HF Radio Aerial Question

Submitted: Wednesday, Mar 26, 2008 at 14:53

ThreadID: 55937 Views:2165 Replies:3 FollowUps:12

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Mike

I have a Coadan NGT with Auto tune aerial...... Question you know how UHF radio aerials have the twirley bit in the middle of the aerial........do they make HF whips similar and if so where can I purchase one? as I would prefer a shorter whip than the 1.6m that I am using and I would be able to use my carport and not having to take the whip off all the time.

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Reply By: Member -Signman - Wednesday, Mar 26, 2008 at 15:03

Wednesday, Mar 26, 2008 at 15:03

The centre loading on a UHF is very different to that of HF.
I assume you are using a Codan 9350 Autotune ?? If so- you can get away with using a shorter whip, but this may limit the usage of the very low frequencies in the band. You'll be able to use mid frequencies (eg 5455 & 8022).
I have even used and old 27mHz CB antenna on a 9350- it was about 900mm. Tune up and worked with no probs.
If you are using the 'solid' fibergalss whip - you can get a stainless 'wire' whip- more flexible and works just as good.

AnswerID: 294829

Follow Up By: Member - Phil G (SA) - Wednesday, Mar 26, 2008 at 18:32

Wednesday, Mar 26, 2008 at 18:32

Just to add, that if using the flexible stainless wire whip, its pretty easy to pull it down with a string tied to the roofrack.

FollowupID: 560759

Follow Up By: Stu & "Bob" - Wednesday, Mar 26, 2008 at 22:07

Wednesday, Mar 26, 2008 at 22:07

The secondary s/s whip that used to come with a new 9350 is only 1.2m long. Very flexible, more so than the 1.6m s/s whip.
Down side is that it won't tune 2020.

Maybe an engineering works could make up one? After all, it is only a piece of s/s rod. I don't know if this would work, but it might be worth a try. A few coils in the middle should reduce it's height, just make sure they cannot touch one another.

HTH

FollowupID: 560823

Reply By: Footloose - Wednesday, Mar 26, 2008 at 15:15

Wednesday, Mar 26, 2008 at 15:15

Bushcom
RHS Popular products
Number 31 Codan

AnswerID: 294830

Follow Up By: jdwynn (Adelaide) - Wednesday, Mar 26, 2008 at 19:41

Wednesday, Mar 26, 2008 at 19:41

Footloose, I noticed the site also has a 'Firecracker' emergency antenna ($165). Have you any thoughts about that - or is a simple wire one just as good (something Ive never gotten around to getting/making). Cheers JD

FollowupID: 560768

Follow Up By: Footloose - Wednesday, Mar 26, 2008 at 20:03

Wednesday, Mar 26, 2008 at 20:03

JD, have seen one and looks good and works well. But what are the chance of you ever needing one ?

FollowupID: 560775

Follow Up By: jdwynn (Adelaide) - Wednesday, Mar 26, 2008 at 20:10

Wednesday, Mar 26, 2008 at 20:10

Hard to answer that. In our case it would need a car roll-over perhaps. Not cheap. Basically I've been slowly attending to risks - carry a spare mic now (as per your previous comment - Murphy will hate me!!). Upgraded my Series A 9350 with Series D bits now. So emerg. antenna was next thing on my list. Will think on it. cheers JD

FollowupID: 560779

Follow Up By: Member -Signman - Thursday, Mar 27, 2008 at 08:34

Thursday, Mar 27, 2008 at 08:34

'Morning JD
What frequency (channel) do you use most of the time??
What I'm getting at- if you are concerned about damage to your autotune- maybe just a long wire to get you out of trouble !!
eg- I think for 8022kHz (VKS Ch2) is about 7900mm long (Footloose will confirm)- with an insulator & piece of string.
I have one wrapped on a fishing line ring in the spares drawer..

FollowupID: 560875

Follow Up By: Footloose - Thursday, Mar 27, 2008 at 08:43

Thursday, Mar 27, 2008 at 08:43

Signman, yep around 29'6" in the old measure. The problem is that while it will work, the feed impedance changes; depending upon earthing, where it is actually attached to the vehicle etc. It even changes between the vehicle being on its side to if it's upside down ! Nevertheless, it should get you out of strife.

FollowupID: 560876

Follow Up By: jdwynn (Adelaide) - Thursday, Mar 27, 2008 at 08:44

Thursday, Mar 27, 2008 at 08:44

Hi Signman
Mostly 8022. I am seriously (seriously) deficient in things electrical (!!). How do you connect wire when say antenna smashed. Also, what wire, what insulator and why string. (Hence why I thought firecracker might be the way for me LOL). cheers JD

FollowupID: 560877

Follow Up By: Member -Signman - Thursday, Mar 27, 2008 at 08:52

Thursday, Mar 27, 2008 at 08:52

Over to you Jim !!

FollowupID: 560880

Follow Up By: Footloose - Thursday, Mar 27, 2008 at 08:58

Thursday, Mar 27, 2008 at 08:58

JD, if you are that worried about a rollover, I'd go the firecracker. But remember that aerials and batteries etc might suffer in an accident. The only way to cover all your bases is to carry a satphone in a small metal box. You can just use a Telstra simcard for an emergency, and still have the convenience of HF normally.
A Motorola 9500 s/h on Ebay is going to cost you around $800.

FollowupID: 560882