Aerial and Microair radio

[LarryMcG]

Hi All

A new arrival with trike has a microair radio, and a aerial mounted on top of the Kingpost. This aerial is in two parts, one facing up, the other down, and may be a half wave aerial?

This is now to high to go into our hanger, and we need info or advice on what other type of aerial, and where to mount on a trike, using a different system, without anything on the Kingpost.

Any thoughts?

LM

[The Agent]

Larry to my limited knowledge the ariel with half top and the other half to the bottom is a much better areil type with reception and broadcasting better and clearer. prehaps you just have to move it.
Andre at Microflight Aviation at Rhino knows alot about these goodies.
012 7362519
Happiness.

[John Young]

This aerial is in two parts, one facing up, the other down, and may be a half wave aerial?

Hi,

The configuration is known as a vertically polarised dipole. If each element is approx. 580mm, then it is a quarter wave - a half wave would have elements some 1 160mm long.

A dipole does outperform a vertical whip - but only detectable on DX (long distance). For conventional trike radio work with our puny power output, a vertical whip is adequate as all radio work is line of sight dependent (up to 25 NM).

The question is – “Why not fit a conventional quarter wave vertical whip on the bowsprit”? Cost approx. R 125. If the SWR (Standing Wave Ratio) is set correctly, the radio "will not know the difference".

The following links will also assist, namely;

viewtopic.php?t=1625&highlight=swr

http://www.gregperkins.co.za/flying/dow ... ulator.xls

Regards
John ZU-CIB

[LarryMcG]

Thanks, will trey one from another trike first!

LM

[John Young]

Larry - news?

Regards
John ZU-CIB

[Cloud Warrior]

Is the aerial the Australian made Blackwidow 2000TT?

I have one fitted to my kingpost - luckily my current hangar is high enough to accomodate the extra height - but when I was hangared at Saldanha I had to lower the antenna to get in and out of my hangar. Performance was reduced but it was still better than the old whip aerial mounted on the bowsprit.

[ZULU1]

Hiya Larry

We have just designed and manufacture a replacement for the TT 2000, this is to be sold in the Oz market for the same problem that you advise. Also turn the power down on that unit to 1 watt as they are standard at 5 watts. I have done a few now and it improves them some what. Then should you have problems with the intercom balance (this by the way is guaranteed) call me and I have a fix for that also..and you will pick up power derived noise from the plane, I have a fix for that also..

Our antennas are made in cast ally and not PVC, the dipoles are fibreglass and sourced from our ski boat friends..they also prevent the rf ingress derived from the GPS 296 and others. They will also fit the Aquilla and other trikes, ideal for ships with pods. I have spent a few hours on this particular installation..

eish Zulu1

[Cloud Warrior]

Pictures and price please?

[ZULU1]

Hi All

The microair is designed for closed cockpit, they are a mission to balance for open usage as the two adjustments Mic gain and side tone are difficult to achieve.

They are standard with 5 watts.

To allow them to operate (and they do work well) I do the following:

Use the standard 4 wire connection from the Microair and disable the side tone in the chatterbox when the PTT is pressed, this prevents any ingress from the radio itself side tone.

I generate a "pseudo" side tone from the intercom so only the voice is transmitted out. The mic gain is no longer confused and allows clear transmission out.

I reduce the power (remove small sticker on lefte hand side) this is marked Microair inpection only.. turn to 1 watt.

I then add in our line chokes and regulators to prevent noise entering the cable network.

The nett result is it performs very well.

Pictures of the new antenna to follow as they are still very very new and expect to pay ex works about ZAR450,00.

eish Zulu1

[Griffin]

Zulu: What is the reason for reducing Tx power??

[ZULU1]

Because you dont need it..line of sight a ICA4 at 0,9 watts performs just the same and it reduces rf ingress into "anything", reduces draw on the network and makes no difference to performance in the air whatsoever.

Ciao Paul

[LarryMcG]

Gee You guys are Quik!

Ok, the trike is a Aussie one, so this does seem to be the problem.

Zulu, can you give me a price for the new antenae, with all the gadgets to get this sorted out for the fellow?

I will then pass this on, as he just moved here from Cato, and his email is not working yet.

Thanks for all the info

Larry

[John Young]

I will then pass this on, as he just moved here from Cato, and his email is not working yet.

Hi Larry,

You have got a good friend there - please pass our regards onto Sean Bailey alias SinBad and his lovely Missus.

Yeah - we miss ol' ZU-CZA.

WARNING – don’t go drinking with him – if the alcohol doesn’t kill you, his wife will.

Regards
John ZU-CIB

[FAWGie]

It's a pity that the microair doesn't have intercom squelch in addition to radio squelch.