Mono Band Mobile Whips - any experiences?

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GW0DIV
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Re: Mono Band Mobile Whips - any experiences?

Postby GW0DIV » 20 Aug 2011, 16:01

northern35s wrote:
buggerlugs wrote:That antenna looks remarkably like a Sirio CB antenna, are SRC converting CB antennas for use on amateur radio? Good on them if they are.



:shock: :shock: :shock: I've already got one, its called a Sirio S3000 and cost a lot less :shock: :shock: :shock:



I think you're missing the point, Sirio build the antenna using their parts. It's not just the CB antenna rebadged - I think it's probably a balun/unun type of arrangement, similar to the Chameleon. It looks like the Sirio because it's built in a Sirio casing, but the innards are designed by SRC.

I think the CB antenna costs around £40, the SRC costs £60 - £50 at rallies, so not much more for an antenna that covers more. I'm very pleasantly surprised with it so far. It'll never be a full size dipole but for a six foot mobile whip it's not bad at all.
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Re: Mono Band Mobile Whips - any experiences?

Postby StoatTB » 22 Aug 2011, 17:23

Okay, at this stage I've pretty much ruled out an 80m mono band mobile whip, unless it's good for inter G at night? Out of the higher band ones e.g. 20m, 17m, 15m, etc. what brands would people avoid and what brands would you recommend? I'm looking at the budget versions of up to £25 maximum, with a 3/8ths mount (no mobile use, only portable).

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Re: Mono Band Mobile Whips - any experiences?

Postby Ashdown_Ratchet » 22 Aug 2011, 18:53

I've got ones for 20 and 40, got them from eBay here http://stores.ebay.co.uk/comm-engineer, they seem OK, about as good as short verticals are likely to get.... they seem to meet your criteria too, cheap and 3/8th mount.

AR

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Re: Mono Band Mobile Whips - any experiences?

Postby StoatTB » 23 Aug 2011, 13:04

Yeah, I am watching those on eBay at the moment. ;)

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Re: Mono Band Mobile Whips - any experiences?

Postby 26TM944 » 23 Aug 2011, 13:40

Hi,

I have a AMPRO-20 and a WATSON 6 - they both look very much the same. The 6m one is more or less all fiberglass and about 6" of whip at the end to get it tuned to the bottom end of 6m. The 20 is *BIG* and does work OK - not mega but good enough for static mobile - I don't know if I would trust the 3/8th mount with the whip on it without a h/d spring.

SWR is good but very narrow on the AMPRO-20. You do really need to choose where you are going to use it to keep it below 2:1 - mines tuned about 14.250 from memory.

I do fancy a CHAMELEON v1 with unun for /P as that seems to be the nearest to something decent multiband - but they are a lot of £ for something on a whim. I wonder if my 102" SS whip and unun will work as well - I don't really see much between them - as you're looking for 108" with a mount and spring I am pretty much near that length.

May see if at the MK rally they have something there to test as I know Moonraker are going. They might let me test a couple of antennas out. Hopefully a band or two might be open.

But the 6m version works very well. Had some good DX on that /P

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Re: Mono Band Mobile Whips - any experiences?

Postby GW0DIV » 24 Aug 2011, 20:02

I think the SRC8010 is some kind of chameleon clone. I suppose you could always wind a 9:1 balun and put it on the bottom of a 6 foot plus CB whip.
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Re: Mono Band Mobile Whips - any experiences?

Postby Adriano9966 » 24 Aug 2011, 22:18

:) I have no problem getting up early to work dx 6am 5am 4am even 1.30 am I have done the lot.

:| As Stephen told me the other day location location what I really need is a house by the sea preferably on the west coast by the sound of it.

;) Still on the positive side I have three monoband whips purchased from Thunderpole in Northampton 20/40/80 metres . I now have a multi band vertical to shove on the chimney stack and god willing this weekend a 2metre/70cms colinear to set up in the back yard alongside (lower than)my hf4b .So that should give me adequate coverage from 80metres to 70 cms from home.

I shall fix the mobile set up next so that will give me a chance to test a few of these monoband whips.

:) I'm no expert just an enthusiast but on a side note I was wondering why they are all base loaded ? Is this just for practicality given the size of the coil?
Surely up on the higher bands 17/15/12/10 metres centre loaded would be better for a lower angle of radiation or am I talking nonesense here?

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Re: Mono Band Mobile Whips - any experiences?

Postby northern35s » 25 Aug 2011, 06:34

Centre loading is the way to go for efficiency and the ability to drive with it attached, however capacitive top loading is the most efficient way to load a short vertical, but they are a tad ungainly and prone to damage when trudging down the motorway. Centre loading moves the current maximum away from the vehicle body and further away from lossy earth, the current distribution tapers off sharply above the loading coil, so if it is base loaded it suffers the most loss, if we capacity load the antenna at the top then we have almost a linear current distribution along the antenna, another benefit of capacitive loading is extra bandwidth. If I capacitively load my screwdriver antenna it's good for another 6dB gain on 40m, but that is only good up to about 40Mph before the cap hat gets bent out of shape, my large centre loaded antennas are good for 60Mph, but put a massive strain on the mount and leads to mount failure over a period of time.

Adrian if you can't get by the sea, get high and clear of houses and buildings, this does two things, a perfect take off for your signal and it also gets you away from man made noise, hill topping has always been a good way to DX ;)

ps. 17m shouldn't be overlooked, you WILL work Japan on there any day this week with a reasonable antenna on the car, I've had some excellent contacts on 17m when 20m was dead.
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Re: Mono Band Mobile Whips - any experiences?

Postby Adriano9966 » 25 Aug 2011, 09:08

:D Thanks I will be mobile on hf very soon there is a large choice of decent heights around here. Burton dasset, Edgehill,Rollright, etc just need to save a bit of dosh to sort it all out properly.Quite right about top loaded antennas cracking the mount I had this happen with a 7' firestick many years ago but I think the whips I have I would only use parked up anyway.
I want to mount a transceiver permanantly in my car as I think this is the best option .

When operating eg in france on the cb and hill topping I have been using some unsightly fly leads and the transceiver on the front seat or sat on the dash board.
During recent Christmas day greetings on the air I used my 2metre handy(500mw output) from Edgehill with a quarter wave but I think this is more adequate rather than Ideal .
:) I need to save a bit of cash for an ft817nd as this would give me more versatile operation for mobile plus the bonus of having all bands right up to 70 cms.
In the meantime I will carry on with some unsightly fly leads ;)

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Re: Mono Band Mobile Whips - any experiences?

Postby 26TM944 » 25 Aug 2011, 13:42

GW0DIV wrote:I think the SRC8010 is some kind of chameleon clone. I suppose you could always wind a 9:1 balun and put it on the bottom of a 6 foot plus CB whip.


Darn. That SRC8010 looks like my SIRIO 4000 - in fact I bet they are the bloody same! You can tune my 4000 with an ATU to match anywhere (bar 6m) but I bet it wont radiate any more than the coax that feeds it below 20m ...

I think the 108" whip and 9:1 UNUN is going to be the test. I'll be at the MKR on Sunday will have a look for some antenna building bits.
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Re: Mono Band Mobile Whips - any experiences?

Postby StoatTB » 25 Aug 2011, 15:49

I've taken the plunge and have bought an 80m mono band whip from eBay. I was speaking to some friends at the local radio club and one has had some good success on inter G nets at nights, etc. That's what I'm looking for, not a DX monster. ;)

I'll probably get some higher bands ones later, i.e. 20m, 17m and 15m.

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Re: Mono Band Mobile Whips - any experiences?

Postby G0TVJ » 25 Aug 2011, 16:16

26TM944 wrote:I think the 108" whip and 9:1 UNUN is going to be the test. I'll be at the MKR on Sunday will have a look for some antenna building bits.

This was what I used before I set up my present arrangement (see signature). My LDG AT-897 could match it from topband to 6m. As you would expect, it was pretty hopeless on topband and 80m but it worked well enough on 40m and from 30m upwards it was a decent aerial.

I had it mounted on the rear wall a few feet above gutter height. I intend to put it back together soon with a separate feed so I can switch between the whip and the horizontal wire.

In the end it's just a 9ft whip and it's never going to be a wonderful antenna but if you are pushed for space and need something simple to get you on the air I think you'll be pleasantly surprised at how well it works on the higher bands.

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Re: Mono Band Mobile Whips - any experiences?

Postby brianford5mhz » 25 Aug 2011, 16:32

>don't mention the rf burn to my mic hand LOL

Try running the whip with a direct to chassis earth connection instead
of a magmount.

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Re: Mono Band Mobile Whips - any experiences?

Postby StoatTB » 25 Aug 2011, 17:07

brianford5mhz wrote:Try running the whip with a direct to chassis earth connection instead of a magmount.


Not easy on a steel portacabin. :lol:

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Re: Mono Band Mobile Whips - any experiences?

Postby brianford5mhz » 27 Aug 2011, 07:11

buggerlugs wrote:
brianford5mhz wrote:Try running the whip with a direct to chassis earth connection instead of a magmount.


Not easy on a steel portacabin. :lol:


Bah! Ok here's another possible solution.

Attach a quarterwave wire to the back of the radio's grounding lug.

This should shift the high voltage point that appears at the rig away from the
rig. It's not critical, anything about 33ft will do. No need to tune anything.

Good luck.


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