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OT: TADX on Band 2 FM this evening!  View Printable Version 
Tuesday, July 10 2018

IRCA

 

phasing units, then and now  View Printable Version 
Monday, July 09 2018

IRCA
Hi Mark,

That was an excellent overview of DX hobbyist use of phasers! You covered
the early history which I wasn't aware of, as I was mostly DXing on the
tropical bands when Gordon Nelson and others did their pioneering work.

There is one more phase (LoL) developing now--software based methods using
coherent dual tuners (or channels).â I'm sure you're aware of Afedri's AFE822x
SDR-Net device
<http://www.afedri-sdr.com/index.php/new-afe822x-sdr-net-dual-channel>. It
was introduced a couple of years ago, but unfortunately software has not
appeared to easily take advantage of phasing. If you jump through a lot of
hoops and complexities with LINRAD, you can catch a glimpse of the future
of software phasing, but it's nothing practical for a DXer's use in my
opinion.

Much more recently, SDRplay's RSPduo <https://www.sdrplay.com/rspduo/> was
introduced with its dual tuners. I have one myself, mainly for its future
possibilities. I'm hoping that the 14-bit structure and additional front
end filters will provide better basic performance than earlier RSP models
I've owned.I expect it to be neck-and-neck with the AirSpy HF+ SDRs in a
quiet DXpedition setting...maybe not so much in my suburban RF jungle.

SDRplay looks to be the most active of all the SDR software developers, and
they say they fully intend to offer phasing features in a future release of
SDRuno software. Their activity, enthusiasm, and customer support make me
think they are the group most likely to take software phasing out of the
laboratory and into the DXer's shack. If he has the time and inclination,
Simon Brown of SDR-Console software could implement RSPduo phasing too, but
he's *not* dropped any hints about this.

73,

Guy Atkins
Puyallup, WA

 

phasing units, then and now  View Printable Version 
Monday, July 09 2018

IRCA
Hello Guy,

You have raised an interesting question ref. using dual channel SDR for
phasing. These may in future afford an alternative to some expensive
commercial phasers. Also the SDR has the option of offering a fixed phase
over a very wide bandwidth. This could be useful for phasing two orthogonal
loops to provide omni-direction or with a loop + a resistance loaded
longwire for a wideband cardioid pattern.

However, like most other phasing schemes the SDR cannot provide a null over
a wide bandwidth when used say with similar antenna pairs. This can only be
done with a special Phased array controller when the two endfire antennas
are run in anti-phase with a delay-line. This phasing also requires a design
that has zero interaction on the antenna inputs verses phasing/amplitude
adjustments.

One interesting phaser that may have been overlooked was designed by the
Late Graham Maynard in the late 1980s. He used a variable delayline to
provide a 90 degree phase shift with a fixed 180 degree phase reversal
transformer switched in 4 quadrants to provide 0-360 degree phasing. The
advantage of this scheme was a wider null bandwidth as it could be used for
an endfire array too.

73

Andrew Ikin

 

phasing units, then and now  View Printable Version 
Monday, July 09 2018

IRCA
Guy:


I've ben told the AFEDRI native software and HDSDR both support phasing. I have two problems with the AFEDRI: (1) it only records 600 kHz spans, and (2) phasing can only be done live. There's no way I know of to do phasing on recorded files. This is a shortcomimng that no one has solved for any SDR, as best I know.

Chuck

 

RFC - NCC-1 or NCC-2  View Printable Version 
Monday, July 09 2018

IRCA
I walked the spacing off today, it looks like roughly 175â from SAL to SAL center.

One of these will be a SAL-35, the second a SAL-30. I have more spacing options for a SAL-20 as the second SAL, up to a 400â.

> On Jul 7, 2018, at 9:30 PM, Neil Kazaross <neilkaz58@gmail.com> wrote:
>
> By all means phase two SAL's or similar if you have room. How far apart can
> you place them? 73 KAZ
>
>> On Sat, Jul 7, 2018 at 6:22 PM, Brandon Jordan <dxww.irca@gmail.com> wrote:
>>
>> Hi Colin. I missed this post somehow but, since seeing it, thought I
>> should respond. I own both the NCC-1 and NCC-2. I actually thought I sold
>> the NCC-1 last year on eBay but obviously did not as I just found it boxed
>> up in my radio room closet.
>>
>> I have way more experience with the NCC-1, mainly phasing dual DXE active
>> whips. I bought the NCC-2 from a ham who couldnât figure out how to use it,
>> but unfortunately since I put it online after a few months of being boxed,
>> I donât have any output out of antenna 2 so it is going to DXE for repair.
>> Long story short, no experience with the NCC-2 besides a few days of
>> testing when it first arrived. The NCC-1 worked great on two DXE active
>> whips spaced 100â apart.
>>
>> I have been so enamored with the Shared Apex Loop that regular phasers
>> have been a bit on the back-burner and why I am now very interested in your
>> new model. In speaking with the SAL guru Mark Bauman about dimensions on a
>> SAL-35, he mentioned phasing two SALâs could be very interesting and since
>> I happen to have two SAL units I am planning on experimenting with that. I
>> have the post holes dug, the 35â masts aluminum masts built and etc ready
>> to go but donât see me getting those up until it cools off some here in TN.
>>
>> 73,
>> Brandon
>>
>>>
>

 

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