I am not familiar with the exact type of antenna you are talking about and I know that some will disagree but here goes any way:

IN GENERAL antenna length is very critical ONLY on TRANSMITTING.
Receive antennas are not as critical.

If you trim 3/4 inch from a TRANSMITTER antenna (at the frequency's we use) you are asking for trouble and will possibly destroy your transmitter.

If you trim 3/4 inch from a RECEIVER you will not harm the receiver ELECTRONICS. What you will do is shorten the effective range of your receiver. At the frequency's we use I don't think the shortened range will be much. I hesitate to list a distance because it will only start a debate in which there can be no winner. The best advice is, as always, do a very complete range check. I would do the check at a greater distance that normal just to be on the safe side.

Just one other note: Yes I know that when we operate our radios with the antenna down, such as for a range check, we are shortening the antenna. Why don't we harm our radios when we do this? The harm is caused over a period of time and depends on the amount of output power. Our relatively low power units can operate this way for quite a while. If you are in the habit of operating you radio for extended periods of time with the antenna down then the range check is just that much more important. This most likely the first place you will see a problem.

This might also explain some unexplained loss of control situations. This is a good thing to remember if the loss of control occurred at a greater distance AND no other explanation can be found.


Ronaldcorb

KA7RKO/26 years Electronics Tech.

PS: This is just my opinion and it is offered for entertainment purposes only.