[600MRG] "The Lowdown Amateur Radio Antenna for 630 Meters Model 630.PD"

Tue Jan 11 11:20:18 EST 2022

My 2 cents….

1) Today’s nanoVNAs are cheap ways to measure your antenna match right at the antenna w/o having to leave the TX running at low power while you go outside and tinker.

2) Over the Xmas holiday, I built a simple tandem match directional coupler that covers 2200 & 630m.  35dB directivity which delighted me.  I removed the HF coupler from a Daiwa 901HP meter and dropped in the new coupler. Result: A cross needle wattmeter for 2200 & 630m.

3) I want to modify the tandem match coupler into a scopematch too.  Should be as simple as a toggle switch on the coupler’s shielded box.  That would give the best of both worlds for me; a scopematch & a wattmeter all in one box.

So lots of options these days. But physics isn’t just a good idea, it’s The Law. :-)

-Brian, WA1ZMS
iPhone

> On Jan 11, 2022, at 10:39, Greg KF5N <greg.electricity at gmail.com> wrote:
> 
> 
> We didn't use a variometer on the Lowfer beacon I helped construct.  We made the highest Q possible series inductor, with the value being such that the inductor plus antenna resonated slightly above the transmit frequency.
> A small shunt variable capacitor was connected from the base of the antenna to ground.  So this small cap was used to "tweak" the system to resonance.  We had an ammeter to observe the peak as the capacitor was tuned.
> This worked well, as it was a beacon only and was operating on a fixed frequency.
> 
> But now with a real "band", a variometer seems like the way to go.  Remote tuning of the variometer would also be really great.
> 
> 73 Greg KF5N
> 
>> On Tue, Jan 11, 2022 at 10:17 AM Les Rayburn <les at highnoonfilm.com> wrote:
>> In the “olden days” of Lower (160-190 kHz) operations, we used RF current meters to adjust the taps and position of variometers on our TX verticals. Taps on the loading coil were used as a “broad” matches, and then you adjust the variometer for fine-tuning until you achieve peak RF current in the antenna. Before antenna analyzers this was the preferred method—and it still works great. 
>> 
>> LItz wire allowed for very high Q loading coils and minimal losses. 
>> 
>> Fortunately, physics doesn’t change much over the decades. It still works great today. 
>> 
>> 73,
>> 
>> Les Rayburn, N1LF
>> les at highnoonfilm.com
>> 121 Mayfair Park
>> Maylene, AL 35114
>> EM63nf
>> 
>> NRC & IRCA Courtesy Program Committee Chairman
>> Member WTFDA, MWC
>> 
>> Perseus SDR, Elad FDM-S2 SDR, AirSpy + Discovery, SDRPlay RSP-2 Pro, Sony XDR-F1HD [XDR Guy Modified], Dennon TU-1500RD, Sangean HDT-1X, Ray Dees RDS Decoders, Korner 9.2 Antenna, FM-6 Antenna, Kitz Technologies KT-501 Pre-amps, Quantum Phaser, Wellbrook ALA1530 Loop, Wellbrook Flag, Clifton Labs Active Whip. 
>> 
>> “Nothing but blues and Elvis, and somebody else’s favorite song…” 
>> 
>>> On Jan 11, 2022, at 8:33 AM, John Langridge <kb5njd at gmail.com> wrote:
>>> 
>>> I'm a big fan of the bucket variometer and if you take the time to
>>> wind it with taps every other turn minimum, you can resonant a 30 foot
>>> capacitively top loaded vertical in about 2 minutes just by checking
>>> each tap and watching what X is doing with your on your analyzer.  No
>>> calculations required to do that.
>>> 
>>> Then is just a matter or matching to the feed line and there are a
>>> bunch of options there and minimal math required.
>>> 
>>> John Molnar, WA3ETD, wrote a great article for CQ a few years ago that
>>> is more of less on his website with details for how he winds buckets:
>>> https://wg2xka.wordpress.com/the-variometer/
>>> 
>>> So there are easy options for resonating and matching existing
>>> vertical antennas on 472 for someone willing to put in a little elbow
>>> grease.
>>> 
>>> 73!
>>> 
>>> John..
>>> 
>>> 
>>> 
>>> 
>>>> On 1/11/22, Dwight Blevins via 600MRG <600mrg at mailman.qth.net> 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'sKW7TColorado
>>>> 
>>>>    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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