Category: Buddipole

  • Buddipole vertical for 80m

    I spent the pleasant sunny part of the final day of autumn testing a vertical antenna for 80 metres using Buddipole parts for home.

    The back garden space here is barely 4 metres by 4 metres and for the moment the chimney is out of reach. While I have dreams of a magnetic loop for 80m, the vertical is more in reach now.

    Plan for 80m vertical made from Buddipole components

    I installed a counterpoise wire a few feet shy of 66 feet length hidden on a timber fence that runs down the side of the property. The idea is to connect a short fly lead to connect the hidden counterpoise when the antenna is deployed and then disconnect when it’s all packed away. Buddipole components don’t lend themselves to permanent installations. The counterpoise doesn’t follow the recommended dog leg arrangement and is higher off the ground than the 2 feet suggested.

    The purpose yesterday was to establish how speedily the antenna could be assembled and adjusted for a frequency of interest such as a net.

    Here’s a list of the items used along with the counterpoise:

    9′ telescopic whip
    2 x 22 inch antenna arms
    low band coil + clip
    VersaTee
    Buddipole short mast
    Buddipole tripod
    Balun

    I was surprised how easily it all went together. The adjustment wasn’t as fiddly as I expected such a short antenna for this band would be, and it appeared to give a usable bandwidth.

    The Buddipole Low Band coil showing the coil tap for 80m

    Assembly was straightforward. Set up the tripod and mast with only bottom two sections telescoped out. Attach the Versatee horizontally to the top of the mast. Connect the Low Band coil. Leave the red fly lead loose for the moment. Attach two 22 inch antenna arms to a long whip antenna fully extended. Then carefully attach that assembly to the top of the Versatee. I also connected a 1:1 balun between the Versatee and the iP30 SWR Analyser.

    The next step is to simply drag the fly lead across the coil turns to identify the best spot to tap the coil. Background noise level rises as you get in the zone. I used the iP30 SWR analyser to narrow it down to a spot 16 turns up from the base of the coil.

    This means I was shorting out the bottom 16 turns of the coil. The adjustment is too coarse on a turn by turn basis. You appreciate the value of being able to tap at 1/8 of a turn increments. (The coil is on an octagonal former.)

    It took me a few measurements to realise that as I progressed left (from my point of view) I was decreasing the amount shorted out and hence increasing the loading inductance and so lowering the resonant frequency. It’s actually more confusing reading that sentence than understanding it in practice!

    My target frequency was 3535kHz and this is a chart of the SWR readings I had when the coil tap was set at what I calculate to be 15 3/4 turns up from the base of the coil.

    frequencySWRfrequencySWR
    35051.8:135501.1
    35101.635551.1
    35151.435601.1
    35201.335651.2
    35251.235701.3
    35301.135751.4
    35351.035801.5
    35401.035851.6
    35451.135901.8
    The magic spot for my 80m vertical

    The 1.0:1 bandwidth was 10 kHz while at 1.5:1 it was in excess of 65 kHz.

    From readings at the other possible coil tap points my guess is that at this frequency range each face of the coil moves the resonant frequency by about 4 kHz. One thing to be aware of with the Buddipole hardware is not to accidentally short out adjacent turns of the coil with the coil clip. It’s hard to do but I managed and it will throw your readings.

    Next step of course is to make some contacts or at least activate the antenna on WSPR or JT65 to get an idea of whether the signal gets over the fence.

    From checking the chart on page 146 of the ‘Buddipole in the Field’ book by B. Scott Andersen, NE1RD, I estimate that my shorting tap at about 16 turns from the base means I’m using about 39-40 uH of loading to achieve resonance at 80m. So that’s a starting point if I wanted to build a more permanent and cheaper vertical installation.

  • Guide to A123 battery packs

    Charles Preston, a member of the Buddipole User Group email reflector has just posted links to two clear and useful guides to using the A123 Battery Packs available from Buddipole. While the Buddipole site links to documents about the batteries there’s very little practical information available about how to nurture these batteries. Similarly the Cellpro Multi4 charger documentation is more geared to the primary market – radio controlled airplane enthusiasts – so it’s great to see advice directly relevant to our intended use.

    The Revolectrix CellPRO Multi4 charger

    The first document is a Guide for Buddipole A123 Battery Packs and it explains how to maintain them and likely operating times for popular transceivers. The core of the document is how to charge the A123 Packs using the Multi4 charger (also available from the Buddipole site). There’s also mention of how to approach charging the Battery Packs with a solar panel and mention of the Genasun GV-4 Li 14.2 V MPPT controller. BatterySpace.com also sell a version of this charger designed for LiFePO4 batteries. Prices between US$110-119.

    It’s great to have all of this information available.

    The second document is Charging a Buddipole 4S2P or 4S4P A123 battery pack with a Cellpro 10s charger and focusses on the larger charger.

    Three cheers for Charles Preston!

  • ‘Buddipole in the Field’ by Scott NE1RD

    This is a great US$15 value! Only downside I can see so far is that after reading it you come out with a new wishlist of Buddipole accessories such as the 9.5ft whips, the shockcord mast, the longest shockcord whip and other bits and pieces.

    ‘Buddipole in the Field’ by Scott Anderson NE1RD

    Scott is great at explaining the most efficient ways to use the Buddipole system. Along the way you learn a lot about the behaviour of small HF antennas at low heights and this informs the configurations most likely to succeed in QSOs.

    While some of the info may already be available via the files on the BUG list site, the book pulls it all together and presents it so you have a clear idea of how it’s likely to perform. Some of the 10/12m beams and the VHF beams look very interesting. And further reason to hit the Buddipole accessories page which is another place you can order the book. It’s also available as a free download – in added colour – from the BUG Yahoo group page but if you’re like me you’ll find the printed book a useful companion.

    Scott is also active on the BUG fielding queries about the book and the Buddipole system. He brings a time-saving degree of order and logic to using the Buddipole. And the book is very practical. The info he presents helps you decide whether to deploy the Buddipole or try a dipole high in a tree – assuming the location offers you that choice. There’s a wealth of information about how best to use the Buddipole and the Buddistick as verticals. And no surprises here – more metal and fewer turns of coil loading needed, yield a bigger useable bandwidth.

    Now I’m hunting for some basic info about how best to use my new MFJ-269 Antenna Analyser with the Buddipole. Youtube, here I come!

  • Digging out useful info on gear

    Spent a bit of time visiting WW2PT’s site and reading the thread of messages tagged with ‘K3’. It’s great when you discover someone who has followed a similar path to the one you’re on and can write about with a combo of wisdom and wit.

    A key post is this one ‘Concerning computers about getting his K3 to talk with his MacBook Pro.

    This has to be the great difference to doing ham radio now compared to when I first got the bug back in the 1960s and 70s. The sheer volume of experience and overwhelmingly good will that’s materialised on the net has created an always available knowledge bank that’s transformed the most enjoyable part of hamming for me at least – troubleshooting. Sure there’s nonsense out there but it’s not too hard to discern. And then there’s the user communities!

    Elecraft’s trail-friendly KX1

    I bought the KX1 and K3 partly due to the solid community of users on the main reflector, lead in the best way by gurus like Don W3FPR who are so generous with their experience and don’t hesitate to share it, as well as the active involvement of Elecraft principals, Eric WA6HHQ & Wayne N6KR and others. Other purchases are informed as much as possible by getting a taste of the user community – aside for the occasional eBay impulse of course. Buddipole’s BUG has a similar shared spirit. It’s probably no accident that both lists are well moderated.

    As an example of what I’m talking about here’s an excerpt from Don’s reply to a recent query about whether or not to build the 80/30m option kit as part of the initial build of the KX1 or to do it later:

    “…there are pieces of the KXB3080 that can be installed during the initial build so you do not have to remove any more than 2 toroids. At one time, I created a “cheat-sheet” telling a couple of builders how to do it – I can try to find that email if you would like to try. I would only recommend doing that to an expert and confident builder. OTOH, an expert and confident builder would have no problem removing components from the PC board without damaging the board or burning the relay cases either.
    The KXB3080 is difficult to install because of the small space available in the KX1, and the instructions must be followed exactly, particularly the LPF board – if not done exactly like the instructions, it will interfere with the tuner.”

    Maybe this impresses me so much because I never was lucky enough to have an Elmer when I started out!

  • Buddipole set up videos

    I’ve only just discovered the set of video tutorials on YouTube featuring Chris W6HFP of Buddipole. They’re clear and well shot and edited, I suspect by Steve WG0AT. And they’ve been online for over a year!

    In this one Chris explains setting up a Buddipole Versatee Vertical.