Dipole for DTR radios

[Lowboy23]

Has anyone tried this antenna for DTR radios-Motorola part # 8505884r02? Here is a good photo and price of the antenna-https://www.batterydistributors.com/motorola-8505884r02-dipole-antenna.html. Same connector. Same frequency cut. No lossy matching network because it is a dipole as opposed to the end-fed stock and 7-inch normally offered for the radios. I see no reason why this antenna would not work. Admittedly, this antenna is not going to make a huge difference over the 7-inch antenna, but for distance junkies every little bit helps.

 

[n1das]

Should work well. Great find!

I have a fleet of DTR650 radios and they work excellent. They have completely replaced my use of GMRS/FRS for my local on-site simplex type use with family and friends. These radios provide an all-digital solution that's higher quality and more professional than GMRS/FRS. I also have a fleet of DLRs and they work with my DTRs.

I still have GMRS/FRS and MURS but these are no longer my go-to modes for my local non-ham on-site simplex use. The DTRs and DLRs work so much better and are 100% digital.

I may order a few of these antennas to play with.


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[n1das]

This thread should be moved to the Motorola forum. It doesn't deserve to be next to the Cheap Chinese Radios (CCRs)! There is absolutely no comparison between Motorola DTRs and the CCRs.

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[Lowboy23]

I know there is no comparison between the DTRs and CCRs, but in the forum description it lists ISM 900 Mhz radios, so that's where I put it.

 

[radioman2001]

Looks just like the original antenna's the 800 STX and MT-9000 came with when new back in the 90's. Probably a ripoff of the M designed antenna, which was designed to get the RF above you head and especially your eyes.

 

[alcahuete]

Probably a ripoff of the M designed antenna

It IS a Motorola antenna.

I've had extraordinarily good luck with the 7 inchers. I'd be very curious to know if these would make a difference as well.

 

[IAmSixNine]

Had one of them in 800mhz many years ago for my MTS2000 and it was a slight improvement over the standard 800mhz antenna. On weak / further systems it was a big difference.

 

[N4KVE]

I've taken a few apart after the outside plastic got crispy, & the antenna fell apart. The actual wire antenna part is the same length as on the 4" stubby. Thin coax connects the base to the actual wire antenna. Its just mounted 6"-7" higher. The regular 7" whip works better, as the wire portion of the antenna is longer.

 

[n1das]

I've taken a few apart after the outside plastic got crispy, & the antenna fell apart. The actual wire antenna part is the same length as on the 4" stubby. Thin coax connects the base to the actual wire antenna. Its just mounted 6"-7" higher. The regular 7" whip works better, as the wire portion of the antenna is longer.

It's a coaxial aka sleeve dipole.

I would be interested in sweeping these with a network analyzer and have a look at the return loss for each design.


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[Lowboy23]

Yeah, that's how rubber duck dipoles are made-with a sleeve. And it is a Motorola antenna. Part number is 8505884r02.

 

[n1das]

Yeah, that's how rubber duck dipoles are made-with a sleeve. And it is a Motorola antenna. Part number is 8505884r02.

I just ordered a few of these to play with on my DTR650 radios.

I'm interested in sweeping this antenna and the 3.5" 1/4-wave and 7" 1/2-wave antenna on a network analyzer to see how they compare. A look at S11 to measure the return loss for each antenna would be interesting.

Wikipedia article on return loss:
https://en.wikipedia.org/wiki/Return_loss

 

[Lowboy23]

Cool. Let us know the results. I'm pretty sure the dipole will have the highest return loss. That Wiki article is kinda above my head, though.

 

[n1das]

This antenna appears to be NLA.

I have tried ordering it from 2 different distributors including the one posted and found my order cancelled both times. Somebody may have some in stock somewhere but I'm not going to search the end of the earth for it.

It's not a big deal and I will keep using the 7 inch half wave antenna on my DTRs.


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[RodStrong]

I've got a few dipoles laying around, most of them with plastic housings that have become brittle from age. I've found over the years that they are as good or better than standard. First used them in the late 80's on MTX800's. The negatives are they are much more rigid and longer, so they are less comfortable to carry and are generally more unpopular with users. That said, I have an old beat up dipole repaired with shrink tubing on the assigned radio that I carry, and I can have any antenna I want. Just my two cents.

 

[Lowboy23]

Rubber duck dipoles for this band are plentiful, as long as you are not using a handheld radio. The vast majority on the market seem designed for other purposes like wi-fi routers, having lossy swivel bases and wrong connectors. But, for anyone wanting to pursue it further, check this little fella out-https://www.arcantenna.com/8-inch-tuf-duck-1-2-wave-dipole-two-way-radio-antenna-900-mhz-ism.html. This Laird looks a perfect fit just like the Motorola.

 

[n1das]

Rubber duck dipoles for this band are plentiful, as long as you are not using a handheld radio. The vast majority on the market seem designed for other purposes like wi-fi routers, having lossy swivel bases and wrong connectors. But, for anyone wanting to pursue it further, check this little fella out-https://www.arcantenna.com/8-inch-tuf-duck-1-2-wave-dipole-two-way-radio-antenna-900-mhz-ism.html. This Laird looks a perfect fit just like the Motorola.

The connector on the Laird antenna is the wrong gender for a DTR radio. The DTRs have a recessed male SMA connector like most Part 90 radios have. The Laird antenna can be put on with an adapter but I would rather not use an adapter between the antenna and the radio.

Antennas that we can use on the older DTRs could also be used on the new DTR600 and DTR700 models. The DTR600 and DTR700 models received FCC certification yesterday (11/8/2018) and are due out in December.



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[Lowboy23]

The wrong connector? OK. Sure don"t want to use an adapter. Kinda defeats the whole purpose of using a slightly better antenna.

 

[n1das]

The wrong connector? OK. Sure don"t want to use an adapter. Kinda defeats the whole purpose of using a slightly better antenna.

I would rather find a better antenna with the right connector on it. Does Laird make a 900MHz dipole with the right connector on it for the DTRs?

I generally don't like using adapters on a handheld radio because the connection is more fragile and easily broken as the radio gets bumped and banged around. It becomes more trouble than it's worth. Years ago I've seen many hams build a "tree" of BNC adapters so they can fold the antenna on their 2m HT down beside the radio when not in use. It caused nothing but trouble as the antenna connection through the adapters frequently went intermittent. The benefits of using a better antenna were nullified by intermittent connections.

The 7 inch half wave antenna on the DTRs does very well as it is. The new DTR700 and DTR600 models will come with a half wave antenna.





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