tue Jan 11 14:02:24 EST 2022
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
> <greg.electricity at gmail.com> 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 <blethn at yahoo.com> 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
> <greg.electricity at gmail.com> 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 <kb5njd at gmail.com>
> 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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