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VHF Comm's upgrade


youngmic
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Hi All,

 

I have recently had my old Collins 251 VHF's expire, both inside a week.

 

So time to upgrade, unfortunately I don't have the panel space for a flat type (icom A 200) so I am looking at filling the existing space from the Collins with one of the following: Xcom, Microair, Becker, or Flightline.

 

The aircraft in question is a composite construction Vari-eze and has all the associated issues of radios in composite airframes. Zulu's and Altronics headsets will be used and either PTT intercom or true adjustable VOX capability is preffered. I have heard one unit claims VOX but is open mike all the time?

 

I have been advised to steer clear of the Xcom from a tech but must admit it was/is my first choice at this stage.

 

Any advice on the following would be greatly received: Company after sales support and what they are like to deal with, warranty issues and effectiveness, unit performance, clarity, range etc. Reliability and parts back up.

 

If anyone has a servicable Collins 251 for sale I could be interested.

 

Please feel free to PM me if you wish to maintain anonymity.

 

Regards

 

Mick

 

 

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Mick

 

I put an Xcom in a new J230 that I built and am very happy with it since it started flying last Feb. At the time I also felt that the built in intercom was an advantage for that unit.

 

Also have a Dittel in my sailplane and that has given excellent service too.

 

Michael Coates is a member of this forum. Suggest you PM him with the dtails of the concerns expressed by your tech mate and see what Michael has to say.

 

Hope this helps.

 

Regards Geoff

 

 

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I have an Xcom since I liked the idea of intergrated intercom and wanted a CB linked into it.

 

When delivered in Australian factory built aircraft its performance was poor. Via the aircrafts maker questioned Xcom and Michael took a detour on the way to a family holiday and found the problem...a substandard aerial installed by the (aircraft) maker.

 

Not long later was receiving intermittent screaching via the radio. Raised it with Michael and his people at Narromine 08 and he/they were very helpful. Problem did not go away so arranged to fly down and see Michael on a weekend where the cause of the problem, a transponder NOT manufactured by Xcom, was isolated as the problem.

 

Transponder as repaired under warrentry and problems stopped.

 

I cannot fault Xcom product support. These days this is not common. When I need another radio who do you think I will be seeing first??

 

 

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Guest Michael Coates

Thanks for the support guys, happy to answer any questions either on or off group. [email protected] Dont know what the problem would be with the tech guy (we dont have anyone in WA) so would be interested to hear any info, thanks Michael

 

 

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G'day Michael C.,

 

I am not sure of the orgins of the techs concerns but will be speaking with him again soon. I suspect it maybe a carry over impression from the earlier models of which both Microair and Xcom had some issues.

 

At this stage your product is looking very good and the confidence of a 3 year warranty is worth noting.

 

It appears antennas are a sore point with radios and I have had some issues in this area in the past as well. At present I am using a S/S whip clipped to length under the belly of the eze, it has not been SWR'd but seems to work fine, reception across the Nullabor is quiet good.

 

I have seen an example of a dipole on an eze in the states where the chap used the thick (2mm ish) single strand copper house wire stripped of its sheath and fixed to the trailing edge of the main landing gear bow which is fibreglass. Apparently reports say that it works exceedingly well but I do not know what radio was installed.

 

I would like to try this type of installation to gauge its merits as I would suspect that it would be an improvement on the S/S whip and a drag reduction to boot. I physically cannot bring myself to install a Comant 121 and I even bought and sold one at a loss unused simply because of its weight penalty.

 

What are your thoughts on the matter, can you recommend a low drag, low weight effective antenna compatible with the Xcom 760.

 

Regards

 

Mick

 

 

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Guest Michael Coates

am not sure of the orgins of the techs concerns but will be speaking with him again soon. I suspect it maybe a carry over impression from the earlier models of which both Microair and Xcom had some issues.

 

At this stage your product is looking very good and the confidence of a 3 year warranty is worth noting.

 

It appears antennas are a sore point with radios and I have had some issues in this area in the past as well. At present I am using a S/S whip clipped to length under the belly of the eze, it has not been SWR'd but seems to work fine, reception across the Nullabor is quiet good. Be careful here... RECEPTION: You can receive on a wet piece of string, but transmission is another matter, the best VHF aerial in our testing has been the comant 121, the problems with the stainless whips are well known and are generally not very good at broad band performance. We have a Aerial Dummies Guide which is worth a read to get more information.

 

http://www.mcp.com.au/xcom760/education/XCOM-Aerial-Dummies-Guide.pdf

 

I have seen an example of a dipole on an eze in the states where the chap used the thick (2mm ish) single strand copper house wire stripped of its sheath and fixed to the trailing edge of the main landing gear bow which is fibreglass. Apparently reports say that it works exceedingly well but I do not know what radio was installed.

 

I would like to try this type of installation to gauge its merits as I would suspect that it would be an improvement on the S/S whip and a drag reduction to boot. I physically cannot bring myself to install a Comant 121 and I even bought and sold one at a loss unused simply because of its weight penalty. You get what you pay for, the problem with a thin aerial is broad band performance, you can for example tune it to 118 mHz and it will work well but try TX on 136 mHz and it will be terrible, thats why the thicker aerials work the best (see dummies guide)

 

What are your thoughts on the matter, can you recommend a low drag, low weight effective antenna compatible with the Xcom 760. Comant 121 or a good quality dipole installed internally (results vary widely)

 

 

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I have an Xcom in my cheetah, seems to work fine except for one thing: the AFRU at Moruya never recognises it. It has a Comant 121 aerial with professionally terminated couble shielded wire.

 

Everyone else seems to hear it, and well enough I supposes, no-one has mentioned it being faint, and I can hear others clear enough, but the AFRU which works for everyone else all the time never hears me.

 

Any ideas?

 

I haven't tried any other airport with an AFRU, so I can't tell if they all do the same....

 

 

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Thanks for that.

 

Have read your dummies guide in the past but thanks anyway.

 

Comant 121 is a non starter for this aircraft, that is why I sold it. Similarly you won't ever see a 121 on a sailplane but the Xcom is marketed specifically at this group.

 

What are they using and what are the typical mixed results you mentioned

 

Can you offer any specifics on the matter of antennas.

 

Regards

 

Mick

 

 

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I know several people who have had or still have Microair radios. The general concensus is that they are not as good as the advertising makes them out to be. I must admit that I have never used one, but there must be something wrong for people to dump them.

 

 

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Guest Michael Coates

Most of the glider aircraft use an internal aerial bonded into the rudder of the aircraft. They don't normally put them elsewhere in the fuselage because they work best when they are vertical and also many of these aircraft are made from carbon fibre which is nonconductive and this means that the aerial will not work. This is why they usually put them in the rudder which they then make out of fibreglass specifically for the aerial to work. Most of these types of aerials are strips of copper for another acceptable material usually about 2 mm thick by 15 mm wide by the length required to get an acceptable VSWR. There are a number of companies which make these aerials but they must be installed during manufacture of the aircraft.

 

 

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