Quantity Available
2
Posted
11 hours ago
Description
You are bidding on one RAAF Balun labelled Matching Unit, MU-1, with Ident. Y10A/501149. There are 2 .
It has 75 Ohm input and 200 Ohm output - see photos.
There is continuity between the 75 and 200 Ohm sides. So, I suspect it's a Ruthroff or Guanella design - multi-turn coaxial cable over a ferrite core – rather than an isolated transformer design.
I have not used or even opened it; so, I can't comment on frequency range or power-handling capacity.
The 75 Ohm side is unbalanced: a female, chassis-mounted N-type connector; the 200 Ohm side is balanced: two screw-down, open-wire terminals.
All original equipment manufactured components are present. The only shortcoming is that some of the mil green paint has peeled off and there is some rust on the mounting bracket.
You can
I had a specific antenna to feed. With a 75 Ohm input, I had to design and build a 50 to 75 Ohm Unbal-to-unbal because all my equipment is designed for 50 Ohm input / output. Instead, I designed and built my own Baluns for 50 Ohm coaxial input. So, these RAAF Baluns are unused, effectively new and available.
Packaging
I make no charge for packaging. Your item will be properly wrapped and packed to withstand the usual rigors of postal and courier delivery systems.
Payment
650, each
Shipping dimensions for one, cm
15 x 12 x 10
It has 75 Ohm input and 200 Ohm output - see photos.
There is continuity between the 75 and 200 Ohm sides. So, I suspect it's a Ruthroff or Guanella design - multi-turn coaxial cable over a ferrite core – rather than an isolated transformer design.
I have not used or even opened it; so, I can't comment on frequency range or power-handling capacity.
The 75 Ohm side is unbalanced: a female, chassis-mounted N-type connector; the 200 Ohm side is balanced: two screw-down, open-wire terminals.
All original equipment manufactured components are present. The only shortcoming is that some of the mil green paint has peeled off and there is some rust on the mounting bracket.
You can
- use it for feeding a 200 Ohm transmission line
- use it for directly feeding a 200 Ohm antenna
- use two of them back-to-back: feed your signal in via 75 Ohm coaxial cable, connect the 200 Ohm connectors via a 200 Ohm transmission line, and take your output from the second 75 Ohm N-type connector. Why? Over even modest distances, transmission lines have much lower losses than any coaxial cable.
- add it to your collection of RAAF radio equipment.
I had a specific antenna to feed. With a 75 Ohm input, I had to design and build a 50 to 75 Ohm Unbal-to-unbal because all my equipment is designed for 50 Ohm input / output. Instead, I designed and built my own Baluns for 50 Ohm coaxial input. So, these RAAF Baluns are unused, effectively new and available.
Packaging
I make no charge for packaging. Your item will be properly wrapped and packed to withstand the usual rigors of postal and courier delivery systems.
Payment
- If you are in Australia, I will accept payment by direct bank transfer, Money Order, or PayPal, but not posted cash. It is often cheaper to pay by bank transfer than by Money Order or PayPal.
- I will only accept cash if you collect the item from me.
- If you are outside Australia, I will only accept payment by bank transfer, Money Order or PayPal. All payments must be in AU$, unless we agree otherwise before your payment.
650, each
Shipping dimensions for one, cm
15 x 12 x 10
Condition of Item
As New
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