Mini whip active aerials? - UK Vintage Radio Repair and Restoration Discussion Forum

Tractionist · 30th Jan 2018, 6:04 pm

Anyone had any experiences [good. bad or indifferent] with these? I'd appreciate any tales of your travails ......

MrBungle · 30th Jan 2018, 6:35 pm

Also interested

Herald1360 · 30th Jan 2018, 6:47 pm

Depends how mini to some extent.

Obviously only good for receiving.

Trickiest part is the active bit. It's a wide open broadband amplifier which has to be up to coping with strong local signals without generating loads of intermodulation products to flatten the weak signal you want to hear.

cmjones01 · 30th Jan 2018, 10:06 pm

I think the online SDR at the University of Twente in the Netherlands uses a miniwhip:

http://websdr.ewi.utwente.nl:8901

I've just tried it out and it works very well. Try it yourself!

Chris

PeterRoberts · 1st Feb 2018, 11:21 pm

I built one of the PA0RDT mini-whips and it works well enough. However, it is good at picking up electrical noise, so for best performance needs to be situated high and away from any buildings or power lines. A good ground is also needed. Some further info here.

I found it performs much better than a random wire antenna for picking up NAVTEX signals on 518 kHz and 490 kHz.

David G4EBT · 2nd Feb 2018, 11:16 am

Some years ago the Drucker 'Miracle Whip' tunable antenna was in vogue, which it was claimed tuned from 3.5 MHz - 450MHz at no worse than 2:1 SWR. Only for QRP, no more than 15W PEP. The telescopic whip was originally 56" long as I recall. I don't think there was a lot in it - a tapped toroid inductor, but I don't know what else. (Snake oil maybe?). Lots of write-ups and reviews on internet about it. I think it was American and was favoured for use with the Yaesu FT817, which I think has a built in ATU.

I've no experience of them and didn't know anyone who bought one.

I see that '2017' Miracle Whips are on sale from several suppliers in China on ebay.

Google '2017 version QRP Miracle Whip Antenna' will find it, along with pics and spec.

It evokes memories of the 'Joystick' miracle antenna of yesteryear.

Nuff said.

G8HQP Dave · 2nd Feb 2018, 11:58 am

When it comes to antennas, there is no crock of gold at the end of the rainbow - however sincerely inventors may believe that there is. Even inventions which work don't necessarily work in the way the inventor believes. The best you can do is have an appropriate antenna for your requirements in your situation. In some cases this could be an active mini whip.

PJC58-Hythe · 2nd Feb 2018, 2:29 pm

I've made one of these and it works very well, the only caveat is that it needs a good ground plane, or mounted up high with a separate ground lead and it definitely needs to be away from noise sources!

I've attached the article by PA0RDT for anyone who is interested.

G6Tanuki · 2nd Feb 2018, 2:38 pm

A long time ago when temporarily living somewhere I couldn't put up a big antenna I made use of a Datong "AD170" active antenna: a small square waterproof box with a pair of rods sticking out the sides, powered from 12VDC down the coax.

Mounted on a broomhandle and tied to the vent-pipe of my flat it worked surprisingly well as a Band-I/II TV- and FM-DX antenna to get me access to summertime Sp.E openings. Gdansk on 70.31MHz was the station 'everybody' listened-for as a hint that there was a lift approaching.

Nuvistor · 2nd Feb 2018, 2:45 pm

I had to use one of those Datong aerials, this was for HF, this used two approx 3m wires and I slung those in the attic with the active amp in the centre, coax fed to the radio and voltage for the amp fed via the coax.
It worked extremely well, the active amp didn’t have any problems with third order products. I could overload the radio though around 6-7MHz but that had a built in switched attenuator .

This was long before all the interference on MW and SW that we now have.

G8HQP Dave · 2nd Feb 2018, 4:18 pm

I believe PA0RDT originally claimed low noise for his antenna. Theory suggests not, and experience of others seems to confirm this. The Datong antenna, being essentially a short dipole, should be much quieter as local longitudinal electric field noise will largely cancel. So of you want a short active whip, better to have two arranged as a dipole.

raditechman · 2nd Feb 2018, 5:56 pm

I also built an active whip antenna based on the PA0RDT circuit. Works OK but finding a noise free place to put it is a problem for me so I stick to my external aerials which I well away from the house.
I know a few other people who have built them and have found them useful.

John

Tractionist · 5th Feb 2018, 6:08 pm

Thanks guys - as I suspected ...... a bit suspect!

laserbill · 14th Feb 2018, 9:48 pm

Hi Guys,
My first post in this terrific forum.
I am using an active mini whip in my loft with great results.
Its particularly good from 100 KHz to 1.6 MHz and works well up to 30 MHz
not as good as my 200 ft long wire but its impressive.
Its made by a Russian amateur called Anton, call-sign RA0SMS.
Shipping is super quick and he answers all questions
http://www.ebay.co.uk/itm/Mini-Whip-...9/201710114976
Regards
Bill

30th Jan 2018, 6:04 pm	#1
Tractionist Heptode Join Date: Apr 2016 Location: Cheltenham, Gloucestershire, UK. Posts: 875	Mini whip active aerials? Anyone had any experiences [good. bad or indifferent] with these? I'd appreciate any tales of your travails ...... __________________ Red to red, black to black. Throw the switch and stand well back!

30th Jan 2018, 6:35 pm	#2
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Mini whip active aerials? Also interested

30th Jan 2018, 6:47 pm	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Mini whip active aerials? Depends how mini to some extent. Obviously only good for receiving. Trickiest part is the active bit. It's a wide open broadband amplifier which has to be up to coping with strong local signals without generating loads of intermodulation products to flatten the weak signal you want to hear. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

30th Jan 2018, 10:06 pm	#4
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Mini whip active aerials? I think the online SDR at the University of Twente in the Netherlands uses a miniwhip: http://websdr.ewi.utwente.nl:8901 I've just tried it out and it works very well. Try it yourself! Chris __________________ What's going on in the workshop? http://martin-jones.com/

1st Feb 2018, 11:21 pm	#5
PeterRoberts Pentode Join Date: Dec 2011 Location: Camberley, Surrey, UK. Posts: 145	Re: Mini whip active aerials? I built one of the PA0RDT mini-whips and it works well enough. However, it is good at picking up electrical noise, so for best performance needs to be situated high and away from any buildings or power lines. A good ground is also needed. Some further info here. I found it performs much better than a random wire antenna for picking up NAVTEX signals on 518 kHz and 490 kHz.

2nd Feb 2018, 11:16 am	#6
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,761	Re: Mini whip active aerials? Some years ago the Drucker 'Miracle Whip' tunable antenna was in vogue, which it was claimed tuned from 3.5 MHz - 450MHz at no worse than 2:1 SWR. Only for QRP, no more than 15W PEP. The telescopic whip was originally 56" long as I recall. I don't think there was a lot in it - a tapped toroid inductor, but I don't know what else. (Snake oil maybe?). Lots of write-ups and reviews on internet about it. I think it was American and was favoured for use with the Yaesu FT817, which I think has a built in ATU. I've no experience of them and didn't know anyone who bought one. I see that '2017' Miracle Whips are on sale from several suppliers in China on ebay. Google '2017 version QRP Miracle Whip Antenna' will find it, along with pics and spec. It evokes memories of the 'Joystick' miracle antenna of yesteryear. Nuff said. __________________ David. BVWS Member. G-QRP Club member 1339.

2nd Feb 2018, 11:58 am	#7
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: Mini whip active aerials? When it comes to antennas, there is no crock of gold at the end of the rainbow - however sincerely inventors may believe that there is. Even inventions which work don't necessarily work in the way the inventor believes. The best you can do is have an appropriate antenna for your requirements in your situation. In some cases this could be an active mini whip.

2nd Feb 2018, 2:38 pm	#9
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,996	Re: Mini whip active aerials? A long time ago when temporarily living somewhere I couldn't put up a big antenna I made use of a Datong "AD170" active antenna: a small square waterproof box with a pair of rods sticking out the sides, powered from 12VDC down the coax. Mounted on a broomhandle and tied to the vent-pipe of my flat it worked surprisingly well as a Band-I/II TV- and FM-DX antenna to get me access to summertime Sp.E openings. Gdansk on 70.31MHz was the station 'everybody' listened-for as a hint that there was a lift approaching.

2nd Feb 2018, 2:45 pm	#10
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Mini whip active aerials? I had to use one of those Datong aerials, this was for HF, this used two approx 3m wires and I slung those in the attic with the active amp in the centre, coax fed to the radio and voltage for the amp fed via the coax. It worked extremely well, the active amp didn’t have any problems with third order products. I could overload the radio though around 6-7MHz but that had a built in switched attenuator . This was long before all the interference on MW and SW that we now have. __________________ Frank

2nd Feb 2018, 4:18 pm	#11
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: Mini whip active aerials? I believe PA0RDT originally claimed low noise for his antenna. Theory suggests not, and experience of others seems to confirm this. The Datong antenna, being essentially a short dipole, should be much quieter as local longitudinal electric field noise will largely cancel. So of you want a short active whip, better to have two arranged as a dipole.

2nd Feb 2018, 5:56 pm	#12
raditechman Heptode Join Date: Feb 2007 Location: West London, UK. Posts: 867	Re: Mini whip active aerials? I also built an active whip antenna based on the PA0RDT circuit. Works OK but finding a noise free place to put it is a problem for me so I stick to my external aerials which I well away from the house. I know a few other people who have built them and have found them useful. John

5th Feb 2018, 6:08 pm	#13
Tractionist Heptode Join Date: Apr 2016 Location: Cheltenham, Gloucestershire, UK. Posts: 875	Re: Mini whip active aerials? Thanks guys - as I suspected ...... a bit suspect! __________________ Red to red, black to black. Throw the switch and stand well back!

14th Feb 2018, 9:48 pm	#14
laserbill Diode Join Date: Feb 2018 Location: West Yorkshire, UK. Posts: 6	Re: Mini whip active aerials? Hi Guys, My first post in this terrific forum. I am using an active mini whip in my loft with great results. Its particularly good from 100 KHz to 1.6 MHz and works well up to 30 MHz not as good as my 200 ft long wire but its impressive. Its made by a Russian amateur called Anton, call-sign RA0SMS. Shipping is super quick and he answers all questions http://www.ebay.co.uk/itm/Mini-Whip-...9/201710114976 Regards Bill