[aklug] Re: Radio antenna help

HT would be Ham speak for handie-talkie A.K.A walkee-talkee.

Amateur Radio HTs used to commonly come with BNC type connectors for the
attached antenna, but with more compact modern ones SMA is most common.

HT antennas are also referred to as "rubber dummy loads", as while they
can be fairly wide-band they are not exactly high performance.

Alot of the dongle types use one form or another of micro-connector that
you will need to adapt over to a SMA, BNC or N type to connect to a
external feedline for a better antenna.

Many of the brick types come with a female SMA already.

Note, due to strange FCC regs for ISM type devices there are both the
"real" types and RP (reverse polorization) types.

Alot of 802.11 gear for example comes with a TNC-RP or SMA-RP connector
(where they swap the guts of the connector so the female body has the
male pin).

Need to be aware of the connector type your SDR uses and if it is the
-RP version (most re-tasked gear from the WiFi side of things uses -RP
types).

Adapter pigtail to BNC or N female. As in a 6 inch piece of small coax
with a SMA male on one end and a N female on the other.

For wideband fixed use, look at discones. Not high performance but
potentially very wideband. You have get ~ 36 inch tall discones that
will receive reasonable well from about 100Mhz to 2 - 3 Ghz. A 60-70
inch tall with tuned stinger may cover about 50Mhz to 1300Mhz.

Cost more, but there are models that support transmit in the 50 - 200
watt range (model dependant) over a subset of their range.

A discone mounted say 6ft above the roof with decent feedline running
into house is a very common wideband scanner antenna.

On 12/7/16 12:47, Hans Thompson wrote:
> Thanks Dave and James. What does SMA or HT stand for? There are just so
> many options when it comes to choosing an antenna and I'm new to the
> whole science of radio that it is difficult to figure out where to start.
>
> I've played around with AM/FM, reading utility meters, capturing my car
> key fob, and I'd like to now start capturing satellite transmissions but
> I'm wondering if the dinky SMA antenna I'm using needs an upgrade or
> repositioning. And then if it needs repositioning, what's the best way
> to run the cable out to the antenna. Up to now, I've only needed to run
> around with it connected to the usb in my laptop to get good reads.
>
> On Tue, Dec 6, 2016 at 7:37 PM, Dave H <dvhlgrt@gmail.com
> <mailto:dvhlgrt@gmail.com>> wrote:
>
> I've only played around with my sdr dongle a bit but there's some
> good exercises for gnu radio here: http://greatscottgadgets.com/sdr
> <http://greatscottgadgets.com/sdr>/
>
> Antenna design will really be driven by your desired use.
>
> -Dave
>
>
> On December 6, 2016 6:37:07 PM AKST, James Zuelow
> <e5z8652@zuelow.net <mailto:e5z8652@zuelow.net>> wrote:
>
>
>
> On 12/06/2016 04:31 PM, Hans Thompson wrote:
>
> Hi everyone. I've been a lurker for a couple months now.
>
> I'm looking for help with optimizing an antenna for software
> defined
> radio. I know this isn't related to linux but I'm sure there
> are
> folks out there with some experience that I can learn from.
>
> Thanks.
> Hans Thompson
>
>
> Hi Hans -
>
> I have a beaglebone black with a 7" LCD cape running Debian and gqrx. I
> plug a FunCube Pro+ into it.
>
> For UHF/VHF I just grab an SMA HT antenna and go. Putting gqrx into AM
> mode and walking around gives you a poor-man's RFI detector.
>
> For HF, I have a UHF -> SMA pigtail and I plug it into my HF antenna,
> but really all you need is wire, and a lot of it. One receiving antenna
> I've
> tested is a 90-foot roll of RadioShack 20-gauge black wire. Solder
> one end to the positive terminal of a UHF adapter, and put the other end
> into a convenient tree (with a little weight behind it). Thinking about
> it, I suppose that I could have soldered the wire to a male SMA adapter
> and dispensed with the pigtail, but aside from that a 90-foot roll of
> wire isn't "optimized" for much.
>
> I've thought about making a small loop for ARDF. The beaglebone could
> make a pretty decent 80m/2m combo detector just by swapping antennas.
>
> But what are you optimizing the antenna for?
>
> 73,
>
> James
> KL2ZZ
>
>
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>
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
>
>
>
>
> --
> Charles Hans Thompson
> Alaska Statistical Automation
> Chief Data Scientist
> (360) 628-3860
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Received on Thu Dec 8 11:45:47 2016