BTW there is an excellent and active Butternut group on Yahoo.
https://groups.yahoo.com/neo/groups/Butternut-antennas/info
Al
AB2ZY
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Steve
Bookout
Sent: Wednesday, September 14, 2016 8:52 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] HF6V choke coil
Hello all,
This base coil provides the correct amount of inductance to tune the antenna
for a low SWR on 75/80. There is no 'magic bullet' to how much this would be.
It all depends on each installation.
I have one installed at a vacation property with about 100 radials. The
antenna was given to me and did not have this coil with it. I wound
10-12 close wound wraps of some #14 solid, insulated house wire. I hooked it
up and measured the SWR in the part of the band I would be operating. I
stretched the coil to lessen the inductance and the SWR decreased. I kept
stretching and measuring till I got a good match. My nice, tight coil is now
about 14 inches long and in a 270 degree arc.
Obviously, I had much more inductance to start with, than I needed. I probably
could replace it with 3-4 close wound turns and re-tune, but it's not worth the
effort. Ugly, but works fine.
Point is this shouldn't be 'rocket science'. Make a coil with plenty of
inductance and then tune it by stretching the coil. Any decent wire is fine.
BTW, if you have a good RF ground (radials) you will find the 2:1
bandwidth quite narrow. Mine is something like 16 KHz. Beware those
who say 'I only use ONE ground rod and I have a bandwidth of 200 KHz!'
Those antennas generally make good dummy loads, but YMMV.
73 de Steve, NR4M
On 9/14/2016 7:31:PM, Stephen Lee wrote:
> Greetings to all,
>
> For the Butternut HF coil, check DX Engineering's Butternut parts web
> page. There's a good picture of the coil. On that picture I count 17
> coil turns along the top. I'm holding an older Butternut coil in my
> hand here in the identical position and count 18 turns across the top
> of this coil. On mine, there are no crimped on wire terminals. The
> coil wire is simply stripped and looped at each end with both loops
> being solder coated.
>
> Holding the coil just like in the web picture and slipping a tape
> measure vertically in amongst the coils I measure exactly 1-1/2 inches
> across the outside to outside diameter of the coils. The coil wire
> itself has a transparent red coating just as the picture indicates.
> The overall diameter of the thinly insulated copper wire is 85
> thousandths of an inch and that includes the insulation.
>
> Coil length is variable. According to the manual, one simply spreads
> it apart to effect a very narrow window of bandwidth within the 75 to
> 80 meter band. That coil should only effect the 75/80 meter band so it
> is possible to dial-in the antenna for use with the other bands. I've
> operated my Butternut without the coil; simply avoid transmitting on
> 75/80 meters.
>
> The Butternut HF series of verticals shipped with a piece of 75 ohm
> coax to be used in series with the feedline. Was that included with
> your Butternut vertical, and if so, could you send the end-to-end
> measurement of that piece of coax please?
> Enjoy! Stephen Lee N7RV
>
> On 9/13/2016 7:09 AM, Frank Davis wrote:
>> I have an HF6V that is missing the coil at the base…the one that
>> bypasses the base to ground. Can some one send me the dimensions (
>> length and diameter) and number of turns in that coil so I can make
>> one. Thanks Frank VO1HP
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|