The AV-640 is actually a 3/8 wave vertical. I measured it on all bands. That
is why the need for the balun. And I am not so sure that it is 4:1.
At 3/8 wave, the impedance is quite different from a 1/4 wave antenna. But,
it has a lower angle of radiation than a 1/4 wave.
I mounted mine at 7 ft above ground. I foud that height did not improve it's
performance. And, the HyGain manual clearly states that height has no
significant advantage. Just keep the tips of the counterpoise at a level
that does not poke someone's eyes out if they inadvertantly walk into it.
I use no guy wires and we have some pretty stiff winds here in Florida. It
just waggles around in the wind a bit. pretty robust antenna.
I am still curious how those shorting straps on the 30/40 meter coils work.
They appear to eb a short circuit on DC but I have no idea how they work at
RF.
Dan Schaaf
K3ZXL
"In the Beginning there was Spark Gap"
www.k3zxl.com
----- Original Message -----
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
To: "Tower and HF antenna construction topics." <towertalk@contesting.com>
Sent: Sunday, April 25, 2010 7:39 PM
Subject: Re: [TowerTalk] AV-640 (was GapChallenger ComparisonTesting
Studies)
> The AV640 is electronically simple, although a bit complex mechanically
> (lots of parts)
> Each band is independent of the others and there is no interaction
> between bands when setting the resonant frequencies. The matching
> network consists of a current balun wound on two toroid cores. This is
> followed by a 4:1 balun which is also wound on two cores and is used to
> "step up" the antennas low impedance of 12.5 ohms to 50 ohms. The
> elements are a bit longer than a 1/4 wave electrically and that
> reactance is tuned out by a fixed value "compensating" capacitor. SWR
> "for mine" is virtually 1:1 at resonance on all bands. It will also
> cover each band in it's entirety with the exception of 40 with a low
> (read useable) SWR. IIRC it'll cover about half of 40 at less than 2:1.
>
> Although advertised as self supporting, with mine mounted at 40' I have
> insulated guys at roughly the mid point.
> I cut a disk out of 1/4" Lexan using a hold saw and drilled 3 1/4" holes
> around the edge at 120 degree spacing. The center has a hole just large
> enough that it's a loose fit over the center radiator, so the guy
> connection is more of less floating.
>
> The system is broad banded compared to trap verticals and should be a
> better performer than trap verticals although I'd not expect the
> performance between any of the multi band verticals to be "blazingly"
> different.
>
> It is rated for the legal limit on SSB for 40 though 10 and 300 watts on
> six meters. The antenna is derated for other modes. I'm assuming the
> de-rating is due to heating of the toroid cores. I believe the early
> ones were rated for 200 watts on six. I've run 800 watts SSB on six for
> up to two hours with no problems
>
> I'm going to try 4 toroid cores in both the 4:1 and current balun and
> see if it will handle more power. It'll be #31 mix for the current
> balun, but I'm not sure which mix to use for the 4:1 voltage balun as
> it's a true transformer.
>
> I have no experience with the R7 and R8 but I'd expect them to be
> comparable to the AV640 and all to be much better than the trap, multi
> band verticals.
>
> 73
>
> Roger (K8RI)
>
> Dan Schaaf wrote:
>> I didn't get it to work on 160. !!!
>> But, if you notice, the frequency on the 17 meter band is 10 times the
>> frequency on 160 meters. A tuner can load it. but it is not wise to do
>> so.
>> Once I realized that I had the antenna switch in the wrong place, it was
>> too
>> late.
>> Likewise, a 17 meter vertical too close to a 160 meter vertical causes
>> SWR
>> fluctuations when the wind blows the antennas around.
>>
>> Dan Schaaf
>> K3ZXL
>> "In the Beginning there was Spark Gap"
>> www.k3zxl.com
>> ----- Original Message -----
>> From: "RICHARD SOLOMON" <w1ksz@q.com>
>> To: "TowerTalk" <towertalk@contesting.com>
>> Sent: Sunday, April 25, 2010 6:44 PM
>> Subject: Re: [TowerTalk] AV-640 (was Gap Challenger ComparisonTesting
>> Studies)
>>
>>
>>
>>> How did you get the AV-640 to work on 160 ??
>>>
>>> 73, Dick, W1KSZ
>>>
>>>
>>>> From: n7xy@clearwire.net
>>>> Date: Sun, 25 Apr 2010 15:40:58 -0700
>>>> To: towertalk@contesting.com
>>>> Subject: Re: [TowerTalk] AV-640 (was Gap Challenger Comparison Testing
>>>> Studies)
>>>>
>>>> I haven't had any insulator issues, but one of the 40 meter capacity
>>>> hat wires has a noticeable bend from putting it up single-handed.
>>>>
>>>> I have had better-than-expected results on 160 at 100 watts (> 150
>>>> QSOs at distances up to ~1500 miles). I wouldn't try running higher
>>>> power than that.
>>>>
>>>> Bob N7XY
>>>>
>>>> On Apr 25, 2010, at 3:13 PM, Roger (K8RI) wrote:
>>>>
>>>>
>>>>> Dan Schaaf wrote:
>>>>>
>>>>>> Right, My AV-640 has worked the world, literally. I could spend a
>>>>>> lot of
>>>>>> time telling stories .
>>>>>> On 12 meters, ragchewed with N2WB op at VP6DX on 12 meters between
>>>>>> band
>>>>>> opening. I was running 100 watts SSB
>>>>>> Likewise on 30 and 40 I have 266 and 269 countries logged .
>>>>>> You just have to keep an eye on the 17 meter stub insulator at the
>>>>>> top of
>>>>>> the stub. The insulator can burn and short the stub to the main
>>>>>> radiator. I
>>>>>> think it happened here once due to accidentally loading the
>>>>>> antenna on 160
>>>>>> meters. That point on the stub became a high voltage point and the
>>>>>> insulator
>>>>>> was wet from morning dew.
>>>>>> Replaced the insulator and all was well again.
>>>>>>
>>>>>>
>>>>> I've had a couple of the insulators break. (hit a tree on the way
>>>>> up and
>>>>> down - Hired tree trimming crew, Strong wind blew small limb from
>>>>> neighbor's lot and hit antenna) I made new ones from scrap 1/4" Lexan.
>>>>> Just use one of the old ones for a template. I also found that if the
>>>>> material from the broken one is sound, they can be "super glued" back
>>>>> together and last quite well.
>>>>>
>>>>> Compared to sloping half wave dipole it does quite surprisingly
>>>>> well on 40.
>>>>> Not meant for heavy duty QRO.
>>>>>
>>>>> 73
>>>>>
>>>>> Roger (K8RI)
>>>>>
>>>>>
>>>>>> Dan Schaaf
>>>>>> K3ZXL
>>>>>> "In the Beginning there was Spark Gap"
>>>>>> www.k3zxl.com
>>>>>> ----- Original Message -----
>>>>>> From: "Bob Nielsen" <n7xy@clearwire.net>
>>>>>> To: "Tower and HF antenna construction topics."
>>>>>> <towertalk@contesting.com>
>>>>>> Sent: Sunday, April 25, 2010 4:40 PM
>>>>>> Subject: Re: [TowerTalk] Gap Challenger Comparison Testing Studies
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Try <http://www.championradio.com/HF-VERTICAL-PERFORMANCE-TEST-
>>>>>>> METHODS-RESULTS.3>.
>>>>>>>
>>>>>>> The AV-640 was not included in the comparison, however it is quite
>>>>>>> similar to the R8. Based on the R8 data I decided to purchase a
>>>>>>> AV-640 and have not been disappointed.
>>>>>>>
>>>>>>> Bob, N7XY
>>>>>>>
>>>>>>> On Apr 25, 2010, at 12:19 PM, Dan Schaaf wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> This link only takes me to the home page. (http://
>>>>>>>> www.championradio.com) I
>>>>>>>> want to know where is the related comparison?
>>>>>>>> I want to see how my AV-640 stacks up against the others.
>>>>>>>>
>>>>>>>> Dan Schaaf
>>>>>>>> K3ZXL
>>>>>>>> "In the Beginning there was Spark Gap"
>>>>>>>> www.k3zxl.com
>>>>>>>> ----- Original Message -----
>>>>>>>> From: <K7LXC@aol.com>
>>>>>>>> To: <towertalk@contesting.com>; <ka2qwc@verizon.net>
>>>>>>>> Sent: Sunday, April 25, 2010 2:16 PM
>>>>>>>> Subject: Re: [TowerTalk] Gap Challenger Comparison Testing Studies
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> In a message dated 4/25/2010 8:38:22 A.M. Pacific Daylight Time,
>>>>>>>>> towertalk-request@contesting.com writes:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> Has anyone done a study? evaluating? the GAP CHallenger DX,?
>>>>>>>>>> against
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> other verticals?
>>>>>>>>> Butternuts, Hygain, CrushCraft, Steppir rtc..
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> If so I would like to see the results as the peratin to
>>>>>>>>>> performance. I
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> am not intersted in anecdotal evidence just fact. If any one has
>>>>>>>>> performed
>>>>>>>>> testing I would like to hear from you. If there is enough?
>>>>>>>>> response I
>>>>>>>>> will
>>>>>>>>> summarize and post the results.
>>>>>>>>>
>>>>>>>>> Yessireebob. To quote from _www.championradio.com_
>>>>>>>>> (http://www.championradio.com) , "Now you can read an unbiased
>>>>>>>>> report on
>>>>>>>>> how they really
>>>>>>>>> performed. Antennas tested include the Cushcraft R8, Butternut
>>>>>>>>> HF6V, MFJ
>>>>>>>>> 1798,
>>>>>>>>> Force 12 ZR-3 and V-3, Diamond CP-6, Hustler 6BTV and Gap Titan.
>>>>>>>>> It's 64
>>>>>>>>> pages of protocol, data sets and summaries. Presented at the
>>>>>>>>> Dayton
>>>>>>>>> Hamvention."
>>>>>>>>>
>>>>>>>>> Not exactly the Challenger but full of lots of actual data and
>>>>>>>>> observations. It's the only on-the-air HF vertical comparison
>>>>>>>>> report in
>>>>>>>>> the world.
>>>>>>>>>
>>>>>>>>> Cheers,
>>>>>>>>> Steve K7LXC
>>>>>>>>> Champion Radio Products
>>>>>>>>> Cell: 206-890-4188
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> 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
>>>>>>>
>>>>>>>
>>>>>> _______________________________________________
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> 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
>>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> 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
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|