HT750/1250 RF Terminator?
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HT750/1250 RF Terminator?
I'm looking to do some testing with my HT750 and HT1250 (46mhz range). Im looking to see if there is an RF terminator that I can buy and/or build for the HT series. Im sorta stuck and looking for some direction. Thanks!
Re: HT750/1250 RF Terminator?
First thing you will require, is the adaptor that fits the radio.
Second, it's the same adaptor that is used on the GP300/P110 radios of old.
It is a threaded phono jack which transitions to a BNC-F connector.
Don't bother with Circle-M, they want far more than it is worth.
You should be able to hamfest this item for less than a $10.00 bill in the package.
As for the termination, get a quality 50 ohm load, NOT one of those cheaply assembled resistors in an aluminum tube that junk shack sells, or used to sell(they are a simple carbon resistor, and the 'heatsink' is only for show as it does not make physical contact with the termination).
Decibel makes a fine 30 watt load, or you can try Tessco, or Tulley's...actually, any good shop should carry quality terminations.
You can also find them on surplus Isolators/circulators as well.
I have several ranging from a simple 5 watt load, to a 'monster' 1,000 watt 'block' for high power testing.
Most are type 'N' female, with several others being of the type 'N' male.
A short run of cable(high quality), and a stable load is all you need.
Transisitions are easy to acquire from parts houses like Fry's electronics, ham radio stores like HRO, AES and R&L and so on...
Do NOT buy screw-on connectors as they are garbage and do NOT provide a measurable or repeatable 50 Ohm rating when swept with a bridge and monitor.
You can also contemplate the purchase of a power attenuator if you plan on keeping a transmit condition of a continuous nature.
This way, you can 'create' your own output levels using a combination of attenuators instead of a load.
Of course, these would appear like a load, but with a male and female connector on each end.
Second, it's the same adaptor that is used on the GP300/P110 radios of old.
It is a threaded phono jack which transitions to a BNC-F connector.
Don't bother with Circle-M, they want far more than it is worth.
You should be able to hamfest this item for less than a $10.00 bill in the package.
As for the termination, get a quality 50 ohm load, NOT one of those cheaply assembled resistors in an aluminum tube that junk shack sells, or used to sell(they are a simple carbon resistor, and the 'heatsink' is only for show as it does not make physical contact with the termination).
Decibel makes a fine 30 watt load, or you can try Tessco, or Tulley's...actually, any good shop should carry quality terminations.
You can also find them on surplus Isolators/circulators as well.
I have several ranging from a simple 5 watt load, to a 'monster' 1,000 watt 'block' for high power testing.
Most are type 'N' female, with several others being of the type 'N' male.
A short run of cable(high quality), and a stable load is all you need.
Transisitions are easy to acquire from parts houses like Fry's electronics, ham radio stores like HRO, AES and R&L and so on...
Do NOT buy screw-on connectors as they are garbage and do NOT provide a measurable or repeatable 50 Ohm rating when swept with a bridge and monitor.
You can also contemplate the purchase of a power attenuator if you plan on keeping a transmit condition of a continuous nature.
This way, you can 'create' your own output levels using a combination of attenuators instead of a load.
Of course, these would appear like a load, but with a male and female connector on each end.
Re: HT750/1250 RF Terminator?
Can someone show me the proper connector to use?
Thanks!
Thanks!
Re: HT750/1250 RF Terminator?
Hi Two Tone,
I think you can see what the adapter looks like in the epay ad:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0155118210
W8RW
I think you can see what the adapter looks like in the epay ad:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0155118210
W8RW
-
Tom in D.C.
- Posts: 3859
- Joined: Tue Sep 04, 2001 4:00 pm
- What radios do you own?: Progreso soup can with CRT
Re: HT750/1250 RF Terminator?
The point to be made is that the GP300's antenna connector provides you with the
positive/hot connection only but no ground. If you use the suggested adapter then
your dummy load will have a ground reference, which means it will have a complete
circuit and thus will give you accurate and steady readings.
positive/hot connection only but no ground. If you use the suggested adapter then
your dummy load will have a ground reference, which means it will have a complete
circuit and thus will give you accurate and steady readings.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
Re: HT750/1250 RF Terminator?
At 46 mHz you could build a "dummy" load resistor from four 200 ohm 2 watt carbon resistors in parallel.
Keep the resistor leads as short as possible. I built one on a BNC chassis connector.
Keep the resistor leads as short as possible. I built one on a BNC chassis connector.