KB9VBR J-Pole Antennas

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Your Questions Answered- February 2020

Posted: 19 Feb 2020 08:45 AM PST
https://www.jpole-antenna.com/2020/0...february-2020/

It’s February so we’re half way through winter. The days are getting longer
and the sun warmer. In no time I’ll be pulling the trailer out of the
garage and planning some outdoor adventures. In the meantime I’ll have to
contend with indoor operations. Please stay tuned to the end for an update
on what will be happening in the coming week. But first‚ the questions.


I’ve got a few miscellaneous‚ but quite interesting‚ questions here and
then we’ll move into a more in depth talk on my recent video on if snow
affects your vertical antenna performance.
Gill asks the following question about cross band repeater operation:

Will using a repeater that is linked to say 20 other repeaters through out
the state be an issue?

No‚ it shouldnt be an issue. You can cross band into a linked repeater
system just like any other repeater. I’ve crossbanded on linked repeater
systems with fine results. Just remember to wait about a second when you
key up before speaking so that the crossband and the links have time to
engage. But on a side note: not all repeater owners may like or appreciate
cross band operation on their system. Sometimes the extra noise of the
squelch tail that common with a cross band can get compounded through a
linked system‚ so if you plan to use a cross band on a repeater on regular
basis‚ you should first ask permission of the repeater owner or trustee.
Another Gil asked a question about using a DMR Hotspot

Should I leave my DVMEGA Hotspot powered up all the time? (Most of the time
it is not Used)

I leave mine on all the time‚ as the energy consumption is quite low. If
you dont want the hotspot to be transmitting when you arent listening to
it‚ you can disconnect from the active talk group. This is done by
transmitting a briefly to talkgroup code 4000. To do so‚ program talk group
4000 into the contact list in your radio and then briefly key up on that
talkgroup to send the code to the hotspot. It will disconnect from the
active talkgroup.
Sage just got his Technician License and is asking about his Certificate of
Successfully Completed Exam

Can you explain the meaning of the statement on the CSCE Technician
paperworkCREDIT FOR ELEMENTS PASSED VALID FOR 365 DAYS.Â* Isnt the license
good for 10 years?Â* Or is there something that needs to be done in that one
year window?

That phrase is a holdover from the days when passing a morse code test was
required for General and Extra class licenses. Back then you could have
passed your Element 3 General written test yet failed the Element 1 code
test. Your certificate for successfully completed exam (CSCE) would give
you a 365 day window to pass the code test and complete the upgrade.
Nowadays since code isnt required‚ the exam credit is a moot point as you
either pass and upgrade or fail and not.
Moving on; I received a lot of great advice and information pertaining to
my recent video on if snow can affect the ground radial performance of a
vertical antenna system. If you remember my results from my initial video
the testing was inconclusive- so I asked the viewers if they had more
information and resources. The hive-mind responded and I thank everyone
that took the time to give me direction on where to look for published
information. I’ll follow up on a few questions but this isn’t the end of
the subject as I’m going to continue testing and researching for a more
definitive answer.
Starting out- Ross says:

I always enjoy your videos!!!! One question: With your wolf river antenna
system,Â* how many radials are you using and are they cut at specific
lengths for your operating frequencies?Â* Also, does the antenna benefit
from being grounded?

I’m not sure if I mentioned in the video on what I’m using for radials but
I have three ground radials each 32 feet in length. At this length they
tend to work best at the lower lengths but can be a bit finicky 20 meters
and above. I do the same thing when I use the antenna portable and will
roll up the radials to shorten them for a better match on the higher bands.
Unfortunately I cant do that when they get buried in snow and ice. For
radial length‚ a general rule is that if they are non-resonant on all the
frequencies you wish to work on‚ they will work acceptably on those
frequencies.
As for grounding‚ I dont really think additional grounding is necessary if
you are already using a ground radial network. I didnt ground the antenna;
although I suppose with it mounted on a fence post there would be a certain
amount of grounding. But its tenuous as the post is also painted.
We’ll talk more about grounding as Claude brings up the following point:

This Snow subject and radio waves is something I deal with more on Military
excercises. You lose transmitting and receiving strength.

First of all to do this test for the sake of this viewers question, an
antenna that is tested before a snow fallÂ* is grounded. Now try this same
test with the antenna not grounded into the earth. But sitting on the
snow.Â* Because snow is Distilled water it can not conduct electrical
current no matter if it is wet or dry snow. This is why we have such a
problem inÂ* snow without a ground plane.
My buddy Joe‚ who also happens to be an electrician says:

Should actually be worse for ground radiation. Thats why Wisconsin requires
two ground rods at a service. When the frost runs deep the first 4 feet of
ground wont conduct like thawed ground. He also reminded me that RF and 60
hz electricity act similarly.

So if you want to take advantage of ground wave propagation‚ and ground
wave would be crucial for medium frequency propagation like 160 meters‚
then a suitable ground is paramount for cold weather environments.
In fact‚ another Joe reminds us that AM broadcast band signal ground wave
signal strength always appears stronger in the winter months vs. the warmer
summer months. If you have an AM broadcast band receiver with a signal
strength meter you can note either bar or number readings from summer and
then in winter. In every case, the reading are always higher in the winter
especially with snow and cold weather. Its always been my assumption that
medium wave ground conductivity (including 160 Mtrs) is better in the
winter. Since your doing your tests on 40 Mtrs, the effects on snow and
cold may be less noticeable.
Most of the research I found online was geared towards AM and medium
frequency operations and not so much the HF bands. But I think the reason
is that there is that the commercial operations on the AM band requires a
station that operates in a predictable manner.
Which brings me to another commend from Claude:

An excellent source of information isÂ* MCRF 3-403B Radio Operators Handbook
Refer to Chapter 6-6 which explains winter operations very well.

Thanks for pointing me to the resource. The Radio Operators Handbook from
the US Marine Corp has a wealth of information for the HF portable
operator. One thing I’ll point out is that it’s written in a very practical
manner so you won’t find much in regards to theoretical reasoning‚ but
still the manual writes about cold weather operation:
Because of permafrost and deep snow, it is difficult to establish good
electrical grounding in extremely cold areas. The conductivity of frozen
ground is often too low to provide good ground wave propagation. To improve
ground wave operation, use a counterpoise to offset the degrading effects
of poor electrical ground conductivity. Remember to install a counterpoise
high enough above the ground so that it will not be covered by snow.
I’ll put a link to this book in the video description below. Reading
through it‚ I think it will be an invaluable resource to the portable
operator.
And finishing up‚ JP mentions:

Hi Michael, would love to see a redo of these tests with bare (non-coated)
copper or aluminum wire to allow contact with rain/snow/ice etc.

I’m not done with this subject‚ so I’m going to continue testing and will
share my results along the way. I’ll repeat these tests with bare wire
radials. I have a bunch of aluminum electric fence wire that should work
well as a radial network. So I’ll see what kind of results I get. I also
plan to test and take readings on other bands: notably 20 and 80 meters in
addition to 40 meters. Finally I’ll also redo my tests in the spring after
the snow melts and the ground thaws but before the leaves sprout on the
trees. So youÂ* can expect a followup report later in the spring.
If you have any thing else I should do or try: leave it in the comments
below. I’d love to hear them
Before we close down this video I just want to share what’s coming up for
the month. I plan to have a followup on my video on APRS with the Yaesu
FT3DR. I received enough questions on that to fill up an entire video. Last
week I was volunteering at a sled dog race in Northern Wisconsin and I’ll
have a video on how that went. And I recently received a question about
power supplies so something on that will be coming too. If you have a
subject that you’d like to see‚ please leave it in the comments below and
I’ll add it to the list.