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Author Topic: 1.2 GHz FM  (Read 1648 times)
KC1MK
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Posts: 24




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« on: August 28, 2004, 10:50:12 PM »

Does anyone have any suggestions/tips for someone getting into 1.2 GHz FM. There are a few 1.2-GHz repeaters in the area, but the closest is probably about 10-15 miles away.

Thanks and 73,
Jeff, KC1MK
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WF6J
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Posts: 32




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« Reply #1 on: August 29, 2004, 12:28:20 AM »

Therer are several rigs that run at 1.2GHz.  We have two local repeaters and a network in Northern CA that works well.

I have Kenwood's TS-2000X, TM-741A mobile, ther is also the TM541A (rare used).  Most of the manufactuers have 1.2 plus you can buy 1.2GHz transverters from several sources. There are also handhelds. Depends on what your op preferences are.
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KZ1X
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Posts: 3229




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« Reply #2 on: August 29, 2004, 09:26:00 AM »

I have questions about 1.2 GHz FM.

Why do you want to use this band?  I know a LOT of good reasons I'd like to do so, but, what are yours?

For example, you may wish to consider how feedline loss affects a radio's performance on this band.  It really is significant.  So, if you want a good reason to learn about transmission lines, this is a good band to get active on!

Or, you may wish to truly understand the concept of multipath.  This band dishes it up, in abundance.

So, tell us more about why YOU are interested in this band.  
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KC1MK
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Posts: 24




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« Reply #3 on: August 29, 2004, 12:16:49 PM »

I am interested in this band for several reasons. Some of these include (not necessarily in order):
- Antenna experimentation
- Feedline behaviour and performance in this part of the spectrum
- Propagation
- Talking to other amateurs with similar interests
- Learning something new

73,
Jeff, KC1MK
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KZ1X
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Posts: 3229




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« Reply #4 on: August 29, 2004, 01:35:42 PM »

Well, Jeff, you seem to be a shoo-in to really enjoy this band, and you will learn a LOT from it.

The price of entry can be high, though, if one buys simply off-the-shelf gear.

Since the Japanese largely withdrew from the US 1.2 GHz market (they still sell lots of their 1.2 gear in Japan only) you will have to make due with used equipment, or, import your own ... or use a transverter, as was mentioned before.

Test gear is also sometimes challenging.  None of the common MFJ-type 'ham' stuff works up there.

Let us all know wht you end up with and what you think of it all.
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K7VO
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Posts: 1010




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« Reply #5 on: August 29, 2004, 02:02:06 PM »

Hi, Jeff,

I'm a former 1.2GHz repeater owner (I moved and sold the repeater) and I've been active on FM/SSB/CW on the band on and off over the years.  I am planning on putting up the first repeater in my area in the not too distant future.

10-15 miles should be no problem with a good mobile unit and a decent mobile antenna if the repeater antennas are up at a reasonable height (say over 100'-150').  There are excellent rigs for 1.2GHz both on the new and used market.

One particularly good source for reasonable used gear is Rodney Tom, KH7L, who is now in Japan.  23cm is the single most popular repeater band over there and he often finds good deals on used gear and sells them to U.S. hams.  His passions are QRP (especially Mizuho gear), VHF/UHF weak signal (also QRP), and 23cm, so that's what he gets.  You can either buy direct from him or through one of his eBay auctions (user ID: hiauctions).  Usually direct is a better deal, but not always.  See: http://www.qsl.net/kh7l/rigs.html  Rod is very fast to ship, 100% honest, and an all around great guy to deal with.  I've bought from him on a number of occasions and have always been fully satisfied.  You'll get your equipment typically within a week of him receiving payment (PayPal or international money order) via Global EMS.  Don't be afraid of importing through him.  He's got a fantastic track record and a well earned reputation.

Good choices for recent vintage used gear are the Icom IC-1210 or IC-1200 and the Yaesu FT-2312R.  The Kenwood TM-541 is overpriced, IMHO, and is prone to display failure.  There are also good multiband mobile rigs that can include 23cm as an option.  I believe the Kenwood TM-741A is on closeout now, but my feelings about it are the same as about the TM-541A.  Other choices (used only) would include the Icom Delta-100, IC-901A, and IC-900.

You can, of course, also go with multimode base gear.  If you are at all interested in doing satellite work or VHF/UHF contesting in the future this is unquestionably the way to go and you'd still have your FM capability.  This is, of course, expensive.  The TS-2000 is one possibility.  The Icom IC-910H is another, perhaps better, choice.  A used Yaesu FT-736R, Icom IC-1271A, IC-970H, or Kenwood TS-790A are things you can find on the used market that would do a great job for you.

The key to everything, of course, is the antenna.  Comet, Diamond, Maldol, and Larsen all make good mobile antennas for the band, either single band or in combination with 2m/70cm, just 70cm, or 13cm.  Base antennas can be loop yagis (Down East Microwave), coventional yagis (M2), quads (Shimizu), or part of a log periodic covering many VHF/UHF bands (Create, KMA, Cushcraft), as well as omnidirectional verticals (Comet, Diamond, Maldol) in either single band or multiband configurations.  Shimizu makes a very small 7 element quad, the SA-231, which is ideal for rover work as well, and I believe Diamond and Comet have similar  small yagis.

Whether you are doing a base or mobile installation you need to remember that feedline losses can be pretty awful at microwave frequencies. Even losses from connectors matter.  Go with good quality N connectors whether mobile or base.  Comet and Diamond both sell extra low loss small coax for this application in short lengths with connectors on for mobile installations.  For a base installation you probably want hardline, though in a pinch you can get away with Times LMR-600, LMR-400, or even Belden 9913 if the run is short.  Keep the run as short as possible to the tower, use the absolutely best feedline you can afford, and don't ever patch together two pieces using a barrel connector.

In other words, you have a ton of options out there.  Do some homework and choose the best for you. I've already decided on a Shimizu SA-231 quad.  Which radio or transverter I'll end up with this time still isn't clear.

72/73,
Caity
K7VO
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K7VO
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Posts: 1010




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« Reply #6 on: August 29, 2004, 02:04:23 PM »

Hi again, Jeff.

I almost forgot to mention digital voice.  Icom's ID-1 mobile rig can do conventional analog FM or digital at a cost similar to a Kenwood TM-541.  This may well be worth considering.

Oh, and no, the Japanese have not pulled out of 1.2GHz in the USA.  Only Yaesu has done that.  Icom and Kenwood still sell new gear.  Alinco never got into 1.2GHz in the first place.

73,
Caity
K7VO
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KC1MK
Member

Posts: 24




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« Reply #7 on: August 30, 2004, 12:39:32 AM »

I would like to thank everyone for the very helpful advice, information, and encouragement. I have e-mailed Rod to see about possibly buying an Icom IC-1200 (for mobile and home use) and a Kenwood TH-59 handheld. I plan on getting into the weak-signal modes in the future, but will start with FM to get my feet wet.
Thanks and 73,
Jeff, KC1MK
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KC1MK
Member

Posts: 24




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« Reply #8 on: August 30, 2004, 10:46:50 PM »

I bought an Icom IC-1200 and a Kenwood TH-59 from Rod. As soon as they arrive and I use them a bit, I'll report back on my 1.2-GHz experience. I'm really looking forward to learning about 1.2-GHz operation!
73,
Jeff, KC1MK
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VR2XMQ
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Posts: 20


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« Reply #9 on: May 06, 2008, 10:32:38 PM »

I have a IC-120 with matching power booster ML-120 with the bottom end on the band starting at 1260.

Does anyone have any information on possible modifications for frequency expansion so that the bottom end can begin at 1240 MHz?

73 Steve, VR2XMQ

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