Helical

[hfflunki]

I made this today because my room Is big enough for a indoor short wire and am not able get outside it has to be grounded to work better than just a short wire

 

[hfflunki]

Yup it works just got some ham activity on 40meters no it looks dark enough for mw I use loops for that

 

[mmckenna]

Building your own antennas can be a lot of fun. Any plans for your next one?

 

[nanZor]

I like it!

Is the entire tube helically wound, or just the black part that looks kind of like an inductor coil wound about 2/3 of the way up the pvc?

In either case, you can add additional capacitive or "top hat" loading, but in a room a "hat" is hard to do.

In this case, I would run a wire horizontally across the top, perhaps just along the rod that support(ed) the blinds, and in the middle of that wire, attach it to the top of your small vertical. Mechanically it just looks like two wires attached to the top of the vertical, each one running directly opposite and horizontally from each other for a few feet or two.

Adding capacitive reactance like this to the top of any vertical, especially one with a lot of coil inductance, helps.

 

[hfflunki]

Thanks

 

[hfflunki]

Hertzian actually it's a single wire coiled a 1/2" dowel and a wire solders to the ground on the plug tipped with solder for connection to a ground when possible I tried conecting one end to g and one to live but ther isn't enough gain as far as length of coil I used around 50 ft most are 100' of wire

 

[hfflunki]

this is a picture of the element
Coil

 

[majoco]

Did you get the idea from here....?

Broomstick Special, easy-to-build shortwave antenna -- on hard-core-dx.com

 

[hfflunki]

That's one of them this is what I came up with finished

 

[hfflunki]

helical / 42 Links - Page 1
this is a good start

 

[hfflunki]

Well been testing it on swbcb using a 909x works very well picked up all the main religious station as well as rhc and a few I couldent tell what laungege that was being spoken on 49m didn't get at it till 1utc and checked the main pirate freqs just below 40 m and haven't been able to get them picked up some Cw and ham activity will give radio Australia a try in the morning

 

[nanZor]

Nice! Good ol' Arne and the broomstick.

Unfortunately what one ends up with when there is no spacing is more or less a high-resistance emulation of just a small piece of tubing, overloaded with too much inductance usually, unless one is trying for 160m or so.

You are on the right track though. How about the following for some ideas on improvements, like centering up at about 14mhz? :

A Two Dollar Helical HF Portable Antenna

Even though cut for an amateur band, a few more or few less turns can put this onto 13m or 16m easily, and be a general purpose vertical template for other bands - like using FAR less or FAR more turns to get to the bands you want.

The pics at the bottom are very good. Use pvc instead of wood doweling to cut down on loss. Space the wires. You could even use what you have now either adding or removing turns as you wish. Make the "stinger" longer or smaller. If you have to bend the stinger indoors, so be it. Or put a top-load wire on top of the stinger.

Food for thought anyway... but good work so far!

 

[hfflunki]

Thanks I know PVC and spacing can work better but am in limited space and need a lot of gain I've started construction on a module that has a RCA out and banana post for ground and have purchased a home brew antenna amplifier that was 25 bucks on e eBay I plann on mounting it all on the platform this is the amp I'm going to add a metal battery holder for the 9volt



Sent from my iPhone using Tapatalk

 

[SpectreOZ]

If you're looking for good performance and you've got limited space I suggest you look into loop antennas to accompany your RF amp as they generally have a lower noise floor and are a closed (independent) antenna design.

A Magnetic Loop Antenna for Shortwave Listening (SWL) - KR1ST


Just curious which DIY kit you went with... was it the Ramsey SA7 Preamp?

 

[hfflunki]

Looks good but I need somthing smaller than 5 feet I realize this antenna will be noisy that's why I added a ground and I will probably use a magnetic loop if I'm ever able to get outside

 

[SpectreOZ]

With a good pre-amp you can get away with a smaller loop design just look at the Sony AN-LP1 or the Kaito KA33.

 

[hfflunki]

Ya I was debating building another loop but wanted somthing more portable this one will be small enough to fit in a case with my 909 as far as the ka33 is concerned they work good but are poorly built and often break. The amp I bought on ebay http://www.ebay.com/itm/230466589086

 

[hfflunki]

well this is it woks great from 31metters up and alittle noisy on down to 49meeters anything lower is noise I added a spot to connect the short wire addition wich helps the lower frequencys and each antenna is grounded on separate circuits don't ask me how it's done I just came up with a simpe desieghn and my freain added some stuff when he solders it up still got the amp coming it will sit at right angle that's what the battery holders for

 

[hfflunki]

http://youtu.be/DCeI7eeHrLw
Video of antenna picking up radio Australia 9 utc 9.58mhz

 

[hfflunki]

Sorry bad link here's the good one http://youtu.be/ial12O6SmNk