Re: AMSAT-BB Digest, Vol 2, Issue 504
Scott
The other downside is that even with two transceivers, I'm unable to work full-duplex. The two bands on the antenna use seperate elements and feed points, but share a boom. Transmitting on 2m completely overloads the front-end of the IC-7000. While full duplex would be useful, it's not absolutely necessary.
Theres also the old fashioned stub, you put a 2m quarter-wave open-circuit stub on the 70cm feeder close to the input of the preamp (maybe another close to the input of the rig). A little bit tricky to tune (fabricate it long and snip tiny bits of it off until you get maximum attenuation).
73 Richard G3RWL
Hi Richard, A quarter wave stub tuned to 2 meters will be 3/4 wave at 70 cm. Therefor it will reject 70 cm as well. Greetings from Copenhagen. 73 OZ1MY Ib ----- Original Message ----- From: richard@g3rwl.demon.co.uk To: amsat-bb@amsat.org Sent: Tuesday, August 14, 2007 10:32 AM Subject: [amsat-bb] Re: AMSAT-BB Digest, Vol 2, Issue 504
Scott
The other downside is that even with two transceivers, I'm unable to
work
full-duplex. The two bands on the antenna use seperate elements and feed points, but share a boom. Transmitting on 2m completely overloads the front-end of the IC-7000. While full duplex would be useful, it's not absolutely necessary.
Theres also the old fashioned stub, you put a 2m quarter-wave open-circuit
stub on the 70cm feeder close to the input of the preamp (maybe another close to the input of the rig). A little bit tricky to tune (fabricate it long and snip tiny bits of it off until you get maximum attenuation).
73 Richard G3RWL
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
And my solution has been to use a "splitter" (also known as duplexers or diplexers) designed to work with a dual band antenna. The common goes to the antenna, the UHF connection to the UHF rig and the VHF to a small dummy load... it always seem to work here... Most are listed under the Diamond brand name.
good luck
Graham G3VZV
----- Original Message ----- From: richard@g3rwl.demon.co.uk To: amsat-bb@amsat.org Sent: Tuesday, August 14, 2007 9:32 AM Subject: [amsat-bb] Re: AMSAT-BB Digest, Vol 2, Issue 504
Scott
The other downside is that even with two transceivers, I'm unable to work full-duplex. The two bands on the antenna use seperate elements and feed points, but share a boom. Transmitting on 2m completely overloads the front-end of the IC-7000. While full duplex would be useful, it's not absolutely necessary.
Theres also the old fashioned stub, you put a 2m quarter-wave open-circuit stub on the 70cm feeder close to the input of the preamp (maybe another close to the input of the rig). A little bit tricky to tune (fabricate it long and snip tiny bits of it off until you get maximum attenuation).
73 Richard G3RWL
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (3)
-
Graham Shirville -
OZ1MY -
richard＠g3rwl.demon.co.uk