Topband: 160M Rhombics

[Carl]

> Anybody on this list have a Rhombic for 160M?
>
> W1AW used to use one for bulletins and code practice on 160M but I think 
> it came down years ago (1989?)


They come in here literally against the pin which makes me wonder about the 
power used. Even the New England QRO++ Dxers and contesters arent that 
strong unless real close.


>
> I seem to recall pics in CQ of a big California desert DX'er who had what 
> was essentially a radial array of rhombics for maybe 160M or 80M.
> Tim N3QE
>


That was likely Don Wallace, W6AM overlooking the Pacific from a bluff in 
Rancho Pales Verdes.
Google his antenna farm and then do a Google Earth of the place today!

Carl
KM1H



> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Grant 
> Saviers
> Sent: Friday, July 26, 2013 11:03 AM
> To: ZR
> Cc: Gary at ka1j.com; topband at contesting.com
> Subject: Re: Topband: Topband Inv-L Joy
>
> Posted on towertalk yesterday was the link to the free download of the
> 1952 text Radio Antenna Engineering
> http://www.lulu.com/us/en/shop/edmund-laport/radio-antenna-engineering/ebook/product-17560294.html
>
>
> Some fascinating stuff since much of the focus is high power
> broadcasting LF/HF and point to point reliable RF links with high gain
> HF wire antennas.  (many pictures of amazing arrays).  A quick peruse
> found in a later chapter how to build high power non-inductive
> terminations for rhombics etc.  Make an open wire feeder of the needed Z
> from iron or stainless wire and as long as the db's you wish to absorb
> and with wire heavy enough to handle the current.  Clever stuff,
> invented when HF was a primary long distance communications technology.
> The formulas are there for resistivity and ferromagnetic losses.
>
> Of course some of the content is now pretty irrelevant since we have
> cheap great coax, ferrite, and NEC software and a billion times the
> worlds 1952 total computing power on every desktop.
>
> Grant KZ1W
>
>
> On 7/25/2013 8:17 AM, ZR wrote:
>> On a side note WD-1A conductors are a copper/cadmium alloy; whatever
>> that means in RF resistance. Fine for a Beverage but what is the loss?
>>
>> Carl
>> KM1H
>>
>> ----- Original Message ----- From: "Gary Smith" <Gary at ka1j.com>
>> To: <topband at contesting.com>
>> Sent: Thursday, July 25, 2013 1:22 AM
>> Subject: Re: Topband: Topband Inv-L Joy
>>
>>
>>> Had a more difficult time getting the antenna up there this time. The
>>> first spud snapped away from the fishing line & in the dense thicket
>>> I was unable to find where it landed. Had to make another & the
>>> mosquitos were so thick they posted a LUAU sign on my forehead.
>>>
>>> Till I get something better I retrieved my WD-1A military field phone
>>> wire that was left out in the marsh as my old beverage wire. and
>>> after a comedy of errors I finally got the antenna up.
>>>
>>> I was earlier getting a SWR of 1.1 on 160 before and now am getting
>>> 1.1 on 1.74365 MHZ
>>>
>>> 1.74365mhz
>>> R=51 X= 6,7,8
>>> swr 1.1
>>>
>>> At the desired frequency to match the antenna I've aimed for 1.8MHZ
>>> here's the information I was able to get at my desired frequency:
>>> 1.8025 mhZ
>>> Coax loss 6.3db
>>> C=4193  XC=21
>>> L=1.970  X1=21
>>> r=41 x=21 swr 1.6
>>>
>>> So this is what the antenna is giving me at this moment. I need to
>>> get back down and add the broken wire to the radial bed and I should
>>> also trim some length to bring my values to 1.1 at 1.025MHz.
>>>
>>> Given the info above from the MFJ 259B any idea how much I might
>>> nibble off and more, is there anything in this info that tells me I
>>> should look to do anything differently?
>>>
>>> Hopefully the coax loss will be mitigated by a friend bringing me
>>> 350' of hardline. Can't wait!
>>>
>>> Thanks,
>>>
>>> Gary
>>> KA1J
>>> _________________
>>> Topband Reflector
>>>
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>>
>> _________________
>> Topband Reflector
>>
>
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