Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: Cross Band Repeater Question  (Read 4623 times)
N5INP
Member

Posts: 709




Ignore
« on: July 29, 2013, 11:20:33 AM »

It may be that the name actually answers my question (cross band) but I can't specifically find the answer in the manuals I've been looking at. I do see the examples go cross band, i.e. from VHF to UHF and vice versa. But can these radios do same band repeating? RX on VHF and retransmit on another VHF freq, or the same for UHF?
Logged

WB2WIK
Member

Posts: 20536




Ignore
« Reply #1 on: July 29, 2013, 11:24:03 AM »

No, they cannot.
Logged
KA4POL
Member

Posts: 1851




Ignore
« Reply #2 on: July 29, 2013, 11:32:50 AM »

It may be that the name actually answers my question (cross band) ,,,
It does indeed. Cross Band is not same band.
Logged
K6LCS
Member

Posts: 1492


WWW

Ignore
« Reply #3 on: July 29, 2013, 11:33:40 AM »

What's your application? You are describing what a traditional repeater does ...
Logged

Clint Bradford, K6LCS
http://www.k6lcs.com
N3HFS
Member

Posts: 191




Ignore
« Reply #4 on: July 29, 2013, 11:35:30 AM »

But can these radios do same band repeating? RX on VHF and retransmit on another VHF freq, or the same for UHF?
That's a lot harder to do because there has to be filtering between the transmitter and the receiver of closely spaced radios.  Without adequate filtering (bandpass/band reject), the receiver will be saturated with the signal from the transmitter and therefore be unable to function well, if at all.

Physics seems to dictate that the closer the spacing (and the longer the wavelengths involved), the larger the physical size of the filters.  Repeater "cans" (they look like painted steel cylinders with screw-in knobs on the top) can be a couple of feet tall and eight inches wide in the case of 2-meter repeaters, and even larger in height and width on 6-meter and 10-meter repeaters.  The reason? The spacing between receive and transmit frequencies shrinks as you go to lower frequencies since there's generally less space there - there's other reasons, too, such as tradition/legacy and the longer wavelengths. 

Trying to separate 146.76MHz from 146.16MHz (a typical 2-meter repeater pair) is a LOT harder than separating 146.58MHz from 446.050MHz.  The front-end need only a very wide filter to keep 440MHz and 144MHz signals well isolated from each of its receivers - this can be accomplished very effectively using far smaller and cheaper components.

You will find hams trying to create effective (in-band) repeaters without the expensive isolation cans I mentioned above.  Some approaches include spacing RX and TX antennas directly beneath each other, or vastly far apart (horizontally) from each other, in various schemes to keep one side from affecting the other's performance. 

The end result is that you pay for narrower spacing between input and output frequencies, either in component costs and complexity or in performance.
Logged
N5INP
Member

Posts: 709




Ignore
« Reply #5 on: July 29, 2013, 12:13:16 PM »

Thanks for the explanations.

What's your application? You are describing what a traditional repeater does ...

No application - just wondering what the capabilities of these radios are.  Smiley

Logged

K1CJS
Member

Posts: 5807




Ignore
« Reply #6 on: July 29, 2013, 04:30:22 PM »

No, it just won't work.  The minute the transmitter kicked on the receiver would desensitize and lose the incoming signal--then the radio transmitter would 'lock' on.
Logged
VE5EIS
Member

Posts: 52


WWW

Ignore
« Reply #7 on: July 29, 2013, 08:43:22 PM »

In some jurisdictions (like Canada) you need a top-class ham certificate/license to use same-band repeating too - precisely because it requires some knowledge of duplexers etc.
Logged
WN2C
Member

Posts: 428




Ignore
« Reply #8 on: July 30, 2013, 09:02:25 AM »

Thanks for the explanations.

What's your application? You are describing what a traditional repeater does ...

No application - just wondering what the capabilities of these radios are.   Smiley



What radio?
Logged
N5INP
Member

Posts: 709




Ignore
« Reply #9 on: July 30, 2013, 10:02:03 AM »

What radio?

Generally any radio that can cross band repeat. But they've already told me it won't work that way.
Logged

N3HFS
Member

Posts: 191




Ignore
« Reply #10 on: July 30, 2013, 10:03:51 AM »

What radio?

There is a recent thread in this (VHF/UHF) forum about the new Powerwerx DB750X which mentioned its documented ability to do crossband repeat (144/440 MHz).  This is probably where the OP's question was stirred into being.

http://www.eham.net/ehamforum/smf/index.php/topic,90926.0.html

Edit: N5INP, I see you answered at the same time I did.  Your answer is obviously definitive!
Logged
N2OBS
Member

Posts: 5


WWW

Ignore
« Reply #11 on: July 31, 2013, 10:45:58 PM »

There are simplex crossband frequencies too.  One for mobile and handheld.  A pamphlet came out years ago and if need be i'll dig it out again just for fun.

73 de N2OBS
Keith from Summerville, SC
Logged
KD8DVR
Member

Posts: 27




Ignore
« Reply #12 on: August 16, 2013, 05:50:00 PM »

The new Puxing PX-UV973 HT will do cross-band repeat.  Also full duplex.. also true dual receive.  First of the Chinese HTs to do this. 

Here is some discussion:

http://groups.yahoo.com/group/uv973/
Logged

All items presented here are personal opinion only and may or may not deviate from actual fact.
N5INP
Member

Posts: 709




Ignore
« Reply #13 on: August 16, 2013, 07:17:40 PM »

The new Puxing PX-UV973 HT will do cross-band repeat.  Also full duplex.. also true dual receive.  First of the Chinese HTs to do this. 

Here is some discussion:

http://groups.yahoo.com/group/uv973/

Wow. $85. Do I need yet another Chinese HT?  Cheesy
Logged

KD8DVR
Member

Posts: 27




Ignore
« Reply #14 on: August 18, 2013, 10:14:36 AM »

The new Puxing PX-UV973 HT will do cross-band repeat.  Also full duplex.. also true dual receive.  First of the Chinese HTs to do this. 

Here is some discussion:

http://groups.yahoo.com/group/uv973/

Wow. $85. Do I need yet another Chinese HT?  Cheesy

Yes.. Yes you do Smiley
Logged

All items presented here are personal opinion only and may or may not deviate from actual fact.
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!